73120 Learning OutcomesAfter reading this chapter, .docx

731
20
Learning Outcomes
After reading this chapter, you will be able to:
20.1 Distinguish between foodborne infection and
foodborne intoxication and provide an example
of each.
20.2 Summarize strategies to prevent foodborne
illness in the home and when traveling.
20.3 Describe how the food supply is protected in
the United States.
20.4 Compare the risks and benefits of food
additives and the use of hormones, antibiot-
ics, and pesticides in both traditionally and
organically grown food.
20.5 Explain what constitutes a sustainable food
system.
20.6 Compare the benefits and risks of the use of
biotechnology in our current food system.
True or False?
1. Foods that contain pathogens that
cause foodborne illness always smell bad. T/F
2. Handwashing is more effective in

preventing food contamination than using a hand sanitizer. T/F
3. A kitchen sponge is a prime environment for the breeding and
spread of bacteria. T/F
4. Freezing foods kills the harmful bacteria. T/F
5. Leftovers that have been stored in the fridge for a week are
safe to eat. T/F
6. As long as the expiration date hasn’t passed, packaged food
is always safe to eat. T/F
7. Food additives must demonstrate a “zero risk” of cancer to
human beings in order to meet FDA approval. T/F
8. A diet consisting only of locally grown foods is a sustainable
diet. T/F
9. Foods grown organically that carry the USDA organic seal
are free of pesticides. T/F
10. Genetically engineered foods are
plentiful in the United States. T/F
See page 773–774 for the answers.
Food Safety,
Technology, and
Sustainability
732 Chapter 20 | Food Safety, Technology, and
Sustainability
What Causes Foodborne Illness?
LO 20.1 Distinguish between foodborne infection and
foodborne intoxication

and provide an example of each.
Foodborne illness is any disorder caused by consuming
contaminated food. It is a major
preventable public health threat worldwide. Every year in the
United States, 1 in 6 Ameri-
cans (or 48 million people) experience foodborne illness, and
about 128,000 are hospital-
ized.1 Foodborne illness most commonly results in
gastrointestinal symptoms such as
cramps, diarrhea, and nausea and vomiting, but in extreme
circumstances it can result in
death. Approximately 3,000 Americans die of foodborne illness
every year.2
Pathogens and Their Toxins Cause Most Foodborne Illness
The two types of foodborne illness are infection and
intoxication. Consuming foods or
beverages that are contaminated with disease-causing
organisms, known as pathogens,
causes foodborne infection. Once ingested, the pathogens
multiply in the GI tract and
cause illness. Pathogens commonly implicated in foodborne
infection include viruses,
bacteria, molds, parasites, and prions (Table 20.1).
Eating foods contaminated with a toxin causes foodborne
intoxication. Viruses
and parasites do not cause foodborne intoxication. Certain
species of bacteria, however,
do secrete toxins. These include Clostridium botulinum,
Staphylococcus aureus, Bacillus cereus,
and Escherichia coli. Bacterial foodborne intoxication generally
is caused by enterotoxins
(entero = intestine, toxin = toxic), which quickly produce
gastrointestinal symptoms such

as nausea and vomiting—in some cases within 30 minutes of
consuming the contami-
nated food.3 Some bacteria, such as C. botulinum, secrete
neurotoxins (neuro = nerve) that
harm the nervous system. Toxins can also accumulate naturally
in plants or seafood or
result from chemical contamination. These types are discussed
later in this chapter.
Pathogens may be present in the raw ingredients of the food or
may contaminate the food
at any stage of the food system. For example, fruit flies have
been shown to transfer toxin-
producing Escherichia coli O157:H7 to apples under laboratory
conditions.4 E. coli as well as
several other pathogens are found in the GI tract and fecal
matter of humans or animals.
Food may become contaminated with these pathogens if it
comes into contact with fecal
matter, and individuals can become infected by putting food or
hands that have been in
contact with fecal matter into their mouths. This is a common
route of transmission of
foodborne illness and is called the fecal-to-oral transmission
route.
foodborne illness Sickness caused by
consuming pathogen- or toxin-containing
food or beverages. Also known as foodborne
disease or food poisoning.
pathogens Collective term for disease-
causing organisms. Pathogens include
microorganisms (viruses, bacteria) and
parasites and are the most common source of
foodborne illness.

toxin Poison that can be produced by living
organisms.
fecal-to-oral transmission Spread of
pathogens by putting something in the mouth,
such as hands or food, that has been in
contact with infected stool.
Have you ever thought about where food comes from before it
appears on the supermarket shelf or how safe that food is for
you? No matter what you are eating, it likely started out on a
farm. Getting
food safely from farms to your plate requires several steps and a
huge investment of human and natural
resources.
Thanks to monitoring and regulation by the U.S. Food and Drug
Administration (FDA), the U.S.
Department of Agriculture (USDA), and other government
agencies, consumers in the United States
enjoy a relatively safe food supply. As we explain this chapter,
however, foodborne illness continues to
be a threat. Moreover, as the world’s population continues to
increase, the pressure to produce more
food with limited natural resources has led to technological
changes in the food system that have had
environmental costs, including depletion of natural resources
and pollution of air, soil, and water. In
this chapter we discuss the causes of foodborne illnesses and

strategies to prevent them. We also explore
techniques of modern food production and their effects on our
health and our environment.
food system All processes and infrastructure
involved in feeding a population: growing,
harvesting, processing, packaging,
transporting, marketing, and consuming food.
What Causes Foodborne Illness? 733
Microbe Where You Find It How You Can Get It What You May
Experience
Viruses
Norovirus In the stool or vomit of infected
individuals
Fecal-to-oral transmission; eating
ready-to-eat foods or drinking liquids
contaminated by an infected person;
eating contaminated shellfish; touch-
ing contaminated objects and then
putting hands in mouth
Watery diarrhea, nausea and vomit-
ing, flulike symptoms; possible fever.
Symptoms can appear 24–48 hours
after onset, last 24–60 hours, and are
typically not serious.
Hepatitis A (HAV) In the stool of infected

individuals
Fecal-to-oral transmission; eating raw
produce irrigated with contaminated
water; eating raw or undercooked
foods that have not been properly
reheated; drinking contaminated
water
Diarrhea, dark urine, jaundice, flulike
symptoms that can appear 30 days
after incubation and can last 2 weeks
to 3 months.
Bacteria
Campylobacter jejuni GI tracts of animals and birds,
unpasteurized milk, untreated
water, and sewage
Drinking contaminated water or raw
milk; eating raw or undercooked
meat, poultry, or shellfish
Fever, headache, and muscle pain
followed by diarrhea (sometimes
bloody), abdominal pain, and nausea;
appears 2–5 days after eating; may
last 7–10 days; Guillain-Barré syn-
drome may occur.
Clostridium botulinum Widely distributed in nature in
soil, water, on plants, and in
the GI tracts of animals and
fish; grows only in environ-
ments with little or no oxygen

Eating improperly canned foods,
garlic in oil, vacuum-packaged and
tightly wrapped food
Bacteria produce a toxin that causes
illness by affecting the nervous sys-
tem. Symptoms usually appear after
18–36 hours. May experience double
vision, droopy eyelids, trouble speak-
ing and swallowing, and difficulty
breathing. Fatal in 3–10 days if not
treated.
Clostridium
perfringens
Soil, dust, sewage, and GI
tracts of animals and humans;
grows only in little or no
oxygen
Called “the cafeteria germ” because
many outbreaks result from eating
food left for long periods in steam
tables or at room temperature; bac-
teria are destroyed by cooking, but
some spores may survive
Bacteria produce toxin that causes
illness. Diarrhea and gas pains may
appear 8–24 hours after eating; usu-
ally last about 1 day, but less severe
symptoms may persist for 1–2 weeks.
Escherichia coli

O157:H7
GI tracts of some mammals,
unpasteurized milk, unchlo-
rinated water; one of several
strains of E. coli that can
cause human illness
Drinking contaminated water, unpas-
teurized apple juice or cider, or
unpasteurized milk; eating raw or rare
ground beef or uncooked fruits and
vegetables
Diarrhea or bloody diarrhea, abdomi-
nal cramps, nausea, and weakness.
Can begin 2 to 5 days after food is
eaten, lasting about 8 days.
Small children and older adults may
develop hemolytic uremic syndrome
(HUS), which causes acute kidney
failure. A similar illness, thrombotic
thrombocytopenic purpura (TTP),
may occur in adults.
Enterotoxigenic Esch-
erichia coli (major
cause of traveler’s
diarrhea)
GI tracts of some mammals
and unpasteurized dairy prod-
ucts; more common in devel-
oping countries

Fecal-to-oral transmission; consum-
ing stool-contaminated water and
foods from unsanitary water supplies
and food establishments
Diarrhea, nausea and vomiting, stom-
ach cramping, bloating, fever, and
weakness
Listeria
monocytogenes
GI tracts of humans and
animals, milk, soil, leafy veg-
etables; can grow slowly at
refrigerator temperatures
Eating ready-to-eat foods such as
hot dogs, luncheon meats, cold cuts,
fermented or dry sausage, other
deli-style meat and poultry, or soft
cheeses; drinking unpasteurized milk
Fever, chills, headache, backache,
sometimes upset stomach, abdomi-
nal pain, and diarrhea; may take up
to 3 weeks to become ill; may later
develop more serious illness in high-
risk individuals
TABLE 20.1 Pathogens That Commonly Cause Foodborne
Illness
(continued)

Sustainability
virus Microscopic organism that carries
genetic information for its own replication; can
infect a host and cause illness.
host Living plant or animal (including a human)
that a microbe infects for the sake of reproducing.
Microbe Where You Find It How You Can Get It What You May
Experience
Salmonella (over
2,300 types)
GI tracts and feces of animals;
Salmonella enteritidis in eggs
Eating raw or undercooked eggs,
poultry, and meat, unpasteurized milk
and dairy products, and seafood;
can also be spread by infected food
handlers
Stomach pain, diarrhea, nausea,
chills, fever, and headache usually
appear 8–72 hours after eating. May
last 1–2 days.
Shigella (over 30
types)
Human GI tract; rarely found in
other animals

Fecal-to-oral transmission by con-
suming contaminated food and water.
Most outbreaks result from eating
food, especially salads, prepared and
handled by workers with poor per-
sonal hygiene
Disease referred to as “shigellosis” or
bacillary dysentery. Diarrhea contain-
ing blood and mucus, fever, abdomi-
nal cramps, chills, and vomiting begin
12–50 hours from ingestion of bacte-
ria; can last a few days to 2 weeks.
Staphylococcus
aureus
On humans (skin, infected
cuts, pimples, noses, and
throats)
Consuming foods that were contami-
nated by being improperly handled;
bacteria multiply rapidly at room
temperature
Bacteria produce a toxin that causes
illness. Severe nausea, abdominal
cramps, vomiting, and diarrhea occur
1–6 hours after eating; recovery
within 2–3 days.
Parasites
Cryptosporidium

parvum
In the intestines of humans
and animals
Fecal-to-oral transmission; drinking
contaminated water; eating contami-
nated produce
Stomach pains, diarrhea, cramps,
fever, and vomiting
Cyclospora
cayetanensis
Human stool Fecal-to-oral transmission; drinking
nated produce
Diarrhea, flatulence, stomach
cramps, vomiting, fatigue
Giardia lamblia In the intestines of humans
and animals
Fecal-to-oral transmission; drinking
nated produce
Diarrhea, stomach pains, flatulence
Trichinella spiralis In undercooked or raw meats
containing Trichinella worms
Raw or undercooked contaminated
meat, usually pork or game meats

Nausea and vomiting, diarrhea, fever,
aching joints and muscles
Sources: Data from Centers for Disease Control and Prevention
(CDC). 2004. Diagnosis and Management of Foodborne Illness:
A Primer for Physicians; CDC. 2012. Norovirus;
CDC. 2014. Hepatitis A Information for the Public; CDC. 2006.
Traveler’s Diarrhea; Diagnosis and Management of Foodborne
Illnesses: A Primer for Physicians. MMWR Recom-
mendations and Reports 50 (January 2001):1–69; CDC. 2014.
Parasites: Food. All available at www.cdc.gov. USDA Food
Safety and Inspection Service. 2013. Foodborne Illness:
What Consumers Need to Know. Available at
https://www.fsis.usda.gov/wps/portal/fsis/topics/food-safety-
education/get-answers/food-safety-fact-sheets/foodborne-
illness-and-
disease/foodborne-illness-what-consumers-need-to-
know/CT_Index. Accessed April 2017; USDA Food Safety and
Inspection Service. 2015. Parasites and Foodborne Illness.
Available at https://www.cdc.gov/parasites/food.html. Accessed
April 2017.
TABLE 20.1 Pathogens That Commonly Cause Foodborne
Illness (continued)
Eating contaminated food does not always result in foodborne
illness. Many patho-
gens are killed in the mouth by antimicrobial enzymes and in
the stomach by hydrochloric
acid. In addition, the potential for a pathogen to cause illness
depends on the amount
that is consumed, the potency, and the nutritional and immune
status of the person who
consumes it. Pathogens that survive the natural defense systems
of the body undergo an

incubation period before the symptoms of illness begin. The
delay in the time between when
the pathogen is consumed and when it causes illness depends on
the type and number of
pathogens swallowed and can range from a few hours to a few
weeks (refer to Table 20.1).
In the United States the majority of foodborne illness is caused
by infection or
intoxication from five pathogens: norovirus, Salmonella
(bacterium), Clostridium perfringens
(bacterium), Campylobacter (bacterium), and Staphylococcus
aureus (bacterium that produces a
toxin).5 Together these pathogens are estimated to account for
91 percent of all domesti-
cally acquired cases of foodborne illness in the United States.
The differences between
the major pathogen groups are discussed next.
Viruses
The term virus denotes a microscopic infectious agent that
contains genetic information
(DNA or RNA) but must enter a living host, such as a plant or
animal cell, to engage in
metabolism and reproduction and thus survive. When an
individual eats a food that is
contaminated with a virus, the pathogen can invade the cells of
the stomach and intestinal
walls. The virus can then cause the cells’ genetic material to
start producing more viruses,
ultimately leading to illness.6 One virus species—norovirus—is

currently responsible
for more than half of all foodborne illness in the United States,
making it the single most
common cause of foodborne disease in this country.7
Bacteria
Bacteria are single-celled organisms that lack a nucleus.
Thousands of types of bacteria
are naturally present in our environment. If you were to swab
your kitchen sink right now
and look at the results under a microscope, you would find that
there are about 16 million
bacteria living on each square centimeter (less than half an
inch) of the sink. Whereas
viruses need a host to survive, bacteria can flourish on both
living and nonliving surfaces
and can multiply on sponges, dishtowels, cutting boards and
countertops, and in sinks.
Given the right conditions, a single bacterium can produce
colonies of billions of bacteria
over the course of just one day.
Not all bacteria cause disease in humans. Recall from Chapter 3
that the GI tract
harbors in excess of 1,000 different types of bacteria, many of
which are beneficial to
health.8 Some produce small amounts of vitamins or enhance GI
functioning, whereas
others may aid in weight regulation or maintenance of the lining
of the GI tract.9 Harm-
ful bacteria that enter the GI tract compete for resources with
the resident GI flora and,
depending on the amount and species of invading bacteria and
the condition of the human
host, may cause illness.

Contamination of food by certain types of bacteria causes it to
spoil; that is, the
quality of the food deteriorates. The same bacterial species may
or may not introduce
pathogens that cause foodborne illness. Though most
individuals do not become seriously
ill after eating spoiled foods, these items can cause nausea and
shouldn’t be eaten. In con-
trast to spoiled foods, contaminated foods that contain bacterial
pathogens may look and
smell perfectly fine. It is not safe to eat food just because it
“looks fine” or “smells OK.”
Bacteria may contaminate raw meat, poultry, seafood, eggs, and
produce. Lettuce,
tomatoes, sprouts, and melons—which are eaten raw—
frequently carry pathogenic bac-
teria. Although they can grow in just about any food, bacteria
grow particularly well on
foods high in protein, such as meat, dairy foods, and cooked
beans. Even ready-to-eat
foods that have been cooked may become contaminated with
bacteria from raw products
or poor personal hygiene of food handlers.
The foodborne bacterium that causes the largest number of
illnesses in the United
States is Salmonella. Salmonella is found in the GI tract and
feces of animals and in eggs. Most
people infected with Salmonella experience diarrhea, fever, and
abdominal cramps within
12–72 hours after eating the infected food. The illness usually
lasts 4–7 days. People in
generally good health before becoming infected usually recover
without treatment, but
Salmonella infection is the most common cause of foodborne

illness that results in hospi-
talization and death in the United States.10
One type of foodborne bacterium that is not as common, but is
of particular
concern, is Escherichia coli O157:H7. Although most strains of
E. coli are benign, E. coli
O157:H7 secretes a toxin that results in severe, even life-
threatening illness for some
individuals. E. coli O157:H7 intoxication can cause hemolytic
uremic syndrome
(hemo = blood, lyti = destroyed, uremic = too much urea in
blood), which results in
the destruction of red blood cells and damage to and eventual
failure of the kidneys.11
Contaminated ground beef has been the culprit behind most
cases of foodborne illness
caused by E. coli O157:H7. Because bacteria live in the GI
tracts of healthy cattle, they can
easily come into contact with the meat of the animal during
slaughtering and then get
mixed in when the beef is being ground. E. coli is destroyed by
heat, and most outbreaks
occur when people eat undercooked meat, unpasteurized milk,
or raw produce contami-
nated with the bacterium.
norovirus Most common type of virus
that causes foodborne illness; can cause
gastroenteritis, or the “stomach flu.”
bacteria Single-celled microorganisms
without an organized nucleus. Some are
benign or beneficial to humans, whereas
others can cause disease.

hemolytic uremic syndrome Rare condition
that can be caused by E. coli O157:H7 and
results in the destruction of red blood cells and
kidney failure. Very young children and older
adults are at a higher risk of developing this
syndrome.
Viruses, such as the hepatitis A virus, need a
host to survive and multiply.
E. coli O157:H7 is a toxin-producing strain of
Escherichia coli that can cause severe and
even fatal foodborne illness. Most other forms
of E. coli are harmless.
Sustainability
Molds
Molds are multicellular fungi that form a filamentous growth
and thrive on damp
surfaces. Spores give mold the color you see, and when airborne
they spread very eas-
ily. Some molds cause allergic reactions and respiratory
problems. A number of molds
grow on foods such as breads, cheeses, and fruits, and not all of
them are detrimental;
some are used to make certain cheeses like Roquefort, blue,
Gorgonzola, and Brie.
Molds flourish in foods such as breads made without
preservatives because they prefer
warmer temperatures and thrive at room temperature. Molds
also grow on fruits and
vegetables and in the refrigerator on jams, jellies, and even

cured, salty meats, given
enough time.
Some molds in the right conditions produce mycotoxins that can
lead to food intoxi-
cation if ingested. One example of this is aflatoxin, a
carcinogen sometimes found on
moldy peanuts. To avoid mold growth in peanuts and other
legumes, store them in a dry
environment; avoid eating any legumes that have an off color.
Many countries, including
the U.S., monitor foods for aflatoxin. Because of their
visibility, molds are easy to identify
and food that is moldy should be discarded. Cooking and
freezing stop mold growth but
do not kill the toxins present.12
Parasites
Parasites are small organisms, occasionally in the egg or larval
phase, that take their
nourishment from hosts. They can be found in food and water
and are often transmitted
through the fecal-to-oral route.13 Foodborne illness caused by
parasites is much less com-
mon in the United States than is illness caused by other types of
pathogens.14
The most common parasitic illness outbreaks in the United
States have been caused
by just a few types: Cryptosporidium parvum, Cyclospora
cayetanensis, Giardia lamblia, and
Trichinella spiralis. Both Cryptosporidium parvum and
Cyclospora cayetanensis can be found in
contaminated water or food sources. Giardia lamblia is one of
the most common sources
of waterborne illness. Hikers who drink unfiltered water from

streams or lakes often
become infected with the Giardia parasite. Trichinella spiralis
(see photo) is an intestinal
worm whose larvae (hatched eggs) can travel from the digestive
tract to the muscles of
the body. See Table 20.1 for a summary of these parasites and
the foodborne illnesses
they cause.
Prions
A prion is an infectious agent composed of an incorrectly folded
protein particle. Pri-
ons are responsible for diseases known as spongiform
encephalopathies, such as bovine
spongiform encephalopathy (BSE, or mad cow disease) in cattle
and variant Creutzfeldt-
Jakob disease (vCJD) in humans. All known prion diseases
affect the structure of neural
tissue and are untreatable. Cattle and other ruminant animals
develop the disease after
consuming feed that contains prion-containing tissues of
infected animals. Humans can
be infected by consuming the meat or brain tissue of infected
livestock.
Great Britain experienced an outbreak of BSE in the 1990s that
resulted in vCJD
in 150 people. Since that time, the United States has taken
specific steps to protect its
citizens against beef contaminated with BSE, such as limiting
imported meat from coun-
tries at risk for BSE and banning ruminant feed containing
mammalian protein.15 BSE
has not been eradicated, but the incidence of infection is
sporadic and rare, and no one
is known to have developed vCJD because of eating infected

meat in the United States.
Since 2003 there have been only four cases of BSE reported in
the U.S. cattle supply,
the most recent being in 2012.16 In a press briefing, the
USDA’s chief veterinary officer
said the cow’s meat did not enter the food supply and the
carcass was destroyed, so the
risk to human health was minimal.17 The World Organization
for Animal Health (OIE)
recently upgraded the United States’ risk classification for BSE
from controlled risk to
negligible risk.18
molds Microscopic fungi that live on plant and
animal matter; some can produce mycotoxins,
which are harmful.
parasites Organisms that live on or in another
organism; obtain their nourishment from their
hosts.
prion Short for proteinaceous infectious
particle; self-reproducing protein particles that
cause degenerative brain diseases.
The parasitic roundworm Trichinella spiralis.
Some Illnesses Are Caused by Natural Toxins
Many toxins that occur in plants and animals function as natural
pesticides and assist
in fending off predators. In many cases, these natural toxins are
present in amounts too

small to harm humans, but there are instances in which these
naturally occurring toxins
can make a person seriously ill.
Marine Toxins
Cooking fish thoroughly may or may not destroy naturally
occurring marine toxins. Eat-
ing spoiled finfish, such as tuna and mackerel, can cause
scombrotoxic fish poisoning,
in which the spoilage bacteria break down proteins in the fish
and secrete histamine, a
toxin that can accumulate to harmful levels. Consuming fish
that contain large amounts
of histamine can cause symptoms such as diarrhea, flushing,
sweating, and vomiting
within 2 minutes to 2 hours.19
Large, predatory reef fish, such as barracuda and grouper, can
sometimes be con-
taminated with ciguatoxins, which when eaten can cause
ciguatera poisoning. In this
case, toxins travel through the food chain and bioaccumulate in
larger species (see
Figure 20.1). Ciguatoxins originate in microscopic sea
organisms called dinoflagellates,
which are eaten by small tropical fish, which in turn are eaten
by larger fish. When people
consume the larger fish, the consumption of the accumulated
concentrations of toxin
can result in illness.20 In addition to experiencing various
gastrointestinal discomforts,
individuals infected with ciguatera may have temperature
sensation reversal in their mouth
when they eat.21 For example, hot liquids and hot foods feel
cold, and vice versa.

Marine neurotoxins can contaminate certain shellfish, such as
mussels, clams, scal-
lops, oysters, crabs, and lobsters, that typically live in the
coastal waters of New England
and the Pacific states. Neurotoxins are also produced by a
particular reddish-brown-
colored dinoflagellate. These reddish-brown dinoflagellates can
become so abundant that
the ocean appears to have red streaks, also known as red tides.
Eating shellfish contami-
nated with neurotoxins can lead to paralytic shellfish poisoning.
Symptoms include
mild numbness or tingling in the face, arms, and legs, as well as
headaches and dizziness.
In severe cases muscle paralysis, the inability to breathe, and
death could result.22
Toxins in Other Foods
Many plant foods naturally contain toxins in small amounts and
don’t generally pres-
ent problems when eaten in reasonable portions; however,
consuming them in large
amounts could be harmful. For example, potatoes that have been
exposed to light can
marine toxins Chemicals that occur naturally
and contaminate some fish.
scombrotoxic fish poisoning Condition
caused by consuming spoiled fish that contain
large amounts of histamines; also referred to
as histamine fish poisoning.
ciguatera poisoning Condition caused
by marine toxins that are produced by
dinoflagellates and have bioaccumulated in fish

that the affected person consumes.
bioaccumulate To build up the levels of a
substance or chemical in an organism over
time, so that the concentration of the chemical
is higher than would be found naturally in the
environment.
paralytic shellfish poisoning Condition
caused by a reddish-brown-colored
dinoflagellate that contains neurotoxins.
▲ Figure 20.1 Bioaccumulation of Toxins
Dinoflagellates
produce toxin and/or
other microscopic
organisms become
contaminated with toxins.
Level 1 Small fish eat the
dinoflagellates. Over time,
the toxins accumulate and
become more concentrated
in their bodies.
Level 2 Large,
predatory fish consume
the smaller contaminated
fish, which increases
their toxin concentration.
Level 3 Fishermen catch
the larger fish for human
consumption.

Level 4
Increasing accumulation of biotoxins equals bioaccumulation
Sustainability
develop a green tinge on the surface, which indicates that they
contain increased amounts
of solanine, a toxin that can cause fever, diarrhea, paralysis, and
shock. Peeling pota-
toes and removing the green layer ensures that the potato can be
safely eaten. Eating
2–5 milligrams of solanine per kilogram of body weight results
in symptoms and eat-
ing 3–6 milligrams of solanine per kilogram of body weight may
result in death.23 The
amount of solanine in potatoes is very small, on the order of
about 0.2 milligrams per
gram of potato. Eating approximately 1 pound of green potatoes
would likely make a
100-pound person ill.
However, other foods contain toxins that are harmful even in
trace amounts, and so
should be avoided altogether. Certain wild mushrooms, for
example, are poisonous; they
contain toxins that can cause nausea and vomiting, liver
damage, and death.
Chemical Agents Sometimes Cause Foodborne Illness
Consumers are becoming increasingly concerned about
environmental damage caused
by industrial and household chemicals. Traces of these

substances can travel through the
food chain and be ingested by people, posing numerous risks to
health. Awareness of the
potential environmental and health risks caused by these
chemicals has led to a search
for safer alternatives.
Polychlorinated Biphenyls
Polychlorinated biphenyls (PCBs) are industrial pollutants that
occur in the food sup-
ply. These chemicals were used as coolants and insulating fluids
for transformers and
capacitors, as flame-retardants, and in the manufacture of
plasticizers, waxes, and paper.
Production of PCBs was banned in 1979 due to their high
toxicity and persistence—
resistance to being broken down—in the environment.24
PCB exposure in adults can cause skin conditions such as acne
and rashes as well
as liver damage. It is of particular concern for pregnant and
lactating women because
prenatal exposure and consumption of contaminated breast milk
can damage a child’s
nervous system and cause learning defects. Also, because young
children are smaller,
exposure to PCBs has a proportionately greater effect on them
than would the same level
of exposure in adults. Moreover, exposure to PCBs can cause
cancer in animals and may
be carcinogenic in humans.25
Although PCBs are no longer manufactured in the United States,
they do not degrade
and can therefore still make their way into the environment
through releases from hazard-

ous waste sites, the burning of commercial or municipal waste,
and the improper disposal
of consumer products, such as old television sets and electrical
fixtures and devices.26
PCBs in the air eventually return to our land and water by
runoff in snow and rain and
may bioaccumulate in larger predatory fish that live in polluted
waters (see Figure 20.1).27
The EPA began regulating PCBs in drinking water in 1992, and
the agency is work-
ing to lower the amount of PCBs in the environment.28
Although the FDA routinely
monitors PCB levels in the food supply, the toxin can be found
in nonregulated food
sources, such as locally caught fish. Consumers should
therefore research and adhere to
local fish consumption advisories. See the Table Tips for the
EPA website that lists cur-
rent advisories, as well as tips to minimize exposure to toxins
and chemical agents in fish
and seafood.
Methylmercury
Mercury occurs naturally, but is also produced as an industrial
by-product or pollutant.
An airborne form of mercury can accumulate on the surface of
streams and oceans and
be transformed by the bacteria in the water into the toxic form
of methylmercury. Meth-
ylmercury toxicity is associated with nervous system damage in
adults and impaired neu-
rological development in infants and children.29 Methylmercury
may bioaccumulate in
solanine Toxin found in potato surfaces

exposed to light that can cause fever, diarrhea,
and shock if consumed in large amounts.
polychlorinated biphenyls (PCBs) Synthetic
chemicals that have been shown to cause
cancer and other adverse effects on the
immune, reproductive, nervous, and endocrine
systems in animals; may cause cancer in
humans.
TABLE TIPS
Avoid Toxins and Chemical
Agents in Seafood
Keep fish, especially finfish—such as
fresh tuna, mackerel, grouper, and
mahi mahi—chilled in the refrigerator to
prevent spoilage and the formation of
histamine toxins.
Never consume finfish or shellfish that
is sold as bait, as these do not meet
food safety regulations.
Observe all fish consumption
advisories. To learn if an advisory is in
place for the fish in your area, search
for “Fish Consumption Advisories” at
www.epa.gov.
If you fish recreationally, always
check with the local or state health
department for specific advice based
on the local waters to avoid eating
PCB-containing fish.

Eat a variety of types of fish to minimize
the exposure to a particular toxin.
Source: Adapted from Centers for Disease
Control and Prevention. 2016. Harmful Algal
Bloom (HAB)-Associated Illness. Available at
https://www.cdc.gov/habs/illness-symptoms-
marine.html; Agency for Toxic Substances and
Disease Registry. Updated 2014. ToxFAQ for
Polychlorinated Biphenyls (PCBs). Available
at https://www.atsdr.cdc.gov/toxfaqs/
tf.asp?id=140&tid=26.
What Strategies Can Prevent Foodborne Illness? 739
fish, seafood, and other wildlife and cause toxicity to humans if
consumed in sufficient
quantities. Larger fish—including shark, swordfish, king
mackerel, and tilefish—contain
high levels of mercury, so the FDA and EPA recommend that
women who are or may
become pregnant, women who are nursing, and young children
should avoid consuming
these fish.30
Some People Are at Higher Risk for Foodborne Illness
Older adults, young children, pregnant women, and people with
certain disorders have
compromised immunity. They are therefore more susceptible to
contracting foodborne
illness and suffering complications than the rest of the
population.

Age-related deterioration of the immune system increases the
risk for foodborne ill-
ness. In addition, because the level of acidic gastric juice
produced by the stomach declines
with age, fewer foodborne pathogens are destroyed in the
stomach. This puts older adults
at higher risk of serious disease and death from foodborne
illness.31 As the percentage
of Americans 65 years of age and older increases—it is
projected to reach 21.7 percent
by the year 2040—more Americans will be at higher risk for
severe foodborne illness.32
In addition to age, any condition that weakens a person’s
immune system, such as
HIV, AIDS, cancer, or diabetes, can increase the risk of serious
foodborne illness.33 Also,
the hormonal shifts that occur during pregnancy can weaken a
pregnant woman’s immune
system, making her more vulnerable to a potentially life-
threatening illness caused by the
bacterium Listeria monocytogenes. (See Spotlight: The
Lowdown on Listeria.)
Individuals in institutional settings (such as nursing homes,
hospitals, schools, and
on cruise ships), where groups of people eat foods from the
same source, are also at higher
risk of foodborne illness. Improper food handling and poor
hygiene practices of foodser-
vice workers are often the causes of foodborne disease
outbreaks in institutional settings.
LO 20.1: THE TAKE-HOME MESSAGE Foodborne illness is a
serious public
health problem. Consuming pathogens in contaminated food or

drinks causes
foodborne infection, whereas consuming toxins causes
foodborne intoxica-
tion. Viruses and bacteria are the most common causes of
foodborne infection
in the United States, although parasites and prions can also
cause foodborne
illness. Toxins can be released into foods by bacteria or can
occur naturally
in foods such as mushrooms or as the result of bioaccumulation
of industrial
chemicals such as polychlorinated biphenyls (PCBs) and
methylmercury. Cer-
tain populations, including older adults, children, pregnant
women, and those
with compromised immune systems, are at higher risk of
contracting foodborne
illness and suffering complications.
What Strategies Can Prevent
Foodborne Illness?
LO 20.2 Summarize strategies to prevent foodborne illness in
the home and
when traveling.
One of the best ways to prevent foodborne illness is to keep the
pathogens that cause
it from flourishing in foods. For example, in order for bacteria
to thrive and multiply,
they must have the proper conditions. These include (1) a
source of nutrients (including
glucose, amino acids, or vitamins and/or minerals), (2)
moisture, (3) a pH above 4.6 (con-
sidered low acidity), (4) temperatures in the range of 40–140°F
(4.4–60°C), and (5) time

(at least 20 minutes) to multiply.34 Protein- and nutrient-rich
animal-based foods, such as
Sustainability
The Lowdown on ListeriaSPOTLIGHT
Listeriosis, the illness caused by the bacterium Listeria
monocytogenes, seriously affects approximately
1,600 individuals in the United Sates
annually, with pregnant women being
10 times more likely than other people
to become infected.1 Listeria can reach
the fetus through the placenta, be trans-
mitted to the developing fetus, and lead
to severe illness, premature birth, mis-
carriage, and stillbirth. Older adults and
those with a weakened immune system
are also at risk for becoming very sick
or even dying.
Animals can harbor Listeria, which
leads to contamination of meat and
dairy foods. Pasteurization kills Listeria,
so unpasteurized soft cheeses, such as
Camembert, Brie, and blue cheeses,
carry a higher risk of contamination.
Compared with hard cheeses such
as Parmesan, these soft cheeses are
less acidic and contain more moisture,
two conditions that enhance bacte-
rial growth. Even though cooking can
also destroy Listeria, the lower cooking

temperature used during the process-
ing of soft cheeses isn’t high enough
to destroy this bacterium. Because
contamination can also occur after
processing, many outbreaks have been
associated with other foods such as
hot dogs, deli-style luncheon meats,
salami, and paté. Listeria can also
continue to multiply at refrigerated
temperatures.
The following tips can help pregnant
women and other higher-risk individu-
als reduce their likelihood of contracting
Listeria:2,3
• Heat ready-to-eat luncheon meats,
cold cuts, fermented and dry sausage,
deli-style meat and poultry products,
and hot dogs until they are steamy
hot to kill any existing bacteria before
serving.
• Wash your hands with hot, soapy
water after touching these types of
ready-to-eat foods, or any foods for
that matter. Also thoroughly wash cut-
ting boards, dishes, and utensils.
• Avoid soft cheeses such as feta,
Brie, Camembert, blue-veined (blue)
cheese, and Mexican-style cheeses
unless they are made with pasteurized
milk. (Read the ingredients list to see

if pasteurized milk was used.) You can
safely eat hard cheeses, semi-soft
cheese such as mozzarella, pasteur-
ized processed cheeses, cream
cheese, and cottage cheese.
• Avoid unpasteurized milk and foods
made from unpasteurized milk.
• Avoid refrigerated smoked seafood
such as smoked salmon (lox or nova
style), trout, whitefish, cod, tuna, or
mackerel unless they are used in an
entrée such as a heated casserole.
You can safely eat canned fish and
shelf-stable smoked seafood.
• Avoid refrigerated paté or meat
spreads. You can safely eat canned or
shelf-stable varieties.
• Eat precooked or ready-to-eat
perishable items before the expiration
date on the food label.
References
1. Centers for Disease Control and Prevention.
2016. Listeria (Listeriosis). Available at
www.cdc.gov/listeria. Accessed April
2017.
2. Ibid.
3. USDA. 2016. Fact Sheets: Protect Your Baby and
Yourself from Listeriosis. Available at https://

www.fsis.usda.gov/wps/portal/fsis/top-
ics/food-safety-education/get-answers/
food-safety-fact-sheets/foodborne-illness-
and-disease/protect-your-baby-and-yourself-
from-listeriosis/CT_Index. Accessed April
2017.
Unpasteurized soft cheese can be contami-
nated with Listeria.
raw and undercooked meat, poultry, seafood, eggs, and
unpasteurized milk, are the most
common types of foods that provide conditions for rapid
bacterial growth.
Bacteria thrive in moist environments, such as in raw chicken
that is sitting in its
juices. Dry foods, such as uncooked rice, sugar, flour, and
cereals, do not usually support
bacterial growth until they are hydrated with a liquid. However,
infected utensils or hands
can contaminate these foods. For example, a person with
infected hands who takes a
handful of cereal directly out of the box transfers bacteria onto
the cereal. Although the
bacteria may not multiply, they survive and, once eaten, will
grow in the moist environ-
ment of the GI tract, possibly resulting in foodborne illness.
Bacteria don’t thrive in acidic foods (pH less than 4.6) such as
vinegar and citrus fruits,
so these foods seldom provide the conditions necessary for
growth. However, animal-based
foods have a higher pH and provide the right conditions for
bacteria to flourish.

Bacteria multiply most abundantly between the temperatures of
about 40°F and
140°F. At body temperature, or 98.6°F (37°C), bacteria can
divide and double within
20 minutes and multiply to millions in about 12 hours.35
Because bacteria need such a short
time period to multiply, it is important to realize that perishable
food, such as raw meat,
left at room temperature for an extended period can become a
feast for bacterial growth.
Consumers can take various measures when consuming and
handling food to reduce
the risk of foodborne illness. These include preventing the
growth of bacteria and destroy-
ing any pathogens that may be present. This can be done
through the consistent practice
of proper food consumption, handling, and storage strategies at
home and while traveling.
Practice Food Safety at Home
An easy way to remember the important points of home food
safety is by focusing on
the “Core Four” of the Fight BAC! campaign of the nonprofit
Partnership for Food
Safety Education: Cleaning, Combating cross-contamination (or
separating), Cooking,
and Chilling (Figure 20.2).36
Clean Hands and Produce
Cleaning is one of the simplest ways to reduce the chances of

microbial contamination,
and proper handwashing is one of the most important overall
strategies for preventing
foodborne illness. If everyone practiced proper handwashing
techniques, the incidences
of foodborne illness could decrease by about half.37 The Table
Tips summarize proper
handwashing techniques.
Proper handwashing refers to washing hands thoroughly, as well
as washing hands
regularly. This last part, regular washing, is where many people
fall short. Germs accumu-
late on hands from a variety of sources throughout the day, and
if hands are not regularly
washed, these germs can infect the body after being passed into
the mouth, nose, and eyes.
Individuals also spread the germs to others by touching surfaces
such as doorknobs.38
In instances where handwashing is not an option, such as when
traveling or
eating on the run, using disposable wipes or hand gel sanitizers
can be an excellent
TABLE TIPS
Wash Your Hands!
After using the toilet
After changing a diaper
After touching animals
Before and after food preparation,

especially when handling raw meat or
poultry
After blowing your nose
After coughing or sneezing into your
hands
Before and after treating wounds
After handling garbage
Before inserting or removing contact
lenses
Proper handwashing:
Wet hands with warm, running water
and apply liquid soap or use clean bar
soap. Lather well.
Rub hands together vigorously for at
least 20 seconds (recite the alphabet
twice or sing “Happy Birthday” twice).
Scrub all surfaces, including the backs
of hands, wrists, between fingers, and
under fingernails.
Rinse well.
Dry hands with a clean cloth towel or
disposable towel.
Use a towel to turn off the faucet and, if
in a public restroom, use a clean towel

to open the door as well.
Source: Adapted from Mayo Clinic. 2016.
Hand Washing: Do’s and Don’ts. Available at
www.mayoclinic.org/healthy-lifestyle/adult-
health/in-depth/hand-washing/art-20046253.
Accessed April 2017.
▲ Figure 20.2 Fight BAC!
The Fight BAC!® symbol sums up the “Core Four” of keeping
food safe in the kitchen: clean,
combat cross-contamination (separate meats from ready-to-eat
foods), cook thoroughly, and
chill to a cold enough temperature.
Source: www.fightbac.org/food-safety-basics/the-core-four-
practices/
Sustainability
alternative. Only the alcohol-based products are effective in
killing germs. The
Centers for Disease Control and Prevention (CDC) recommends
choosing products
that contain at least 60 percent alcohol.39 Individuals should
keep hand sanitizers in
the car, purse, desk drawer, and backpack so that proper hand
hygiene can be practiced
at all times.40
In addition to hands, anything that touches food, such as knives,
utensils, and coun-
tertops, should be thoroughly cleaned between each use. Cutting
boards should be placed

in the dishwasher or scrubbed with hot, soapy water and rinsed
after each use. Nonporous
cutting boards made of plastic, marble, and tempered glass are
easier to keep clean than
the more porous wooden cutting boards or wooden surfaces.
Cracked cutting boards
should be discarded, as they can harbor pathogenic microbes.
Kitchen sinks and cutting
boards should be regularly sanitized by filling the sink with hot
water and adding one
teaspoon of bleach per quart of water. Let the board sit in the
sanitizing liquid for a few
minutes to kill the microbes, then rinse it thoroughly.
A kitchen sponge is an ideal environment for bacteria because it
provides the ideal
temperature, moisture, and nutrients (food particles). Household
kitchen sponges and
dishcloths have been shown to harbor more bacteria than toilet
seats.41 Consequently,
sponges and dishcloths need to be replaced often and between
replacements washed after
each use in the hot cycle of the washing machine, preferably
with bleach in addition to
soap. They can also be soaked in a bleach solution along with
the cutting boards, run
through the dishwasher (including the dry cycle), or placed in
the microwave for 1 minute
at its highest setting.42 To avoid fire hazards, be sure to use the
microwave method only
with damp sponges and those without metal.
All fruits and vegetables should be thoroughly washed under
running tap water
before eating. Even foods like cantaloupe, which doesn’t have
an edible peel or rind,

have been known to carry Salmonella and E. coli, and the
microbe can be transferred from
the peel or rind to the fruit by the knife used to cut it open.
Washing firm fruit with a
vegetable brush helps remove any dirt or microbes on its
surface. Fruit should be cut only
on a clean cutting board. Washing fruits and vegetables offers
the additional advantage
of removing most of the pesticide residue that may be present.
Pesticides are discussed in
more detail later in this chapter.
Combat Cross-Contamination
Cross-contamination is the spread of microbes from one item to
another. It can occur,
for example, when washed lettuce—which is going to be eaten
raw—comes into contact
with raw meat, poultry, or fish during food preparation. To
avoid cross-contamination
between animal-based foods and fresh bread or raw fruits and
vegetables, maintain sepa-
rate cutting boards for meat and nonmeat foods. If you have just
one cutting board, wash
it thoroughly in hot, soapy water immediately after use.
Also, when grocery shopping, raw meats, fish, and poultry
should be bagged sepa-
rately from produce. Once home, these foods should either be
frozen or stored in airtight
containers on the bottom shelf of the refrigerator. This prevents
contaminated drippings
from coming in contact with cooked foods or raw fruits and
vegetables. Marinades that
are used to tenderize and flavor raw meats, poultry, or fish
should never be reused as a
basting or serving sauce. All plates and bowls that have

contained raw meats, poultry, and
fish should be thoroughly washed before reuse. For example, at
a barbecue, the plate that
held the raw hamburgers should never be used to serve the
cooked burgers unless it has
been thoroughly washed.
Another common source of cross-contamination occurs when
soiled dishtowels are
used to dry clean hands, dishes, or utensils. A towel that was
used to wipe up raw meat
juices or your hands can transfer those microbes to your clean
dishes or utensils. You could
easily coat those clean surfaces with a layer of germs. Figure
20.3 summarizes some of the
ways to combat cross-contamination in the kitchen.
cross-contaminate Transfer of pathogens
from a food, utensil, cutting board, kitchen
surface, and/or hands to another food or
object.
The countertop sponge may very well be the
most contaminated item in your kitchen. Food
scraps, moisture, and room temperature
can lead to a thriving bacterial colony on this
common cleaning item.
Cook Foods Thoroughly
A common food safety misconception is that meat that looks
brown is fully cooked.
Look at the two hamburger patties in Figure 20.4. The brown

patty on the bottom
might look more thoroughly cooked than the pinker patty above,
but it’s not. The color
of beef is largely determined by myoglobin, the iron-containing
protein that provides
the purplish-red pigment in meat (and in human muscle tissue).
The denaturing of this
protein is what causes meat to turn from pink to brown during
cooking. However, if
the meat starts out brown, this color change won’t occur. Thus,
a burger could look
“done” when it may still be raw in places. Research has shown
that hamburgers can look
“well done” while only having reached an internal temperature
of approximately 135°F
(57.2°C).43 Ground meat (beef, pork, veal, and lamb) must
reach an internal tempera-
ture of 160°F (71.1°C) to kill pathogens known to cause illness.
In contrast, some lean
or treated varieties of beef can remain pink even though they
have reached an internal
temperature of 160°F.
Poultry color can also be misleading because it can remain pink
after thorough cook-
ing. This is caused by a chemical reaction that occurs in the
poultry from gases in the oven
that give the meat a pink tinge. Because younger birds have thin
skins, the gases can react
with their flesh more easily and make the meat look pinker than
that of older birds. Also,
nitrates and nitrites added to some poultry as a preservative can
give poultry a pink tinge
(see the discussion of food additives later in the chapter).44
The only way to determine if food has reached an internal

temperature high enough
to kill pathogens is to use a food thermometer. Figure 20.5
shows several types of food
thermometers available for use when cooking. Table 20.2
provides a list of the internal
temperatures that foods should reach to ensure that they are safe
to eat.
myoglobin Protein that provides the purplish-
red color in meat and poultry.
Do store raw meats
separate from and
ideally below produce
and cooked foods.
Don’t reuse the marinade
unless it has been boiled.
Don’t use dirty towels
to dry clean dishes.
Do discard worn cutting
boards with lots of cuts
and scratches.
Do wash utensils, countertops,
and cutting boards thoroughly
with hot soapy water after
they touch raw meat, fish,
or poultry.
Do sanitize sponges and
cutting boards with
chlorine bleach solution.

Do use separate designated
cutting boards for meats
and vegetables.
Do marinate raw meat
in the refrigerator in
sealed containers.
▲ Figure 20.3 The Do’s and Don’ts of Avoiding Cross-
Contamination
▲ Figure 20.4 Cook Meats Thoroughly
to Kill Pathogens
A hamburger needs to reach an internal tem-
perature of 160°F to ensure that all foodborne
pathogens are killed. Color is not an indication
of “doneness.”
a
b Cooked to internal temperature of 135°F
Cooked to internal temperature of 160°F
Sustainability
▲ Figure 20.5 Food Thermometers
There are several types of food thermometers available for
measuring the internal temperature
of cooked foods. The thermometer should be inserted at least
one-half-inch deep into the food
and should be washed thoroughly after each use and before
insertion into any food.

Thermometer fork combination
thermometers allow you to stab and
check. A device that measures the
temperature in the food is located in
the tines of the fork.
Thermocouple digital food
thermometer displays the temperature
of the food within 6 seconds after
placement.
Thermistor digital food thermometers
take approximately 10 seconds to
display the temperature of the food on
the dial.
Oven-safe bimetallic-coil
thermometers are most useful when
cooking thick foods such as roasts and
turkeys. They are unique, as they can
stay in the food during cooking.
If You Are Cooking
This Food
The Food
Thermometer
Should
Reach (°F)*
Ground Meat and Meat Mixtures
Beef, pork, veal,
lamb

160
Turkey, chicken 165
Fresh Beef, Veal,
Lamb
145**
Poultry
Chicken, turkey,
whole or parts
165
Duck and goose 165
Fresh Pork
Ham, raw 145**
Ham, precooked (to
reheat)
140
Fish and Shellfish 145
Eggs and Egg Dishes
Eggs Cook until yolk
and white are firm
Egg dishes 160

Leftovers and
Casseroles
165
*The thermometer should be placed in the thickest
part of the food item.
**Meat should rest for 3 minutes before consumption
to ensure that pathogens are destroyed.
Sources: Adapted from USDA Food Safety and
Inspection Service. 2015. Kitchen Thermometers.
Available at https://www.fsis.usda.gov/wps/portal/
fsis/topics/food-safety-education/get-answers/food-
safety-fact-sheets/appliances-and-thermometers/
kitchen-thermometers/ct_index. Accessed April 2017;
USDA Food Safety and Inspection Service. 2016.
Keep Food Safe! Food Safety Basics. Available at
https://www.fsis.usda.gov/wps/portal/fsis/topics/food-
safety-education/get-answers/food-safety-fact-sheets/
safe-food-handling/keep-food-safe-food-safety-
basics/ct_index. Accessed April 2017.
TABLE 20.2 Safe Food
Temperatures
Chill Foods at a Low Enough Temperature
Proper chilling and refrigeration of foods is essential to inhibit
the growth of pathogens.
But just how low must the temperature be? Foodborne bacteria
multiply most rapidly
in temperatures between 40° and 140°F (or 4.4–60°C), a range
known as the “danger
zone.” To keep foods out of the danger zone, hot foods must be
kept hot, above 140°F,
and cold foods kept cold, below 40°F, or even lower (see Figure

20.6). This means that
when cooked foods like lasagna are on a buffet table, they
should be sitting on a hot plate
or other heat source that keeps their temperature above 140°F,
while cold prepared foods
such as potato salad should be kept at 40°F or below at all
times.45
Refrigerating foods for storage is another key aspect of keeping
them chilled and
inhibiting the growth and reproduction of pathogenic microbes.
With the exception of the
Listeria bacterium, cold temperatures slow down microbes’
ability to multiply to dangerous
levels; note that chilling does not kill them or completely stop
their growth. To ensure that
the growth of microbes on foods is controlled, refrigerator
temperatures should be set at
or below 40°F (4.4°C). The temperature for the freezer should
be set at 0°F (-17.7°C)
or below. Food stays safe in the freezer indefinitely, though its
quality may deteriorate.
“Freezer burn” may occur if frozen food is not tightly wrapped
and gets exposed to air.
Freezer burn causes the texture of food to change, as it dries out
and accumulates ice
crystals. This results in a less pleasant taste and appearance, but
it isn’t harmful. Most
microbes become dormant and are unable to multiply when they
are frozen, but they
aren’t destroyed. When food is defrosted the microbes can
multiply again under the right
conditions.
Two hours is the critical time to remember. Perishables such as
raw meat and poultry

left out at room temperature (a temperature within the danger
zone) for more than 2 hours
may not be safe to eat. In temperatures above 90°F (32.2°C),
such as in the kitchen in the
summertime, foods shouldn’t be left out at room temperature for
more than 1 hour.46
Leftovers should be refrigerated within 2 hours of being
prepared. Large roasts and pots
of soup or stews should be divided into smaller batches and
placed in shallow containers
in order to cool more quickly in the refrigerator. If these items
have been left in the danger
zone for too long, bacteria can grow and may also produce
toxins that are heat resistant.
danger zone Range of temperatures between
40° and 140°F at which foodborne bacteria
multiply most rapidly; room temperature falls
within the danger zone.
These toxins are not destroyed even if the food is cooked to a
proper internal temperature
and could cause illness if consumed.47
Once food is refrigerated it shouldn’t be held for more than a
few days, even when
kept at the proper temperature. A good rule of thumb is that
leftovers can be in the refrig-
erator at 40°F or below for no more than 4 days. Remember,
after 4 days in the refrigera-
tor, leftovers are ready for disposal. Raw meats, poultry, and
seafood can be safely kept

in the refrigerator for a maximum of 2 days. A good food safety
strategy is the acronym
FIFO, which means “first in, first out.” In other words, use food
that has been in the
refrigerator the longest first. Table 20.3 lists the storage times
for various foods. Don’t
eat food that you suspect may not be safe. If you are unsure
about the safety of a food,
remember this rhyme: When in doubt, throw it out.
Minimizing the risk for developing a foodborne illness requires
a conscious effort
to clean, avoid cross-contamination, cook, and chill to keep
foods safe. Think about how
many of these strategies you use in your own kitchen and use
the Self-Assessment to help
identify areas in which you may need to improve your food
safety habits.
▲ Figure 20.6 The Danger Zone
Bacteria multiply rapidly in the “danger zone,”
between temperatures of 40° and 140°F.
0°
40°
68°
170°
160°
145°
140°

165°
Well-done meats
Medium-done
meats, raw eggs,
egg dishes, pork,
ground meats
Medium-rare beef
steaks, roasts,
veal, lamb
Stuffing, poultry,
reheated leftovers
Safe zone
(above
140°)
Hold hot foods
Do not keep foods
between 40°F
and 140°F for
more than 2 hours
or for more than
1 hour when the
air temperature is
greater than 90°F
Room
temperature
Refrigerator

temperatures
Freezer
temperatures
Safe zone
(below
40°F)
Te
m
pe
ra
tu
re
(F
ah
re
nh
ei
t)
Danger
zone
Product Storage Time after Purchase*
For Raw Foods
Poultry 1 or 2 days

Beef, veal, pork, and lamb 3–5 days
Ground meat and ground poultry 1 or 2 days
Fresh variety meats (liver, tongue, brain, kidneys,
heart, intestines)
1 or 2 days
Cured ham, cook-before-eating 5–7 days
Sausage from pork, beef, or turkey, uncooked 1 or 2 days
Fish 1 or 2 days
Eggs 3–5 weeks
Unopened,
after
Purchase*
After
Opening*
For Processed Product Sealed at Plant
Cooked poultry 3–4 days 3–4 days
Cooked sausage 3–4 days 3–4 days
Sausage, hard/dry, shelf-stable 6 weeks/pantry 3 weeks
Corned beef, uncooked, in pouch with pickling
juices
5–7 days 3–4 days

Vacuum-packed dinners, commercial brand with
USDA seal
2 weeks 3–4 days
Bacon 2 weeks 1 week
Hot dogs 2 weeks 1 week
Luncheon meat 2 weeks 3–5 days
Ham, fully cooked, whole 7 days 3 days
Ham, canned, labeled “keep refrigerated” 9 months 3–4 days
Ham, canned, shelf-stable 2 years/pantry 3–5 days
Canned meat and poultry, shelf-stable 2–5 years/
pantry
3–4 days
Leftovers 3–4 days
*Based on refrigerator home storage (at 41°F [5°C] or below)
unless otherwise stated.
Source: Adapted from USDA Food Safety and Inspection
Service. 2016. Keep Foods Safe! Food Safety Basics.
Available at
https://www.fsis.usda.gov/wps/portal/fsis/topics/food-safety-
education/get-answers/food-safety-fact-
sheets/safe-food-handling/keep-food-safe-food-safety-
basics/ct_index. Accessed April 2017.
TABLE 20.3 Safe Storage of Perishable Foods

Sustainability
Practice Food Safety While Traveling
Travelers should follow food safety procedures to reduce the
risk of illness while trav-
eling abroad. Each year, up to 50 percent of international
travelers are estimated to
have their trips interrupted by foodborne illness.48 One type of
E. coli, enterotoxi-
genic (entero = intestines, toxi = toxin, genic = forming) E.
coli, is a common cause
of traveler’s diarrhea. Traveler’s diarrhea causes watery
diarrhea and gastrointestinal
cramps and is primarily caused by consuming contaminated
food, water, or ice. People
visiting countries where sanitation is poor, including some
developing countries in Latin
America, Africa, the Middle East, and Asia, are at a higher risk
of contracting it.49 See
the Table Tips for suggestions on how to avoid traveler’s
diarrhea and other forms of
foodborne disease while traveling.
traveler’s diarrhea Common pathogen-
induced intestinal disorder experienced by
some travelers who visit areas with unsanitary
conditions.
TABLE TIPS
Avoiding Foodborne Illness
While Traveling

If you are traveling abroad, look up the
country you’re visiting on the Centers
for Disease Control’s National Center
for Infectious Diseases Travelers’ Health
Destination website at www.cdc.gov/
travel/destinat.htm to find out about
any specific health advisories for that
area.
Do not eat raw or undercooked meat
or seafood.
Do not consume raw fruits and veg-
etables unless you wash and peel
them. Thoroughly cooked fruits and
vegetables should be safe to eat.
Do not consume foods from street
vendors or other vendors who appear
to leave food at room temperature for
extended periods of time.
Do not consume food or beverages
from vendors who appear unclean or
have unclean establishments. A clean
environment is no guarantee against
foodborne illness, but unclean environ-
ments are more likely to spread food-
borne illness.
Do not drink tap water or use ice made
from tap water unless it has been
boiled first or treated with iodine or
chlorine. Bottled water should be safe.

Do not consume unpasteurized milk or
other unpasteurized dairy foods.
Source: Adapted from Centers for Disease
Control and Prevention, Division of Bacte-
rial and Mycotic Diseases. 2013. Travelers’
Diarrhea. Available at https://wwwnc.cdc.gov/
travel/page/travelers-diarrhea. Accessed April
2017.
Self-Assessment
How Do Your Food Safety Habits Stack Up?
Take the following quiz to find out.
How Often Do You Always Sometimes Never
Wash your hands before preparing food?
Scrub your fruits and vegetables under cold, running
water before eating them?
Use an insulated pouch with an ice pack to carry
your perishable lunches and snacks, such as meat-
filled sandwiches and/or yogurt and cheese?
Wash your hands after using the bathroom?
Throw out refrigerated leftovers after 4 days?
Chop raw vegetables on a clean chopping board
rather than the one you just used for raw meat, fish,
or poultry?
Use a thermometer to determine if the meat or poul-
try you are cooking is done?

Answer
If you answered “Always” to all of the above you are practicing
superior food safety skills.
If you didn’t, there’s more you can do to reduce your chances of
contracting a foodborne
illness.
LO 20.2: THE TAKE-HOME MESSAGE Proper food handling
and storage
strategies—particularly cleaning, preventing cross-
contamination, cooking to
recommended temperatures—and chilling at recommended
temperatures, can
help reduce the risk of foodborne illness. Anything that comes
in contact with
foods, including hands, should be thoroughly washed, and
produce should
always be washed before eating it. Fresh bread, fruits, and
vegetables need to
be kept separate from raw meats, poultry, and fish and from any
utensils that
touch them. Checking the internal temperature of cooked food
with a food ther-
mometer is the only accurate way to tell if it is safe to eat.
Perishables should
be properly and promptly chilled to minimize the growth of
bacteria. Raw meat,
poultry, and seafood should be used within 2 days. Leftovers
that are refriger-
ated should be discarded after 4 days. Extra caution is needed
when traveling
abroad to avoid foodborne illness.

How Is the Food Supply Protected? 747
How Is the Food Supply Protected?
LO 20.3 Describe how the food supply is protected in the
United States.
The food system includes the techniques and resources involved
in growing, harvesting,
processing, packaging, transporting, selling, and consuming
food. Risks to both food safety
and availability occur at each point in the food system. The
farm-to-table continuum is
a visual tool that shows how farmers, food manufacturers,
transporters, retailers, and you,
the consumer—following regulations and guidelines from the
U.S. government—can help
ensure a safe food supply. Figure 20.7 shows the steps in this
continuum.
farm-to-table continuum Illustrates the
roles that farmers, food manufacturers, food
transporters, retailers, and consumers play in
ensuring that the food supply, from the farm to
the plate, remains safe.
◀ Figure 20.7 The Farm-to-Table
Continuum
Every step in the farm-to-table continuum
plays an important role in reducing microbes
and the spread of foodborne illness.
Farm: Use good agricultural
practices. Farmers grow, harvest,
sort, pack, and store their crops in
ways that help reduce food safety
hazards.

1
Processing: Monitor at critical
control points. During processing,
HACCP measures are implemented.
2
Transportation: Use clean
vehicles and maintain the proper
temperature. Food is kept at a
proper temperature during
transportation to reduce the growth
of foodborne microbes.
3
Retail: Follow the Food Code
guidelines. Retail outlets, including
restaurants, grocery stores, and
institutions (such as hospitals), use
the Food Code guidelines to
reduce the risk of foodborne illness.
4
Consumer: Always follow the
four Cs of food safety (clean,
combat cross-contamination,
cook, chill). The consumer uses
the four Cs to reduce the risk of
foodborne illness.
5

Sustainability
Several Government Agencies and Programs Protect
the Food Supply
In 1906 Congress charged the USDA with the responsibility for
monitoring the safety
of our nation’s food. Today, several federal agencies share the
responsibility for food
safety in the United States.50 Table 20.4 lists these agencies
and summarizes the roles
they each play in safeguarding foods. The Food Safety Initiative
(FSI), begun in 1997,
coordinates the research, inspection, outbreak response, and
educational activities of the
various government agencies.
An example of collaboration among these government agencies
is FoodNet (www.cdc.
gov/foodnet ), which is a combined effort of the CDC, the
USDA’s Food Safety Inspection
Service (FSIS), the FDA, and 10 state health departments. The
program consists of active
surveillance for foodborne diseases and related studies designed
to help public health
officials understand the cause and effect of foodborne diseases
in the United States. The
objectives of the program include determining the burden of
foodborne illness in the
United States, monitoring trends over time, assessing the
incidence of foodborne illness
and its relation to specific foods and settings, and developing
interventions to reduce the
overall burden of foodborne illness.

The CDC coordinates another program called PulseNet
(www.cdc.gov/pulsenet), which
is a national network of public health and food regulatory
agency laboratories—including
those at the CDC, USDA/FSIS, and FDA—designed to identify
and contain foodborne
illness outbreaks. PulseNet participants perform DNA
fingerprinting, a sort of molecu-
lar identification, on pathogenic bacteria. DNA fingerprinting
uses the bacteria’s unique
genetic code to identify different strains of pathogens. These
“fingerprints” are submitted
electronically to a database at the CDC and the information is
available on demand to
public health and food regulatory agencies. Finding similar
strains of a bacterium in both
a person and a food suggests a common source and potential
connection. If similar pat-
terns emerge at the same time in different states, this could
indicate a potential outbreak.
Once a suspicious foodborne illness outbreak is reported and a
source is identified, several
government agencies then work together to contain the disease.
The E. coli outbreak in spinach that occurred in the fall of 2006
is one example of
how multiple government agencies work together to identify and
contain an outbreak. The
CDC, through its monitoring and surveillance programs,
detected an outbreak of illness
due to E. coli O157:H7 and immediately alerted the FDA. DNA
fingerprinting was used
by PulseNet to determine that all infected individuals had
consumed the same strain of
E. coli and to trace the strain to bagged raw spinach grown in

California. The fingerprinting
also allowed the agencies to link the tainted food to reported
illnesses in 26 states. Once
the source of the outbreak was confirmed, the CDC issued an
official health alert about
the outbreak, and the FDA advised consumers to stop eating raw
spinach. Before the
outbreak was over, more than 200 people had been infected, and
more than half of them
Food Safety Initiative (FSI) Coordinates the
research, surveillance, inspection, outbreak
response, and educational activities of the
various government agencies that work
together to safeguard food.
DNA fingerprinting Technique in which
bacterial DNA “gene patterns” (or “fingerprints”)
are detected and analyzed to distinguish
between different strains of a bacterium.
Agency Responsible for
USDA Food Safety and Inspection Service
(FSIS)
Ensuring safe and accurately labeled meat,
poultry, and eggs
Food and Drug Administration (FDA) Ensuring the safety of all
other foods
besides meat, poultry, and eggs
Environmental Protection Agency (EPA) Protecting you and the
environment from
harmful pesticides

Animal and Plant Health Inspection Service
(APHIS)
Protecting against plant and animal pests
and disease
Centers for Disease Control and Prevention Surveillance of
foodborne disease
TABLE 20.4 Agencies that Oversee the Food Supply
had been hospitalized.51,52 Three individuals died and 31
developed hemolytic uremic
syndrome from the outbreak. However, through the
collaborative efforts and swift action
of these federal and state agencies, the outbreak was contained
in a short period of time
and its impact was minimized.
Hazard Analysis and Critical Control Points (HACCP) is a
program used to identify
and control foodborne hazards that may occur in all stages of
the food production pro-
cess.53 The HACCP approach was first conceived in the 1960s
when the U.S. National
Aeronautics and Space Administration (NASA) asked a private
food manufacturer
to design the foods for space flights. Since then, the FDA and
USDA have mandated
HACCP programs for seafood, juice, and meat processing in the
United States. The use

of HACCP is recommended, but not mandated, for other food
industries as well. HACCP
includes seven principles that focus on the analysis of potential
hazards associated with
foods and the identification of critical control points in the
production of a food so that
preventative measures can be put in place to minimize risks. For
example, procedures
for monitoring temperatures throughout a food’s production
need to be in place. Manu-
facturers also apply food preservation techniques to some foods
to make them safer for
consumers. We discuss these techniques later in the chapter.
Issues regarding food safety are also important at retail
establishments. Grocery
stores and restaurants must comply with FDA regulations. The
Food Code is a reference
document published by the FDA that local, state, and federal
regulators use as a model
for the development of their own food safety rules and to be
consistent with national food
regulatory policy. The Food Code provides practical, science-
based guidance, including
HACCP guidelines, and provisions to help purveyors minimize
foodborne illness.54
Food Manufacturers Use Preservation Techniques
to Destroy Contaminants
In addition to government efforts to help prevent foodborne
illness, food manufacturers
also work to safeguard food. Food preservation methods, some
of which have been in
use for thousands of years, include heating, canning, pickling,
salting, drying, and freez-
ing, all of which help to keep foods safe. At the same time,

manufacturers’ use of newer
techniques such as irradiation and chemical additives has
expanded as consumers demand
fast and convenient foods, new flavors, increased shelf-life, and
improved textures.
Pasteurization and Canning
Pasteurization is a process for destroying pathogenic bacteria in
which liquid foods are
heated to a prescribed temperature for a specified time. The
process kills E. coli O157:H7,
Salmonella, and Listeria monocytogenes, all of which can be
present in raw milk. Pasteurization
improves the quality of dairy products and keeps all products
fresh for a longer period of
time. In addition to dairy products, pasteurization is required
for some juices like fresh
apple juice and other foods. Unpasteurized juices must display a
warning on the label to
alert consumers.55
Canning is a process in which foods are packed into airtight
containers and then
heated to temperatures of 240–250°F (115.5–121.1°C) to kill
microorganisms. The
amount of exposure time to heat varies by the type of food, its
acidity, and its density.
Processing conditions are chosen to ensure that the foods are
sterile while retaining the
most nutrients.56
Commercial canning is regulated by the FDA and HACCP
procedures, which virtu-
ally eliminates foodborne illness. However, improperly home-
canned products can be the
source of Clostridium botulinum, one of the toxin-producing

foodborne bacterial species
mentioned earlier in this chapter. C. botulinum can survive in
airless environments and
create spores that are not destroyed at normal cooking
temperatures (refer to Table 20.2
on page 744). A temperature higher than boiling water (212°F
[100°C]) is needed to kill
food preservation Treatment of foods to
reduce deterioration and spoilage and help
prevent the multiplication of pathogens that
can cause foodborne illness.
pasteurization Process of heating liquids
or food at high temperatures to destroy
foodborne pathogens.
spores Hardy reproductive structures that are
produced by certain bacteria and fungi.
canning Process of packing food in airtight
containers and heating them to a temperature
high enough to kill bacteria.
The FDA, CDC, and USDA worked together
to combat an outbreak of E. coli O157:H7 in
2006 that was traced to bagged prewashed
spinach.
Sustainability
these spores.57 Botulism, the foodborne illness caused by
consumption of the botulism

neurotoxin produced by Clostridium botulinum, can be deadly,
as it can cause paralysis of
respiratory and other muscles.58
Two newer preservation methods used to keep foods fresh are
modified atmosphere
packing (MAP) and high-pressure processing (HPP). MAP is a
process during which
the manufacturer modifies the composition of the air
surrounding the food in a package,
thereby extending shelf-life and preserving the quality of
packaged fruits and vegetables.59
HPP is a method in which foods are exposed to pulses of high
pressure that destroy
microorganisms. Foods such as jams, fruit juices, fish, vacuum-
packed meat products,
fruits, and vegetables can be treated with HPP.60
Irradiation
Foods can also be treated with ionizing radiation to kill
pathogenic bacteria and parasites.
During the process of irradiation, foods are subjected to a
radiant energy source within
a protective, shielded chamber called an irradiator. The energy
from the radiant waves
damages the DNA of the pathogens, causing defects in their
genetic instructions. Unless
the microbes can repair the damage, they die. Because
pathogens differ in their sensitivity
to irradiation, the process either kills all of them or greatly
reduces their numbers, thus
reducing the risk of foodborne illness.61 Unfortunately,
irradiation can cause mutations in
some bacteria and viruses and may lead to the development of
irradiation-resistant strains
of these pathogens.62

Irradiation is a cold process and does not significantly increase
the temperature or
change the physical characteristics of most foods, which helps
prevent nutrient loss. Also,
just as foods cooked in a microwave do not retain microwaves,
irradiated foods do not
retain the energy waves used during the irradiation process.63
Most of the irradiating
energy passes through the food and the packaging without
leaving any residue behind.64
Irradiation destroys bacteria such as Campylobacter, E. coli
O157:H7, and Salmonella
and helps control insects and parasites.65 It does not destroy
viruses, such as norovirus
and hepatitis A, or the prions associated with mad cow disease
(BSE). The nucleic acid
of viruses is too small to be destroyed, and prions—which are
protein particles—do not
have nucleic acids.
Irradiation can also stop the ripening process in some fruits and
vegetables and
reduce the number of food spoilage bacteria. Irradiated
strawberries can last up to 3 weeks
in the refrigerator, compared with only a few days for untreated
berries.
Irradiated food has been evaluated for safety by the FDA for
more than 30 years.66
Irradiation has been used for years to sterilize surgical
instruments and implants and to
destroy disease-promoting microbes in foods served to hospital
patients who have weak-
ened immune systems. However, the use of irradiation in foods

is not widespread due to
consumer concerns and the expense of building the facilities.
Since 1986, all irradiated products must carry the international
“radura” symbol,
along with the phrase “treated by irradiation” or “treated with
radiation” on the pack-
age (Figure 20.8). If a product such as sausage contains
irradiated meat or poultry, these
items must be listed as “irradiated pork” or “irradiated chicken”
on the food label.67 A
label is not required if a minor ingredient, such as a spice, has
been irradiated and used
in the product.
Irradiation cannot be used with all foods. It causes undesirable
flavor changes in
dairy products, egg whites tend to become milky and liquid,
fatty meats may develop
an odor, and it causes tissue softening in some fruits such as
peaches, nectarines, and
grapefruits. Foods that are currently approved for irradiation in
the United States include
fruits and vegetables; herbs and spices; fresh meat, pork, and
poultry; wheat flour; and
white potatoes.68
Although irradiation has many advantages, it doesn’t guarantee
that a food is free
from all pathogens, and some foods such as steak tartare (a dish
that contains raw ground
modified atmosphere packaging
(MAP) Food preservation technique that
changes the composition of the air surrounding
the food in a package to extend its shelf-life.

high-pressure processing (HPP) Method
used to pasteurize foods by exposing the items
to pulses of high pressure, which destroys the
microorganisms that are present.
irradiation Process in which foods are placed
in a shielded chamber, called an irradiator,
and subjected to a radiant energy source; kills
specific pathogens in food by breaking up the
cells’ DNA.
▲ Figure 20.8 FDA-Approved Uses of Irradiation
The international radura symbol must appear on all irradiated
foods.
Approved foods
Controls insects
Fruits and vegetables
Delays maturation
Spices and dry
vegetable seasonings
Decontaminates and
controls insects and
microorganisms
Meats
(beef, lamb, pork)
Controls spoilage and
disease-causing

microorganisms
Poultry
Controls disease-causing
microorganisms
Dry or dehydrated
enzyme preparations
Controls insects and
microorganisms
beef) should still not be eaten raw, even if they have been
irradiated. Irradiation comple-
ments but does not replace the need for proper food-handling
practices by food growers,
processors, and consumers.
Product Dating Identifies Peak Quality
Expiration dates on almost all food products, with the exception
of certain poultry, baby
food products, and infant formulas, are provided voluntarily by
food manufacturers and
are not required by federal law. However, currently more than
20 states require some form
of mandatory food product dating.
There are two types of food product dating: closed dating and
open dating. Closed
(or coded) dating refers to the packing numbers used by
manufacturers that are often
found on nonperishable, shelf-stable foods, such as cans of soup
and fruit (Figure 20.9a).
The manufacturer uses this type of dating to keep track of date
and time of production,
product inventory, and the location of products in the event of a
recall.69

Open dating is more useful for the consumer and is typically
found on perishable
items such as meat, poultry, eggs, and dairy foods. Open dating
must include at least a
month and a day, and if the product is shelf-stable or frozen, the
year must also be included
(see Figure 20.9b). Open dating can help consumers determine
if a product is at its peak
quality but not if it is safe to eat. For example, a carton of
yogurt that has been mishandled
and not refrigerated for several hours may be unsafe to eat even
though the date on the
container hasn’t passed.
Open-dated products must also contain a phrase next to the date
that tells the con-
sumer how to interpret it. If there is “Sell By” next to the date,
the product should be
purchased on or before that date. This date takes into
consideration additional time for
storage and use at home, so if the food is bought by the “Sell
By” date it can still be eaten
at a later date. If there is “Best if Used By” or “Use By” next to
it, the date shows how
long the manufacturer thinks a food will be of optimal quality.
This does not necessarily
mean that the product should not be used after the suggested
date, as these dates refer to
product quality, not safety.70
The Safety of the Water Supply Is Regulated
The Environmental Protection Agency (EPA) is the government
body responsible for
ensuring that consumers have a safe water supply; the Safe
Drinking Water Act (SDWA)

is the principal federal statute that affords that protection.
Health-based standards are
closed or “coded” dating Refers to the
packing numbers that are decodable only
by manufacturers and are often found on
nonperishable, shelf-stable foods.
open dating Typically found on perishable
items such as meat, poultry, eggs, and dairy
foods; must contain a calendar date.
▲ Figure 20.9 Closed and Open Food
Product Dating
Closed food product dating refers to
the coded packing numbers that you
often see on nonperishable foods such as
canned soups.
a
Open food product dating must
contain a calendar date and is used on
perishable food items along with
information on how to use the date.
b
Sustainability
preservatives Substances that extend the
shelf-life of a product by retarding chemical,

physical, or microbiological changes.
set by the EPA to protect the drinking water in the United States
from unsafe levels of
contaminants. In most cases the EPA delegates to the states
responsibility for ensuring
that the health standards are met. The EPA collects and stores
annual reports of each
state’s drinking water in a database called the Safe Drinking
Water Information System
(SDWIS). If there is an immediate threat to consumer health due
to violation of a drinking
water standard, the SDWA requires that public water systems
notify consumers through
the media or mail.71
Lead is a naturally occurring element found in the soil, air, and
water around our
homes. Lead exposure from paint and pipes made with lead can
be harmful. In children,
even low levels of lead in the blood can impair cognitive
development. Pregnant women
exposed to lead are at risk of premature birth and reduced
growth of the fetus, while other
adults can experience cardiovascular and kidney dysfunction.72
Whereas a small amount of lead in public water is normal, the
EPA declared a federal
state of emergency when Flint, Michigan, residents were
exposed to water containing high
levels of lead. The exposure occurred when the city switched to
the Flint River as its source
for public drinking water. This water’s high acidity caused lead
in the outdated municipal
pipes to leach into the water. Residents were warned to use
bottled water for drinking and

bathing until the pipes could be replaced in 2020. The city’s
slow response to the crisis
contributed to the residents’ contamination and became the
subject of national news.
LO 20.3: THE TAKE-HOME MESSAGE Several government
agencies, including
the FDA and USDA, share responsibility for food safety in the
United States.
HACCP is a food safety program used by the FDA, the USDA,
and the food
industry to identify and control hazards that may occur in any
part of the food
system. Manufacturers may use techniques such as
pasteurization, can-
ning, and irradiation to preserve food and destroy contaminants.
The FDA has
approved the use of irradiation in the U.S. food supply even
though some con-
sumers have concerns about the safety of irradiated foods. Most
food product
dating is provided voluntarily and can help determine peak
quality but not food
safety. The EPA is responsible for ensuring the safety of our
water supply.
What Role Do Food Additives
and Other Chemicals Play
in Food Production and Safety?
LO 20.4 Compare the risks and benefits of food additives and
the use of hor-
mones, antibiotics, and pesticides in both traditionally and
organically grown
food.

Food manufacturers use various types of food additives for
many different reasons.
Commonly used additives include preservatives (such as
antioxidants and sulfites), nutri-
ents, and flavor enhancers (such as MSG). Food producers also
give food-producing
animals hormones and antibiotics to improve the health and
food yield of these animals,
but they may cause unintentional side effects in consumers.73
Other food producers use
pesticides on plants to protect them and boost production.
Some Additives Are Used to Preserve Foods
Most food additives are preservatives that are added to foods to
prevent spoilage (usually
by destroying microbes) and increase shelf-life. The most
common antimicrobial preserva-
tives are salt and sugar. Salt has been used for centuries,
particularly in meat and fish, to
food additives Substances added to food
that affect its quality, flavor, freshness, and/or
safety.
What Role Do Food Additives and Other Chemicals Play
in Food Production and Safety? 753
create a dry environment in which bacteria cannot multiply.
Most (65 percent) of the salt
consumed in the United States comes from processed and
prepared foods that you find in
grocery and convenience stores.74 Sugar is used for the same
preserving effect in products
such as canned and frozen fruits and condiments.

Nitrites and nitrates are ionic salts, chemical compounds that
result from the bond-
ing of a positively charged ion to a negatively charged ion, that
are added to foods to
prevent microbial growth. They are used in cured meats such as
hot dogs and hams to
prevent the growth of Clostridium botulinum. These chemicals
give processed meats their
pink color. The use of these salts has been controversial because
they form carcinogenic
nitrosamines in the GI tract of animals.75
The addition of antioxidants to foods can prevent an off taste or
off color in a product
that’s vulnerable to damage by oxidation. Currently the
antioxidant vitamins E and C are
approved for use as food additives. Fat-soluble vitamin E is
often added to oils and cereals
to prevent rancidity. Water-soluble vitamin C is often added to
cut fruit to prevent pre-
mature browning. Butylated hydroxyanisole (BHA) and
butylated hydroxytoluene (BHT)
are chemical antioxidants that are also used as preservatives.
Although some studies into
BHT and BHA have linked high amounts to cancer, the current
body of research evidence
suggests that their use in foods is safe.76
Sulfites are a group of antioxidants that are used as
preservatives to help prevent the
oxidation and browning of some foods and to inhibit the growth
of microbes.77 Sulfites
are often found in dried fruits and vegetables, packaged and
prepared potatoes, wine, beer,
bottled lemon and lime juice, and pickled foods. For most

people sulfites pose no risk, but
sulfur dioxide causes adverse reactions in some people.78 The
FDA has prohibited the use of
sulfites on fruits and vegetables that are served raw, and foods
containing sulfite additives or
ingredients treated with sulfites must declare “added sulfites” in
the ingredients list on the
label. Food sold in bulk, such as dried fruit treated with sulfites,
must display the ingredients
on a sign near the food. Because sulfites destroy the B vitamin
thiamin, the FDA prohibits
their use in enriched grain products and other foods that are
good sources of this vitamin.79
Some Additives Enhance Food Quality and Appeal
Food manufacturers also use additives to increase the quality or
appeal of their prod-
ucts. Some additives improve food texture and consistency.
Others enhance the nutrient
content, color, or flavor of food. Table 20.5 lists some
commonly used nonpreservative
additives and their functions in foods.
nitrites and nitrates Substances that can be
added to foods to function as a preservative
and to give meats such as hot dogs and
luncheon meats a pink color.
sulfites Preservatives used to help prevent
foods from turning brown and to inhibit the
growth of microbes; often used in wine and
dried fruit products.
Dried fruits often have sulfur dioxide or other
sulfites added to them to preserve color and
flavor. People with sulfite sensitivity should

avoid products containing these additives.
Additive(s) Function(s) Found in
Alginates, carrageenan, glyceride, guar gum,
lecithin, mono- and diglycerides, methyl cellulose,
pectin, sodium aluminosilicate
Impart/maintain desired
consistency
Baked goods, cake mixes, coconut, ice cream,
processed cheese, salad dressings, table salt
Ascorbic acid (vitamin C), calcium carbonate, folic
acid, thiamine (B1), iron, niacin, pyridoxine (B6),
riboflavin (B2), vitamins A and D, zinc oxide
Improve/maintain nutritive value Biscuits, bread, breakfast
cereals, desserts,
flour, gelatin, iodized margarine, milk, pasta,
salt
Ascorbic acid, benzoates, butylated hydroxyani-
sole (BHA), butylated hydroxytoluene (BHT), citric
acid, propionic acid and its salts, sodium nitrite
Maintain palatability and
wholesomeness
Bread, cake mixes, cheese, crackers, frozen
and dried fruit, lard, margarine, meat, potato
chips
Citric acid, fumaric acid, lactic acid, phosphoric
acid, sodium bicarbonate, tartrates, yeast

Produce light texture and control
acidity/alkalinity
Butter, cakes, cookies, chocolates, crackers,
quick breads, soft drinks
Annatto, aspartame, caramel, cloves, FD&C Red
No. 40, FD&C Blue No. 1, fructose, ginger, limo-
nene, MSG, saccharin, turmeric
Enhance flavor or provide desired
color
Baked goods, cheeses, confections, gum,
spice cake, gingerbread, jams, soft drinks,
soup, yogurt
Source: Adapted from FDA. 2014. Food Additives Status List.
Available at
https://www.fda.gov/food/ingredientspackaginglabeling/foodadd
itivesingredients/ucm091048.htm.
Accessed April 2017.
TABLE 20.5 Commonly Used Food Additives
Sustainability
Additives to Enhance Texture and Consistency
Food additives can enhance the texture and consistency of food
in a number of ways.
Gums and pectins are often added to thicken yogurts and
puddings. Emulsifiers improve

the stability, consistency, and homogeneity of high-fat products
like mayonnaise and ice
cream. Lecithin is an example of an emulsifier that is often
added to salad dressings.
Leavening agents such as yeast or baking powder cause dough
to rise before it’s baked.
Anticaking agents such as sodium aluminosilicate and calcium
carbonate prevent products
like powdered sugar that are crystalline in nature from
absorbing moisture and lumping.
Humectants such as propylene glycol increase moisture in
products so that they stay fresh.
Additives to Improve Nutrient Content
Additives can be used to enhance a product’s nutritional
content, such as when refined
grains are enriched and fortified with added B vitamins (folic
acid, thiamin, niacin, and
riboflavin) and iron. In some cases, the federal government
mandates such additions. This
was the case in 1996, when the FDA published regulations
requiring the addition of folic
acid to enriched breads, cereal, and other grain products in
order to help decrease the risk
of neural tube defects in newborns.
Additives to Improve Color
Additives can also enhance the color of foods. There are two
main categories that make
up the FDA’s list of permitted colors. “Certifiable” color
additives are man-made and are
derived primarily from petroleum and coal. You can recognize
these types of additives
by the following prefixes: FD&C, D&C, or Ext. An example is
FD&C Yellow, which is
often found in cereals and baked goods. The second main

category of color additives is
obtained largely from plants, animals, or minerals. Examples
include caramel and grape
color extract.
Adverse physical or allergic reactions to color additives are
rare, although FD&C
Yellow No. 5 may cause itching and hives in some people. This
additive is found in bever-
ages, desserts, and processed vegetables and must be listed as
an ingredient on food labels.
MSG to Enhance Flavor
Monosodium glutamate (MSG) is the sodium salt of glutamic
acid, a nonessential
amino acid, and is often used as a flavor enhancer in Asian
foods, canned vegetables and
soups, and processed meats. Consumers can buy it in a form that
is similar in texture to
salt. Although it doesn’t have a strong taste of its own, it
enhances sweet, salty, sour, and
bitter tastes.
After an extensive review, the FDA confirmed that MSG is safe
to consume in the
amounts typically used in processed foods and cooking (a
typical meal that contains MSG
has less than 0.5 gram). However, when consumed in large
quantities such as 3 or more
grams at a time, it may cause short-term reactions in people
who are sensitive to it.80 These
reactions, which are called the MSG symptom complex, can
include numbness, a burn-
ing sensation, facial pressure or tightness, chest pain, rapid
heartbeat, and drowsiness. In
addition, people with asthma may have difficulty breathing after

consuming MSG. For
these reasons, the FDA requires that all foods containing MSG
declare this ingredient
on the food label.
Food Additives Are Regulated by the FDA
Food additives are strictly regulated by the FDA, with consumer
safety a top priority.
The Federal Food, Drug, and Cosmetic Act of 1938 gave the
FDA authority to regulate
food and food ingredients, including the use of food additives.
The 1958 Food Additives
Amendment further mandated that manufacturers document a
food additive’s safety and
obtain FDA approval before using it in a food.81
monosodium glutamate (MSG) Sodium salt
of glutamic acid, used as a flavor enhancer.
What Role Do Food Additives and Other Chemicals Play
in Food Production and Safety? 755
Two categories of food additives were exempted from this
amendment. The first
category includes substances that were known to be safe before
1958 and were given
prior-sanctioned status.82 For example, because nitrates were
used to preserve meats
before 1958, they have prior-sanctioned status, but only for
their use in meats. They can’t
be used in other foods, such as vegetables, without FDA
approval. The second category
includes substances that have a long history of being safe for
consumption, such as salt,

sugar, and spices, or have extensive research documenting that
they are safe to consume,
such as vitamins and MSG. These additives are categorized as
generally recognized as
safe (GRAS) and are exempt from FDA approval.83
The FDA continually monitors both prior-sanctioned additives
and those with
GRAS status to ensure that current research continues to
support their safety. To remain
on the GRAS list, an additive must not have been found to be
carcinogenic in animals or
humans and must be safe for human consumption. The 1958
Food Additives Amendment
also included the DeLaney Clause, which states that no
substances that have been shown
to cause cancer in animals or humans at any dosage may be
added to foods. However, with
the present increases in technology and the ability to detect
substances at very low levels,
the clause is considered outdated. To address this issue the FDA
deems additives safe if
lifetime use presents no more than a one-in-a-million risk of
cancer in human beings. If
an additive is suddenly called into question, the FDA can
prohibit its use or require that
the food manufacturer conduct additional studies to ensure its
safety.
The food additives discussed in the preceding sections are all
intentional food addi-
tives used to improve the quality of food products. However,
the FDA also regulates
unintentional food additives, very small amounts of substances
that enter foods during
packaging or processing. For example, dioxins used during the

manufacture of bleached
paper such as coffee filters may end up in coffee and other
foods and beverages. Dioxins
can accumulate in the food chain and are carcinogenic to
animals. The FDA requires that
dioxin levels in products be so low as to present no health risks
to people.84
Hormones and Antibiotics Are Provided to Food-Producing
Animals
Hormones and antibiotics are two classes of compounds that are
sometimes used to
improve the health or output of food-producing animals. While
the use of these sub-
stances is intentional, the resulting changes in the final food
product are not, and these
changes are a subject of controversy and consumer concern.
Bovine Growth Hormone
Cows naturally produce bovine growth hormone (BGH), also
known as bovine somatotropin. Some dairy farmers and
ranchers
treat their cattle with the naturally occurring form of BGH in
order
to produce animals that are leaner and produce more milk.
Scien-
tists can also produce a synthetic version of the hormone,
recom-
binant bovine somatotropin (rBST), and cows injected with
this form can produce up to 25 percent more milk than untreated
cows.85
Consumer groups and Health Canada (the FDA equivalent in
Canada) have questioned the long-term safety of rBST. Traces
of
both the synthetic and natural form of BGH remain in the meat

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