2. Learning Objectives
• Identify and give examples of each of the
three main types of foodborne hazards
• Discuss how infections, intoxications, and
toxin-mediated infections cause foodborne
illness.
• List the factors that promote bacterial
growth
• Identify the Temperature Danger Zone
3. Learning Objectives
• Explain how temperatures in the danger
zone affect bacterial growth
• Identify the major types of potentially
hazardous foods and the characteristics
that are common to this group of foods.
7. Foodborne Infection
• Happens when a
disease causing
organism is eaten
along with the food
• After ingestion, the
organism burrows into
the lining of the
victim’s digestive tract
and begins to grow in
number.
8. Intoxication
• Happens when a living
organism multiplies in or on
a food and produces a
chemical waste or toxin.
• Also, when an individual
consumes food that contains
man-made chemicals such
as cleaning agents or
pesticides.
9. Toxin-mediated Infection
• Happens when a living
organism is consumed
with food. Once inside
the human body, it
produces a toxin that
causes the illness.
10. Onset Time
• The number of hours
between the time the
person eats a
contaminated food and
when they first show
signs of the disease.
• Foodborne illnesses
have different onset
times.
11. Onset Time
• The onset time varies depending on
factors such as: age, health status, body
weight, and the amount of contaminant
ingested with the food.
12. High Risk Population
• These individuals’ symptoms and duration
of foodborne illness can be much more
severe and even life threatening.
13. Foodborne Hazards
• Refers to Biological, Chemical or
Physical Hazards that can cause illness
or injury when consumed along with the
food.
14. Biological Hazards
• Include bacteria, viruses, parasites and
fungi.
• These organisms are very small and can
only be seen with the aid of a microscope.
15. Biological Hazards
• Many of these organisms occur naturally
in the environment where the foods grow.
• Most are destroyed by adequate cooking,
and numbers are kept to a minimum by
proper cooling during distribution or
storage.
16. Chemical Hazards
• Are toxic substances that may occur
naturally or be added during the
processing of the food.
17. Physical Hazards
• Are hard or soft foreign objects in food that
can cause illness or injury.
19. Bacteria
• The most important biological foodborne
hazards for any food establishment.
• Bacteria are reported in more cases of
foodborne illness than any other hazard.
20. Bacteria
• Vegetative State – cells grow, reproduce
and produce wastes
• Spore State – some bacteria have the
ability to form spores. Spores help
bacteria survive when their environment is
too hot, cold, dry, acidic or when there is
not enough food.
23. Bacteria
• Spoilage Bacteria – degrade or break
down food so that they look, taste and
smell bad.
• Pathogenic Bacteria – are disease
causing microorganisms that can make
people ill if they or their toxins are
consumed with food.
24. Bacterial Growth
• Bacteria reproduce
when one bacterial
cell divides to form
two new cells. This
is called Binary
Fission.
26. Four Phases
• Lag Phase
• Log Phase
• Stationary Phase
• Decline Phase
27. Lag Phase
• Phase in which bacteria exhibit little or no
growth.
• Lasts only a few hours at room
temperature.
28. Log Phase
• Logarithmic or Exponential Growth
• Bacterial growth is very rapid during the
log phase with bacteria doubling in
numbers every few minutes.
29. Stationary Phase
• The number of new bacteria being
produced equals the number of organisms
that are dying off during this phase.
30. Decline Phase
• Bacteria die off rapidly because they lack
nutrients and are poisoned by their own
toxic wastes.
32. Source of Food
• Most bacteria prefer foods that are high in
protein or carbohydrates like meats,
poultry, seafood, dairy products, and
cooked rice, beans, and potatoes.
33. Acidity
• The symbol pH is used to designate the
acidity or alkalinity of a food. (range 0-14)
• Acidic foods have pH of less than 7.0
• Foods with pH above 7.0 is alkaline
• Bacteria grow best in foods that have 4.6-
7.0 pH
38. Temperature Abuse
• Is the term applied to foods that have not
been heated to a safe temperature or not
kept at proper temperature.
39. Time
• The rule of thumb in the foodservice
industry is that bacteria need about
4hours to grow to high enough numbers to
cause illness.
40. Oxygen
• Aerobic bacteria – must have oxygen to
grow
• Anaerobic bacteria – cannot survive
when oxygen is present
• Facultative Anaerobic bacteria – can
grow with or without oxygen
• Microaerophilic organisms – specific
oxygen requirements usually 3%-6%
41. Moisture
• Water Activity (Aw) a measure of the
amount of water that is bound to the food
and is, therefore available for bacterial
growth.
