Microbiology in everyday life

Date:5/30/2021 www. qadricohs.edu.pk FB Page: Qadri College of Health Sciences, Karachi, Sindh, Pakistan. 1
QADRI COLLEGE OF HEALTH SCIENCES, KARACHI
U-5, 1 OF 1
“MICROBIOLOGY IN EVERYDAY LIFE”
By: Aftab H. Abbasi
RN, DCHN, BSN, MA, LL.B
Lecturer Nursing
Qadri College of Health Sciences Karachi

- In this unit learners will study about
how microorganisms affect our
environment i.e. air, water, food.

At the completion of this unit learners will be
able to:
1- Describe how microorganisms affects environment i.e. Air, Water
and Food.
2- List some Safety Measures to control water and food borne
diseases.
3- Differentiate between food infection and food poisoning.

What are airborne microorganisms?
Definition of Aero-microbiology:
“Study of living microbes suspended in air”
- Number of microorganisms in atmosphere but air is not a natural
environment for microorganisms because it does not contain enough
moisture and nutrient.
- Airborne microbes are biological airborne contaminants (also known as
bioaerosols), like bacteria, viruses or fungi as well as airborne toxins passed
from one victim to the next through the air, without physical contact.
- Bacteria are emitted from the human respiratory airways through talking,
coughing or sneezing. They also get into the air with skin scales.

How do infectious microorganisms contaminate drinking water?
- Of the many infectious microorganisms found in the
environment, bacteria (such as Shigella, Escherichia coli,
Vibrio, and Salmonella), viruses (such as Norwalk virus and
rotaviruses), and protozoans (such as Entamoeba, Giardia,
and Cryptosporidium) may be found in water.
- Infectious microorganisms may be present in human or
animal waste. Wells and other drinking water sources can be
contaminated by storm water run-off from roadways, farms
and livestock operations, discharges from sewage treatment
plants, or septic system discharges.

Common Diseases
Airborne:
- COVID-19
- The common cold
- Influenza
- Chickenpox
- Mumps
- Measles
- Whooping cough
(pertussis)
- Tuberculosis (TB)
Water-borne:
- Polio
- Malaria
- Cholera
- Dengue
- Scabies
- Typhoid
- Trachoma
- Hepatitis
- Diarrhea
- Hookworm infection
- Ring Worm or Tinea
Foodborne:
- Botulism
- E-coli infection
- Salmonellosis
- Shigellosis
- Listeriosis
- Staphylococcal Illnes
- Hepatitis-A
- Norwalk virus
- Rota virus
- Yeast
- Mold
- Giardiasis
- Cyclosporiasis
- Trichonosis

How Microorganisms Affects ?
- The primary harmful effects of microbes upon
our existence and civilization is that they are an
important cause of disease in animals and crop
plants, and they are agents of spoilage and
decomposition of our foods, textiles and dwellings
(place of residence).
- Microbes cause infectious diseases such as flu
and measles. There is also strong evidence
that microbes may contribute to many non–
infectious chronic diseases such as some forms of
cancer and coronary heart disease. Different
diseases are caused by different types of micro-
organisms.

- Several microorganisms not only cause diseases in humans
and plants, but also in other animals. For example, anthrax is
a dangerous human and cattle disease caused by a
bacterium. Foot and mouth disease of cattle is caused by a
virus.
- Robert Köch (1876) discovered the bacterium (Bacillus
Anthracis) which causes anthrax disease.

Several microbes cause diseases in plants
like wheat, rice, potato, sugarcane,
orange, apple and others. The diseases
reduce the yield of crops. They can be
controlled by the use of certain chemicals
which kill the microbes.

Microbes are harmful in many ways. Some of the microbes
cause diseases in human beings, plants and animals. Such
disease-causing microorganisms are called pathogens.
Pathogens enter our body through the air we breathe, the
water we drink or the food we eat. They can also get
transmitted by direct contact with an infected person or
carried through an animal. Microbial diseases that can
spread from an infected person to a healthy person through
air, water, food or physical contact are called
communicable diseases.
Examples of such diseases include cholera, common cold,
chicken pox and tuberculosis.
When a person suffering from common cold sneezes, fine
droplets of moisture carrying thousands of viruses are
spread in the air. The virus may enter the body of a healthy
person while breathing.

- There are some insects and animals
which act as carriers of disease-
causing microbes.
Housefly is one such carrier.
- The flies sit on the garbage and
animal excreta. Pathogens stick to
their bodies. When these flies sit on
uncovered food they may transfer the
pathogens.
- Whoever eats the contaminated food
is likely to get sick.
- Examples of carriers are: the female
Anopheles mosquito which carries the
parasite of malaria and Female Aedes
mosquito acts as carrier of dengue
virus.

Some Common Plant Diseases caused by Microbes

Some Common Human Diseases caused by Microbes

Food Spoilage
“Any sensory change (tactile, visual, olfactory or flavor)” which
the consumer considers to be unacceptable.
Spoilage may arise from insect damage, physical damage,
indigenous enzyme activity in the animal or plant tissue or by
microbial infections.
The main single cause of food spoilage is invasion by
microorganisms such as moulds, yeast and bacteria.
In case of mould spoilage a furry(a deposit or thick layer) growth covers the
food and it becomes soft and often smells bad.
The presence of highly dangerous toxins and bacterial spores
is often not detected until after an outbreak of food poisoning,
laboratory examination uncovers the infecting agent.

How do microorganisms spoil food?
Microbial spoilage is caused
by microorganisms like fungi
(moulds, yeasts) and bacteria.
They spoil food by growing in
it and producing substances
that change the color, texture
and odor of the food.
Eventually the food will be
unfit for human consumption.

Food poisoning is an illness caused by eating contaminated food.
The food is contaminated by bacteria, such as salmonella or
Escherichia coli (E. coli), or a virus, such as the norovirus.
Microbes that grow in our food sometimes produce toxic
substances. These make the food poisonous causing serious
illness and even death. So, it is very important that we preserve
food to prevent it from being spoilt.

Food borne Infection

Differentiate between food infection and food poisoning

Some Safety Measures
- Salts and edible(‫)خوردنی‬oils are the common chemicals generally used
to check the growth of microorganisms. Therefore they are called
preservatives.
- We add salt or acid preservatives to pickles to prevent the attack of
microbes.
- Sodium benzoate and sodium metabisulphite are common
preservatives. These are also used in jams and squashes to check
their spoilage.

- Common salt has been used to preserve meat and fish for ages. Meat and
fish are covered with dry salt to check the growth of bacteria. Salting is
also used to preserve amla, raw mangoes, etc.
- Jams, jellies and squashes are preserved by sugar. Sugar reduces the
moisture content which inhibits the growth of bacteria which spoil food.
- Use of oil and vinegar prevents spoilage of pickles because bacteria
cannot live in such an environment. Vegetables, fruits, fish and meat are
often preserved by this method.
- These days dry fruits and even vegetables are sold in sealed air tight
packets to prevent the attack of microbes.
- FREEZING This is the process by which food is solidified by bringing it to
temperatures between 0°F and 32°F, which in turn slows the metabolism
of foods and the spoilers that may live on them. Spoilers are not
destroyed, but they don’t bloom, either. With proper defrosting and prompt
cooking and/or heating, spoilers on foods that have been frozen will never
amount to anything. This process is effective for a large variety of foods.

Prevention of Food and Water Borne Illness
- Wash and/or peel all raw vegetables and fruits before eating.
- Drink and eat only pasteurized dairy products (milk, cheese, yogurt
and ice cream) and juices.
- Thoroughly cook all meats (meat, poultry and seafood). For
example, ground beef should be cooked to an internal temperature
of 71°C/160°F.
- Wash hands, kitchen work surfaces and utensils after contact with
raw meat or poultry.
- Wash hands before handling food and between handling different
food items.
- Prevent contact of cooked foods with raw foods (i.e., raw meat, and
poultry).
- Clean and sanitize all utensils, equipment and surfaces (cutting
boards, work counters, etc.) before and after each use.
- Be sure to use hot water and detergent to clean, then rinse with hot
water. Sanitize food contact surfaces with a sanitizing solution
- Avoid preparing food for others while you have symptoms and for 48
hours after you recover.

Drink properly treated water
- Do not drink untreated water from lakes,
rivers, springs, ponds, streams, or
shallow wells.
- Do not drink tap water or use ice while
travelling to a high-risk destination unless
the water source has been properly
treated.
- Drink only filtered/boiled water.
- Store water in a clean container.
- Water jars/containers should be washed
daily.

- Boiling kills many microbes in milk. Low
temperature inhibits the growth of
microbes.
- Pasteurized milk can be consumed without
boiling as it is free from harmful microbes.
The milk is heated to about 70 Degrees
Celsius for 15 to 30 seconds and then
suddenly chilled and stored.
- By doing so, it prevents the growth of
microbes. It is called pasteurization.

Methods to control Microbial Growth

By: Aftab H. Abbasi
RN, DCHN, BSN, MA, LL.B
Lecturer Nursing
Qadri College of Health Sciences Karachi

Microbiology in everyday life

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