The document discusses various types of microorganisms, highlighting their beneficial roles in processes like decomposition, fermentation, and antibiotic production, as well as their harmful effects as pathogens causing diseases in humans, plants, and animals. It also addresses methods of disease prevention through vaccination and hygiene, and outlines various food preservation techniques such as drying, chemical preservatives, and heat treatments. Overall, the content emphasizes the dual nature of microorganisms as both allies and foes in our environment and health.

1. MICROORGANISMS
PPT BY NANDINI CHADHA
ROLL NUMBER 20
CLASS 8F
CHAPTER 2

2. Types of microorganisms
fungi protozoans algae
STAPHYLOCOCCUS
VIBRIO CHOLERAE
BREAD MOULD
YEAST
PARAMOECIUM
AMEOBA
Euglena
CHLORELLA
SPIROGYRA

3. MICROORGANISMS AS FRIENDS
Micro organisms play a very important role in our lives such as
They help in decomposition process,maintaining biogeochemical cycles
They help in curd and cheese formation.
They help in the process of fermentation
They are used in the manufacture of alcoholic beverages.
They are used in the biological treatment of sewage and industrial waste.
They are used in production of antibiotics.
They help in digestion of food in animals
They help in the agricultural processes.
They help in fuel production.
They help in cleaning the environment. Amount of micro-
organisms in our body

4. MICROORGANISMS AS FOES
• Some microorganisms are harmful in many different ways.The disease causing
micro organisms are known as PATHOGENS.Some of these leave undesirable
effects on our body.These release some harmful materials called TOXINS.
Harmful microorganisms can cause diseases in plants,animals and humans as
well.
MICROORGANISM DISEASE
BACTERIA Tuberculosis,Diphtheria,Cholera,Tetanus,Typhoid
VIRUSES Common cold,Influenza,Mumps,Polio,Chickenpox,Aids
FUNGI Ringworm,Athelete’s foot
PROTOZOANS Malaria,Amoebic dysentery,Sleeping sickness
DISEASE CAUSING MICROORGANISMS

5. MODES OF TRANSMISSIOM OF PATHOGENS
MODES OF TRANSMISSION DISEASES
AIR Tuberculosis,common cold,swine
flu,influenza
WATER Typhoid,amoebic dysentery,cholera
SOIL Tetanus
ANIMALS Rabies,malaria

6. PREVENTION OF DISEASES
METHODS OF VACCINATION DISEASES WHICH CAN BE
PREVENTED
VACCINATION TUBERCULOSIS,POLIO,PUMPS,MUMPS,
TETANUS
MOSQUITO NETS,REPELLENTS etc. MALARIA,DENGUE
PROPER DIPOSAL OF WASTE USING
DISINFECTED WATER
CHOLERA
MAINTAINING GOOD PERSONAL
HYGEINE
RINGWORM AND ATHELETE’S FOT

7. MICRO ORGANISMS CAUSING DISEASE IN
PLANTS AND ANIMALS

8. FOOD PRESERVATION
• FOOD PRESERVATION is the process of
treating or handling food so as to stop or
greatly slow down ,spoilage caused by
micro organisms
• PRESERVATION usually involves preventing
growth of bacteria ,fungi and other
microorganisms as well as retarding the
oxidation of fats which causes rancidity.

9. METHODS OF FOOD PRESERVATION
• DRYING -Drying basically dehydrates or removes the moisture
from the food and this simple action inhibits the growth of bacteria,
mold and yeast. ... These factors ensure that food does not spoil easily
and hence, makes drying an effective food preservation technique.
• USING SALT AND SUGAR- Salt and sugar also reduce the
water content and make it unavailable for the growth of
micro organisms…… as a result , food gets preserved.

10. MORE METHODS
• Preservation using chemical preservatives-CHEMICAL
PRESERVATIVES SUCH AS SODIUM BENZOATE AND POTASSIUM METABISULPHATE
ARE USED TO PRESERVE JAMS,JELLIES AND PICKLES.THESE INHIBIT THE
GROWTH OF MICRO ORGANISMS.
• Preservation using acetic acid-ACETIC ACID LIKE VINEGAR IS
USED IN THE MANUFACTURE OF SEVERAL PRODUCTS.VINEGAR STOPS THE
GROWTH OF MICRO ORGANISMS.CITRIC ACID AND PHOSPHORIC ACID ARE USED
IN CARBONATED BEVERAGES FOR BOTH FLAVOURING AND PRESERVATION.
• Heat and Cold treatments-SOME FOOD ITEMS ARE USUALLY BOILED
BEFORE THERE USE OR STORAGE.BOILING KILLS MICRO ORGANISMS
• .IN THE SAME WAY SOME FOODS ARE STORED IN REFRIGERATOR TO INHIBIT THE
GROWTH OF MICRO ORGANISMS.

11. PASTEURISATION- Heat-treatment process that
destroys pathogenic microorganisms in certain foods
and beverages.The treatment also destroys most of the
microorganisms that cause spoilage and so prolongs the
storage time of food. For example MILK.
CANNING- The canning process involves placing
foods in jars and heating them to a temperature that
destroys microorganisms that could be a health
hazard or cause the food to spoil. ... Air is driven from
the jar during heating, and as it cools, a vacuum seal
is formed.

12. VACCUM PACKING -Vacuum packing is a method
of packaging that removes air from the package prior to
sealing. This method involves (manually or
automatically) placing items in a plastic film package,
removing air from inside and sealing the package. ...
Vacuum packing greatly reduces the bulk of non-food
items.
FREEZING-To freeze foods rapidly, set
the temperature control at –10 degrees Fahrenheit or
lower 24 hours in advance. Keep a thermometer in
the freezer to assure proper freezing temperatures
are maintained. Freeze foods immediately after they
are packaged and sealed. Do not overload your
freezer with unfrozen food.