MICROORGANISMS USES
BENEFICIAL MICROORGANISMS
They are used in:
1. The preparation of curd (Lactobacillus), bread and cake.
2. Some microorganisms decompose the organic waste and dead plants and animals into simple substances and clean up the environment.
3. The preparation of medicines- penicillin, antibiotics (Streptomycin, tetracycline and erythromycin ).
4. The manufacture of vaccines (substance which is used to stimulate the production of antibodies, thereby providing immunity against certain diseases.).
5. In agriculture they are used to increase soil fertility by fixing nitrogen (Cyanobacteria-blue green algae).
HARMFUL MICROORGANISMS
Some insects and animals which act as carriers of disease- causing microbes.
Ex: Housefly – carrier of harmful pathogens:
Anopheles mosquito -carries the parasite of malaria (Plasmodium).
Female Aedes mosquito – carrier of dengue virus.
1. DISEASE CAUSING MICROORGANISMS IN HUMANS
2. DISEASE CAUSING MICROORGANISMS IN PLANTS
3. DISEASE CAUSING MICROORGANISMS IN ANIMALS
1. Anthrax – caused by a bacterium.
2. Foot and mouth disease- caused by a virus.
FOOD POISONING
FOOD PRESERVATION
Chemical methods:
1. Chemical preservatives are used in food preservations by major food industries as they are harmless to humans.
2. Salts and edible oils -common chemicals generally used to check the growth of microorganisms.
3. Sodium meta-bisulphate and sodium benzoate are commonly used chemical preservatives.
Preservation by common salt:
1. Common salt (sodium chloride) is used as a preserve meat and fish, amla, raw mangoes, tamarind, etc.
Preservation by Sugar:
1. Sugar is used for the preservation of jams, jellies and squashes.
2. Sugar reduces the moisture content which inhibits the growth of bacteria which spoil food.
Preservation by oil and Vinegar:
1. Many food preparations like pickles are preserved by adding either oil or vinegar to them.
Bacteria cannot grow in such medium.
2. Vegetables, fruits, fish and meat can also be preserved.
Pasteurization:
1. Pasteurization is a process of superheating and cooling the beverages.
2. This prevents the growth of microbes.
Storage and Packing:
1. Dry fruits and many vegetables are preserved in airtight/air sealed containers.
2. The absence of air prevents the growth of bacteria or fungi.