Salts and edible oils are the common chemicals generally used to check the growth of microorganisms. Thereforethey are called preservatives. We add salt or acid preservatives to pickles to prevent the attack of microbes. Sodiumbenzoate and sodium meta bisulphite are common preservatives. These are also used in jams and squashes to checktheir spoilage.
The milk is heated to about 70 degree C for 15 to 30 seconds and then suddenly chilled and stored. By doing so, it prevents the growth of microbes. This process was discovered by Louis Pasteur. It is called pasteurisation.
Robert Köch (1876) discovered the bacterium (Bacillus anthracis) which causes anthrax disease
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. …
Pathogen are transmitted by direct contact with an infected person or carried by an animal.Microbial diseases that can spread from an infected person to a healthy person through air, water, food or physicalcontact are called communicable diseases. Examples of such diseases cholera, common cold, chicken pox and tuberculosis.
Disease-causing micro – organisms are called Pathogens.The Nitrogen fixing cyanobacteria (blue green algae)
Some bacteria are able to fix nitrogen from the atmosphere to enrich soil with nitrogen and increase its fertility. These microbes are commonly called biological nitrogen fixers.
When a disease-carrying microbe enters our body, the body produces antibodies to fight the invader.
substance which is used to stimulate the production of antibodies, and provide immunity against one or a few diseases. vaccine works. Several diseases, including cholera, tuberculosis, smallpox and hepatitis can be prevented by vaccination.
. Edward Jenner discovered the vaccine for smallpox in 1798.
