Louis pasteur(1822_95)was a french chemist and micro biologist who made many significant contributions to the field of microbiology.He was considered to be the father of microbiology.

→He found that the microbes are involved in the process of fermentation.Further,he discovered that the fermentation is an anaerobic process.He passed air(oxygen)in the fermentation liquid and found that  the process of fermentation was arrested.This phenomenon is now popularly known as pasteur effect.

→He devised a sterilization technique to sterilize grape juice in the preparation of wine,which is now popularly known as pasteurization.

→He disproved the theory of spontaneous generation which states that living organism arise spontaneously by famous swan neck experiment.

→He had the opportunity to deal with silkworm infection in france.He proposed the idea of germ theory of disease which was not accepted by medical fraternity as he was a chemist.However,this led him to the path of medical microbiology.

→He developed the principle of preparation of vaccines.His accidental discovery of chicken cholera vaccine gave him the concept of preparation of vaccines.He understood the concept of attenuation wherein the pathogenic micro organism are made avirulent nut still can retain the capacity to elicit the immune response.Then,he studied on anthrax epidemic in france.At that time,Robert koch declared that the anthrax was caused by a bacillus.Pasteur confirmed the findings and soon the germ theory of disease was accepted.Thus,along with Robert koch,pasteur developed the vaccine for anthrax from the idea he got from chicken cholera and he demonstrated its validity before the people.Later,he prepared the first human vaccine for rabbies which marked the beginning of immunization.

Robert koch(1843-1910)was considered as the father of modern bacteriology.He got the Noble  prize in 1905.He studied the anthrax in detail.He isolated the bacterium and grew in mouse for many generations and confirmed that the anthrax is caused by a bacillus.This led to the germ theory of disease.His experimental design to prove the cause of anthrax is popularly stated as koch postulates which is as follows:

The micro organism should be found in all organism suffering from the disease.

The micro organism must be isolated from a diseased organism and grown in pure culture.

The cultured micro organism should cause the same disease when introduced into a healthy organism.

the mico organism must be re-isolated from the innoculated,diseased experimental host and identified as being identical to the original specific causative agent.

To prove that a particular organism is the causative agent of a disease,one should fulfil the koch postulate.Koch has contributed lot to the culture technique of bacteria.He introduced the use of agar to solidify the culture media.He also introduced staining technique to observe bacteria under microscope.Along with his colleague,petri,he designed a plate to prepare culture media,which is now popularly known as petri plate.Robert koch did extensive research in tuberculosis and discoverd the tubercle bacilli.

Thank you.