Louis Pasteur (1822-1895) was a French Chemist and microbiologist. His classical discovery was that fermentation is caused by microorganisms. He also developed the germ theory of disease, and created a vaccine for rabies, which led to the foundation of the Pasteur Institue in Paris in 1888. Based on his hard work and perseverance he discovered the pathogens for anthrax and cholera, and later developed vaccines for these diseases. He inspired his worthy pupil Joseph Lister to develop antiseptic surgery. He was also responsible for working out details of pasteurization to make dairy products free from harmful bacteria.
Once Pasteur was consulted by a brewer who wanted him to find out the defect in his bear, which had caused the brewer heavy losses. Pasteur set out to work and examined the yeast under the microscope, and found two kinds of yeast, one round and the other long. The round yeast came from good bear, and the long yeast from the bad bear. He also showed that there is nothing like Spontaneous Generation,and life cannot arise by itself. Thus he established the wine making industry in France.
Now it is well known that where beer and wine are made, alcohol is generated; where vinegar is made, acetic acid is produced; and where milk sours, lactic acid is produced. This process is happening by fermentation. Thus Pasteur modified the whole basis of medicine, surgery, physiology, and biology, and placed bacteriology on a sound foundation.
Pasteurization of food to reduce the number of microorganisms is done to protect consumers from diseases. Harmful bacteria are killed and the development of others is checked and delayed. For pasteurization of milk the method involves heating it to 72 degrees C for 15 seconds, followed by rapid cooling to 10 degrees C or lower. This process kills bacteria responsible for tuberculosis, typhoid, diphtheria, and dysentery.
It is noteworthy that great advances in the history of medicine were made by Pasteur who was not a medical doctor. In 1822 in Central France, wife of a tanner bore a son named Louis, who later became a great benefactor of the human race. When Louis was sixteen he was sent to Paris to study Latin. But he did not like the hustle and bustle of Paris. Soon he returned home, and was sent to the Royal College of Besaneon, and took the degree of Bachelor of Literature, followed by taking the same degree in Science. Later he proved that tartaric acid existed in two distinct forms. One deviated the polarized light to the left and the other to the right. After this discovery Pasteur was offered the post of Professor of Chemistry at Strasbourgh. Here he preached that "Chance favors only those who are prepared".
Next Pasteur turned his attention to the possibility of protection against disease and immunity against them. He developed the technique of "culturing" microorganisms. This led to the crowning discovery of "toxins" and 'antitoxins", and the preparation made from animals was called "serum". Thus the concept of "immunity" was established. With this concept Pasteur came up with cures for "chicken cholera" and "anthrax". The next discovery was treatment for the horrible disease "hydrophobia" (rabies). It was based on the study on dogs, as they were the chief carriers of the rabies.
Unspoilt by the honors showered on Louis Pasteur he truly was a great worker and benefactor of mankind. He left this world at the age of
seventy-three on September 25th 1895.
Ref: "Ferments and Germs"; In Quest and Conquest by Malcolm Burr, Oxford University Press, Bombay 1946.