Pasteur

There is perhaps no other individual whose influence is experienced worldwide every day. When one considers that milk and wine can be used and stored for days without fear of spoilage, the word pasteurization comes to mind. This is the process of removing bacteria from the beverage (one way would be by heating and rapid cooling) such that it prevents fermentation. This process was identified and perfected for daily use by one Louis Pasteur. In the pantheon of the 100 most influential people ever, this French chemist and microbiologist stands 11th. (Hart, 1992)

Louis Pasteur was born in Dole in France on December 27, 1822. His school work was not spectacular but he showed an (abbreviated) interest in art (and was a promising artist) and chemistry. Though Pasteur is famous for a slew of inventions and discoveries (described later in this essay) that health specialists take for granted today, few know that he started his scientific career as a chemist. If the biography of Pasteur's life examined in briefly, his achievements seem eclectic. But there is a logical progression of scientific work that allowed him to make the assumptions and connections that are only obvious to the truly great and yet seem obvious in hindsight to the rest of us. This essay will highlight Pasteur's accomplishments and his contribution to chemistry, biochemistry and health sciences through these connections. (Debre & Forster, 1998)

Few know that Pasteur's scientific career began as a crystallographer. This science purports to distill every element and compound to its three dimensional shape and arrangement in its solid form. While studying tartarate crystals that can be found in the sediments of wine, Pasteur discovered that similar looking and behaving crystals were essentially different: they rotated plane polarized light in different directions. Naturally created products were more specific in their behavior than the same product manufactured in laboratories. This gave rise to the notion of stereochemistry and chirality (a carbon atom in an organic molecule that is attached to different atoms and groups). (Morris & Abel, 2002) Here is an example of how chirality is critical. D-Glucose containing certain chiral carbon atoms is responsible for metabolic activities in the body. Artificially manufactured L-Glucose though physically similar if introduced in the body, not only does not perform the function of its D-alternate, but has a debilitating effect on the body.

Pasteur discovered that the tartarate in wine that was contaminated with mould showed different chirality. He deduced that some factor in wine induced chemical changes in it. He showed first that yeast was responsible for fermentation of sugar into alcohol and that this yeast resided in the skin of grapes. He did this by showing that grape juice extracted from under the skin under sterile conditions did not produce wine neither did grapes whose skin had been protected from outside influences. He realized that certain bacteria were responsible for the spoilage of wine (creating of acetic acid vinegar) or the spoilage of vinegar through the creation of lactic acid. Similar effects were observed in milk. By heating the wine and the milk, thereby killing the harmful bacteria, Pasteur could ensure the quality of almost all beverages.

Pasteur showed that fermentation and spoilage was due to outside influences. This helped support the notion of germ theory that had been advanced by other scientists. Germ theory postulated that bacteria and other harmful influences resulted in the disease. Pasteur showed that only broths that were exposed to air could result in fermentation and spoilage. The process of Pasteurization proved this.

This had consequences that went beyond health. Pasteurs work was one of the earliest that supported evolution and dispel the ideas…