Food Microbiology

Pasteurization of milk and milk products is so common today that it is hard to fathom that only during the twentieth century have federal, state, and local laws mandated it for all milk products. Although most large cities have required milk to be pasteurized since 1900, as late as 1930 most milk sold in rural areas was not routinely pasteurized. As a result, human diseases such as brucellosis and tuberculosis were fairly common.

Alice Catherine Evans, the first woman president of the Society ofAmerican Bacteriology (now the American Society for Microbiology), helped establish the connection between unpas-teurized milk and brucellosis in humans. A graduate of both Cornell University and the University ofWisconsin, Evans worked for the U.S. Department of Agriculture, seeking out the sources of microbial contamination of dairy products. In 1917, Evans reported that cases ofhuman brucellosis were related to the finding ofBrucella abortus in cows' milk. Her conclusion that B. abortus could be transmitted from cows to humans through milk conflicted with the prevailing view of a number of prominent scientists, including Robert Koch. In 1900, Koch had declared that bovine tuberculosis and brucellosis could not be transmitted to humans. As a result, at least 30 years elapsed before many scientists and dairy workers would accept the increasing evidence that diseases could be transmitted from cows to humans through the milk supply.

In the 1920s, dairy herds were inspected and vaccinated for tuberculosis. Herds that passed inspection and were vaccinated were called certified herds, and their milk could be sold commercially without pasteurization. In the late 1930s, after a number of the children of dairy workers had died of brucellosis even though they had drunk only certified milk, the problem of milk-borne disease was finally acknowledged. Today, milk is routinely pasteurized, and only very small amounts of unpasteurized milk are sold in the United States.

—A Glimpse of History

WHEN YOU PREPARE A MEAL, YOU ALSO INVITE A host of microorganisms to dinner. Practically all the food we purchase or grow, be it fruit, vegetable, meat, or dairy product, harbors a variety of microorganisms. This is not surprising when one considers that bacteria and fungi are ubiquitous and are especially plentiful in soil and around animals. From the micro-bial perspective, food can be viewed as a fertile ecosystem in which these organisms vie for the nutrients. The successful microorganisms are able to multiply and predominate.

Was this article helpful?

0 0
You Are What You Eat

You Are What You Eat

Nutrition is a matter that people spend their careers learning about and requires volumes of books to explain. My objective is to instruct you how to consume a healthy nutritional diet that aids your body in burning off fat instead of storing it. You do not require overwhelming science to get this.

Get My Free Ebook

Post a comment