Food is a source of nutrients not only to humans but to microorganisms as well. The organic compounds and moisture that are often present in foods present an ideal environment for the growth of various microorganisms. The monitoring of the raw food and of any processing steps required prior to the consumption of the food are necessary to prevent transmission of disease-causing microorganisms from the food to humans.

Bacteria, viruses, parasites, and toxin by-products of microorganisms, chemicals, and heavy metals can cause foodborne maladies. These agents are responsible for over 200 different foodborne diseases. In the United States alone, foodborne diseases cause an estimated 75 million illnesses every year, and 7,000 to 9,000 deaths.

Aside from the human toll, the economic consequences of foodborne illnesses are considerable. In 1988, for example, human foodborne diarrheal disease in the United States cost the U.S. economy an estimated five to seven billion dollars...