PRACTICAL LABORATORY TESTS FOR FOOD MICROBIOLOGY

Microbiologic testing of foods is an increasingly important aspect of microbiology. Food microbiology focuses on two techniques-enumeration of bacteria as a measure of quality and detection of specific microorg anisms as a measure of foodborne disease hazard. Enumeration testing u sually is by means of direct culturing, using both nonselective and se lective media. Detection testing often involves the use of enrichment cultures to enhance the growth of microorganisms that are present in v ery small numbers or that have fastidious growth requirements. This pr ocess is followed by subculture and identification by biochemical test s, immunologic tests, or both. Viruses are more difficult to detect in food than are bacteria because viruses require living cells for propa gation and serologic, electron microscopic, or molecular biologic test s for identification. This is the final article in a four-part continu ing education series on microbiology. Other articles focused on public health laboratories, veterinary microbiology, and yeast involved in b read-making.