Microbiological contamination and adulteration of food

The fact that a food is contaminated with pathogens (harmful microorganisms such as bacteria, viruses, or protozoa) may, or may not, render it adulterated. Generally, for ready-to-eat foods, the presence of pathogens will render the food adulterated. For example, the presence of Salmonella on fresh fruits or vegetables or in ready-to-eat meat or poultry products (such as luncheon meats) will render those products adulterated.

For meat and poultry products, which are regulated by USDA, the rules are more complicated. Ready-to-eat meat and poultry products contaminated with pathogens, such as Salmonella or Listeria monocytogenes, are adulterated. (Note that hotdogs are considered ready-to-eat products.) For raw meat or poultry products, the presence of pathogens will not always render a product adulterated (because raw meat and poultry products are intended to be cooked, and proper cooking should kill pathogens). Raw poultry contaminated with Salmonella is not adulterated. However, USDA's Food Safety and Inspection Service (FSIS) has ruled that raw meat or poultry products contaminated with E. coli O157:H7 are adulterated. This is because normal cooking methods may not reduce E. coli O157:H7 below infectious levels. E. coli O157:H7 is the only pathogen that is considered an adulterant when present in raw meat or poultry products.

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