in the emergence of food-related illness. Irresponsible actions by individuals both before and after harvest of the food (improper storage, poor home sanitary practices, improper cooking techniques) undermine the effort to control microbial proliferation through responsible regulatory compliance, surveillance, and quality assurance. However, sterile packaging and irradiation could substantively alter (eliminate) the capability for even drug-resistant organisms to proliferate in foods prior to cooking and decrease the assessed risk to humans.
Increased international trade, reduced barriers to transport, increased efficiency in processing and delivery, and higher consumption approach or, in some cases, exceed the capacity of current surveillance mechanisms. It is virtually impossible to prevent infectious agents in food from reaching consumers, and efforts toward this end need to be strengthened.
The federally established standards and allowable tolerance levels for many drugs and residues are not zero, and detection of residues should not be equated with adulteration. No assurances can prevent ignorant action, accidents, or breaching of ethical standards in the use of animals that result in animal-derived foods, being adulterated with drug residues. Sophisticated methods for monitoring residues can be used to remove tainted products from the food chain, but every carcass cannot be monitored.
Bacteria are a natural part of the body’s internal and external ecology and environment. Some bacteria are beneficial, most are benign, and their presence is kept in balance through the functions of the immune system, naturally produced antibacterial peptides in skin and epithelial tissues, and microbial populations normally competing with “foreign” bacteria within a stable internal environment. Bacterial infections in any animal, including humans, fall into two categories: subclinical and occult; clinical and overt. Animals and humans can have low levels of pathogens that do not cause detectable disease or illness. A stable internal environment is critical for maintaining health. If environmental, nutritional, or behavioral stresses impinge on an animal or human population, the imbalance in the internal environment (altered adrenal and glucocorticoid hormone concentrations, altered cytokine concentrations, metabolic acidosis, and ruminal disturbances) can trigger the proliferation of bacterial populations that become harmful by spreading infection or release of endotoxins and exotoxins.
Antibiotics are used to treat infections, but maintaining the animal’s internal environment (the gastrointestinal tract and absorptive processes) is another use in animal production. This involves giving antibiotics for longer periods of time and at concentrations lower than those administered for therapeutic treatment (Fagerberg and Quarles 1979).
Antibiotics can be applied in three ways. In one, a single antibiotic is administered at subtherapeutic concentrations for an extended period to maintain the