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Detection of Unwholesome Meat


Charles M. Scanlan

, DVM, PhD, Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University

Last full review/revision Sep 2013 | Content last modified Jun 2016

Meat for human consumption should be prepared from animals that were healthy and have been exsanguinated. Animals having physical, infectious, or toxic agents that may be hazardous to human health or that are otherwise unwholesome in their tissues should not be used for food. Fitness for food can be determined by a comprehensive evaluation that may include chemical, histologic, microbiologic, organoleptic, and toxicologic examinations.

Meat should be examined under light of adequate intensity. Foreign objects on the surface or visible within the tissue should be collected for further examination. Items such as feathers, fibers, hair, insect larvae, or parasites may provide valuable data on the species, origin, and handling of the meat. Color, odor, and texture should be noted. Meat should be firm, and cut surfaces should be glossy. Gray or green discoloration may indicate bacterial action. Dark red meat may result from postmortem retention of blood in animals that were not exsanguinated. A stable, bright red color may indicate the unwholesome addition of sulfite. Ultraviolet light may be used to visualize rodent urine and fluorescent substances produced by certain spoilage bacteria. Areas of bruising, hemorrhage, or inflammation should be readily recognized. Odors from contaminating chemicals, fish, urine, or other sources are unacceptable. When there is uncertainty about odors, a possible unwholesome odor can be enhanced by boiling or frying the meat.

Histologic examination may be used to evaluate abnormalities caused by physical, infectious, or toxic agents. Similarly, microbiologic examination may be used to evaluate spoilage and determine the presence of infectious organisms capable of causing illness in consumers. Chemical and toxicologic examinations should be done when the presence of adulterative or toxic substances is suspected. It may be necessary to increase random microbial testing of meat products to ensure their freedom from bacterial contamination.

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