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Meat and Poultry Inspection

The Scientific Basis

of the Nation's Program

Prepared by the Committee on the Scientific Basis of the Nation's Meat and Poultry Inspection Program

Food and Nutrition Board
Commission on Life Sciences
National Research Council

Washington, D.C. 1985


Executive Summary

The American public expects that meat and poultry products in the marketplace are as safe and wholesome as technically feasible, and public opinion polls indicate that consumers generally have confidence that this is so. Indeed, meat and poultry products that pass through the inspection system are, for the most part, wholesome. The wholesomeness of the nation's meat and poultry supply depends on each link in a chain from the farm to the slaughterhouse to the table. This report addresses primarily the ways in which the Food Safety and Inspection Service (FS IS) of the U.S. Department of Agriculture (USDA) can further strengthen its part of the chain not only to reduce the number of occurrences of bacterial infections but also to reduce chemical contamination and ensure the general safety and wholesomeness of meat and poultry.

The responsibility for ensuring the safety of meat and poultry products was conferred upon the USDA through a mandate in the Federal Meat Inspection Act of 1906 and subsequent acts and amendments. These documents directed the USDA to inspect meat and poultry products that enter commerce and are destined for human consumption. The wideranging obligations of the FS IS include the assurance of a sanitary environment in slaughter and processing plants and the monitoring of all relevant stages of animal slaughter as well as meat and poultry processing procedures. The overall goal of the inspection program has been to ensure that meat, poultry, and their products are wholesome, unadulterated, and properly labeled and do not constitute a health hazard to the consumer. Toward this goal, FS IS personnel inspect meat and poultry products animal-by-animal and process-by-process in slaughterhouses and processing plants.

Slaughter inspectors rely almost completely on sight, smell, and touch to discern abnormalities in animals and carcasses. This procedure

The legal definition of these terms can be found in the Federal Meat Inspection Act (P. L. 59-242, as amended) and the Poultry Products Inspection Act (P. L. 85-172, as amended).

was designed primarily to protect consumers from grossly visible lesions or diseases. Although this labor-intensive system tends to ensure safe and wholesome products with respect to such lesions, its efficiency came under scrutiny by FS IS as science and technology advanced and the understanding of risks to human health became more defined.

In 1906, acute infections were the leading causes of human mortality and morbidity. Today, more than 60% of all human deaths in this country each year are due to cardiovascular disease and cancer--chronic diseases attributed primarily to life-style, products of industrialization, and the increasing average age of the U.S. population. Also, through improved controls and deliverance of health care to farm animals, certain animal diseases have been virtually eradicated. The importation of diseased animals into the United States has essentially been prevented, and diseases that can be transmitted from animals to humans have been curtailed or in some cases practically eliminated.

Simultaneously, the production of meat and poultry products has become increasingly complex. In contrast to the few basic cuts of fresh meat and poultry available early in this century, there is now a great variety of raw, canned, cured, dried, fermented, and frozen products. The technological growth that made these products possible has contributed to the greater need for sophistication in determining the origin and path of food-borne microbial infections. Finally, enviromental contaminants and the increasing use of chemicals in animal feeds and to some extent in processed foods have led to the presence of chemical residues in meat and poultry, some of which may be sources of potentially deleterious effects.

These changes have led FS IS to institute new programs and procedures. In the past two decades, FS IS began programs for determining microbial and chemical hazards in meat and poultry; modified inspection procedures for chickens, swine, and turkeys to increase production efficiency and decrease inspection time; and, in processing plants, started to shift the burden for maintaining the quality and safety of processed products to plant management under FS IS supervision.

Is the inspection system in place today adequate to meet new challenges? Are the initiatives taken by FS IS consistent with current concerns about public health? Can technological developments in the detection and control of deleterious microbiological and chemical agents and advances in assessment of risks to human health be better applied to meat and poultry inspection? This was the essence of the charge given by FS IS to the National Research Council's Committee on the Scientific Basis of the Nation's Meat and Poultry Inspection Program, which was established to conduct this study within the Food and Nutrition Board of the Commission on Life Sciences in conjunction with the Board on Agriculture.

The committee organized its tasks by identifying and categorizing various risks that could be presented by different parts of the production and processing operations. It then based its analysis on an assessment of the literature, discussions with experts from FSIS and the scientific community, public testimony of scientists and others from the public and private sectors, an independent survey of FSIS inspectors in meat and poultry plants, and site visits to selected plants. The assessment was limited by incomplete data, including the lack of systematic data on various phases of inspection as they relate to public health, and by the inherent difficulty of relating findings during inspection to endpoints affecting public health, such as the incidence or prevalence of human diseases.

The committee did not limit its study to those activities directly under the jurisdiction of FSIS. Rather, it considered all potential sources of health hazards in meat and poultry products, including farms, feedlots, and the ultimate destinations--the food establishments and the homes where foods are handled, stored, and cooked.

The conclusions reached and recommendations made by the committee are aimed at developing programs to ensure that the inspection system keeps pace with advances in knowledge and is efficient with regard to public health protection. The committee has also identified characteristics that in its judgment constitute an optimal meat and poultry inspection program.


The meat and poultry inspection program of the FSIS has in general been effective in ensuring that apparently healthy animals are slaughtered in clean and sanitary environments. FSIS has made progress in reducing risks to public health from conditions that can be observed during antemortem and postmortem inspection and that can be evaluated during processing. However, substantial challenges continue to

confront the agency. Some aspects of the inspection system are poorly defined in terms of objectives relevant to public health. A risk-based allocation of resources, supported by modern technology and a systematic evaluation of the program, would be valuable.

Public Health Risks Related to Biological Agents

It is well established that species of Salmonella and Campylobacter are major causes of diseases transmissible to humans through the consumption of meat and poultry products, and the committee concluded that current postmortem inspection methods are not adequate to detect these organisms. For example, meat and poultry were implicated in 1,420 of the 2,666 food-borne disease outbreaks from known sources reported to the Centers for Disease Control (CDC) between 1968 and 1977.

Salmonella contamination accounted for approximately 26% of all food-borne outbreaks in 1981. Meat and poultry were also responsible

for 4 out of 23 outbreaks due to species of Campylobacter (a less easily detectable organism) reported to the CDC during 1981 and 1982. Of particular concern to the committee is the risk presented by food-borne microbial infections to susceptible subgroups such as young children and the elderly. Pathogenic microorganisms reside in the gastrointestinal tracts and on external surfaces of food-animals and cannot be detected by the usual organoleptic procedures (i.e., sight, smell, and touch) used during inspection. Therefore, human pathogens such as species of Salmonella, Campylobacter, Clostridium, and Staphylococcus are not ordinarily identified during slaughter.

Microbial contamination is common among fresh foods, including meat and poultry. Hazards from such contamination have been minimized, however, by FSIS inspection and by the USDA's educational efforts, which have resulted in improved handling of foods in slaughter and processing plants, food service facilities, and homes. Microorganisms in raw meat and poultry products can multiply, spread, and perhaps cross-contaminate other foods in food-service establishments and homes unless the products are handled properly in the plant, during transport, in retail outlets, and by the consumer after purchase. Proper handling and cooking are important to avoid contamination of meat and poultry by species of Salmonella and Campylobacter; for pork products that might contain the food-borne parasite Trichinella spiralis, proper cooking is essential.

Slaughterhouse employees are at especially high risk because of their exposure to infectious organisms that cause brucellosis and psittacosis--infections that humans can acquire by direct contact with diseased animals. Although an eradication program has effectively reduced the incidence of brucellosis in most of the U.S. population, the disease still occurs to some extent among slaughterhouse employees.

Recommendations. The committee recommends that FSIS intensify its current efforts to control and eliminate contamination with microorganisms that cause disease in humans. Such efforts should include evaluation of rapid diagnostic procedures for detecting microorganisms, especially species of Salmonella and Campylobacter, and education of the general public, health care personnel, educators, and extension service workers in the safe handling of meat and poultry. The committee also recommends that meat handling practices in plants be monitored and evaluated in an attempt to prevent the occurrence of meat- and poultry-derived infections among plant employees. Although their prevalance is low, these infections present significant and avoidable occupational hazards. Better epidemiological surveillance and coordination of efforts to eradicate these diseases are also needed. (See Chapters 3, 6, and 7 for a detailed discussion of biological agents in meat and poultry that pose a risk to human health.) Public Health Risks Related to Chemical Agents

The committee concluded that although significant strides have been made in protecting the public against exposure to hazardous chemicals

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