Animals as Sentinels of Environmental Health Hazards (1991) / Chapter Skim
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3. Food Animals as Sentinels
3. Food Animals as Sentinels
Pages 53-68
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From page 53... ...
Food-monitoring programs are designed to monitor hazards to human consumers; they produce data useful for signaling environmental contamination in the geographic area of the food animals' origin and for predicting human risk associated with consumption of the sentinel animals themselves. Food-monitoring programs generate information on contaminants in tissues; for example, they provide information on tissues infected with microorganisms and their toxins and with toxicants from the environment.
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From page 54... ...
The federal and state programs that monitor food animals for chemical residues do so primarily to determine adherence to environmental regulations aimed at protecting humans from harmful chemicals in their food and at protecting animals from direct and indirect effects of chemical contaminants. The principal federal agencies that operate chemical-residue monitoring programs for protection of the human food supply are FSIS and FDA.
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From page 55... ...
The committee concluded that "the most effective way to prevent or to minimize hazards presented by certain infectious agents and chemical residues in meat and poultry is to control these agents at their point of entry into the food chain, i.e., during the production phase on the farm and in feed lots." The Food and Nutrition Board committee noted the absence of an effective national surveillance system for monitoring the disease status of food animals, as well as the absence of an adequate mechanism for tracing infected or contaminated animals to their source. For example, the probability of successfully tracing diseased or contaminated animals to their producers was approximately 10% for cattle and 30% for swine.
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From page 56... ...
AS ANIMALS AS SENTINELS TABLE 3-1 November 1987 Livestock Slaughter Report for the USDA Food Safes and Inspection Service Category of Livestock Number Number Slaughtered Condemned Bulls and stags 41,238 90 Steers 987,866 812 Cows 409,044 6,452 Heifers 665,466 569 Bob veal 84,939 1,532 Formula-fed veal 57,716 75 Non-formula-fed veal 10,048 35 Calves 20,625 37 Mature sheep 19,129 1,345 Lambs and yearlings 332,612 1,206 Goats 15,486 51 Barrows and gilts 4,455,923 4,989 Stags and boars 38,061 220 Sows 183,411 740 Horses 23,159 91 Young chickens 375,150,905 4,196,327 Light fowl 11,406,615 408,323 Fryer-roaster turkeys 366,595 4,705 Young turkeys 21,746,540 243,020 Old breeder turkeys 119,274 3,267 Ducks 1,799,462 22,457 Geese 59,114 891 Rabbits 43,215 156 Capons 100,904 3,183 Heavy fowl 2,605,871 67,162 Young breeder turkeys 103,751 2,082 Others (guineas, squabs, pigeons) 234,935 1,255 Source: USDA, 1987 National Animal Health Monitoring System USDA recognizes the need to quantify diseases in food-producing areas
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From page 57... ...
Reported events might be used to identify inappropriate use of drugs in food animals and might be linked to residue data to identify trends. Measurement of environmental contaminants is not part of the current NAHMS program, but its utility could be greatly enhanced if it expanded its program to monitor for the appearance of environmental contaminants, as signaled by adverse health or behavioral effects.
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From page 58... ...
For example, if NAHMS data indicated potential human exposure to a toxicant, an epidemiologic survey, including blood sampling, of human populations could be carried out (Teske and Paige, 1988~. Market Cattle Identification Program The Market Cattle Identification (MCI)
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From page 59... ...
Unlike the programs described above, the Total Diet Study analyzes dietary composites, not individual animals. A notable example of the usefulness of this study involved the detection of a residue of the preservative and fungicide pentachlorophenol in unflavored gelatin in a 1975 study.
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From page 60... ...
at slaughter (Teske and Paige, 1988~. When residues exceed acceptable limits, FDA can notify or investigate feed producers and alert the public to the potential dangers of ingesting contaminated food productse Sheath log Shellfish monitoring programs have historical and contemporary value and show well how food-chain monitoring aids in protecting human health.
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From page 61... ...
are examples of successful national information-collection programs. As part of NAPINet, the National Animal Poison Control Center was established at the University of Illinois College of Veterinary Medicine in 1978.
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Environmental studies found high concentrations of organic mercury compounds in sediment from Minimata Bay, in the effluent from a nearby factory where mercuric chloride was used in the catalytic process of vinyl chloride production, and in fish taken from this area. A ban on fishing in Minimata Bay eliminated the disease in cats and people.
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From page 63... ...
Epidemiologic studies revealed that the protein supplement fed to the cows was contaminated with a fire retardant that contained polybrominated biphenyls (PBBs)
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AM4LYTIC EPIDEMIOLOGIC STUDIES Sheep and Hem Metals A recent study of sheep living around a zinc smelter in Peru demonstrated the feasibility of establishing animal sentinels around point sources of pollution (Reif et al., 1989~. Heavy-metal exposures were documented in sheep pastured up to 27 km downwind from the smelter.
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From page 65... ...
calculated human exposure to contaminants in fish from the Great Lakes; the calculations of exposure were used to derive estimates of risks of cancer and noncancer health effects. Some critics regard this approach as premature, although identification of hazards to human health was the primary purpose of conducting the monitoring programs, which were initiated in the 1960s.
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From page 66... ...
Those animals provide continuous data on radioactivity in northern Sweden; the data have been used to regulate human exposure. In many food-monitoring programs, the proportion of shipments sampled is very small.
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From page 67... ...
FOOD ANIMALS AS SENTINELS 67 although the program would need to be expanded, the tissues already are collected and tested, and unused portions of blood could all be used to test for pesticide and herbicide residues, heavy metals, and various other environmental contaminants. Such an expanded system would provide health officials with a widespread mechanism for monitoring pollutants and ultimately for protecting public health from environmental hazards.
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