Contamination of animal feeds

On occasions, animal feed has been suspected of deliberate contamination. Incidents involving contamination of animal feed by industrial by-products such as polycylic aromatic hydrocarbons (PAHs) and combustion products such as dioxins are not uncommon. A problem with animal feed is that there is sometimes inadequate control over the provenance of feed constituents. For example, spent cooking oil from food-processing plants is a legitimate feed component. Unfortunately, the temptation for the unscrupulous to dispose of other unwanted oils in this way is too great for some. In many cases such adulterants are probably diluted to such an extent that they are undetectable by conventional chemical analyses. Nevertheless, they may still represent a longterm cumulative hazard to consumers of products from animals fed on such material. 

In the period prior to launch of the White Paper, the European Community had experienced consumer disquiet due to a number of food scares. These included contamination of animal feed, bovine spongiform encephalopathy (BSE), concern about the use of antimicrobial feed additive used to increase productivity in animal production, and genetically modified food. The White Paper identified the need to reestablish consumer confidence in the European food supply and to reassure trading partners of the Communities ability to regulate and control die safety of its food supply. 

Contamination of animal feed or foods by PBBs has been reported only in connection with the Michigan PBB incident [2]. 

Historically, occurrences of feedstuffs becoming contaminated in transport vessels were primarily because of the failure to clean the vessels after use. Failure to clean transport vessels or leaving substances to be commingled with animal feedstuffs could be an act of terrorism or criminal action that could cause significant contamination of animal feed ingredients that could have broad dissemination in animal feedstuffs and contaminate human foods. 

Surveys of residues in foods have sometimes detected coccidiostats in foods derived from species in which their use is not authorised. This can be the result of misuse or it can be due to unintentional cross-contamination of feed from a batch containing a coccidiostat with one that is intended to be cocci-diostat-free. Normal practice at feed mills can result in some carry-over of a small amount of an earlier batch of feed into the next batch to be mixed. The level of cross-contamination resulting from this would be expected to be less than 10%. A risk assessment showed that the level of residues of each coccidiostat in edible animal tissues was sufSciently low that the exposure of consumers would not exceed the ADI of each coccidiostat. It was concluded that such cross-contamination of animal feeds would not be expected to adversely affect the health of consumers. However there were a few instances in which a high level of cross-contamination by feed additives containing high levels of coccidiostats could cause some non-target animals to be exposed to levels of coccidiostats that were potentially detrimental to their health. Therefore the EFSA Panel on Contaminants in the Food Chain recommended limits for levels of cross-contamination of lasalocid and maduramycin in some foods and these limits have been introduced into legislation. Cross-contamination limits were not set for those coccidiostats that were unlikely to leave harmful levels of residue. 

In the enforcement phase of testing, IDA may also conduct follow-up investigation at the animal producer level to uncover the original source and cause of the contamination problem. This often results to seizure of animal feed or seizure and condemnation of carcasses. In accordance with the federal law, offenders may face prosecution if found guilty of contravening FDA tolerance levels. In addition, farmers harboring violative residues may find future shipments impounded unless they can clearly demonstrate compliance with residue standards. 

The accidental contamination of chicken feed with dioxin contaminated fat in Europe shows how food exposure could occur. Because dioxin does not cause immediate symptoms, authorities did not discover the contamination for months in 1999, and Europeans probably consumed the dioxin in chicken meat and eggs sold that year. One lesson learned from this event is that physicians and public health officials need to recognize and report unusual or suspicious health problems in animals as well as humans (1). The 1999 West Nile virus epidemic in birds and humans in New York City reinforced this lesson. Fortunately, biological and chemical contamination of public water supplies will usually pose little risk due to dilution by the large volume of water. 

Indirect food additives, manufacturing of foodpackaging material Temporary tolerances for residues of PCBs as unavoidable environmental or industrial contaminants Finished animal feed for food- Yes 0.2 ppm FDA 1998b 21 CFR 509.15 FDA 1998c 21 CFR 509.30... 

Animal products contain important nutrients in bioavailable form, essential for growth and proper physical and mental development. Milk and milk products are the major source of essential nutrients in diet. Thus, knowledge of the mineral concentrations in milk samples and milk products is of particular interest. This becomes especially important in view of the wide variability in mineral content of milk due to numerous factors affecting milk composition, such as lactation (the composition of milk varies considerably during lactation, with the major changes usually occurring soon after the start of the lactation period), the breed of animal, climate, season, dietary composition of animal feed and soil contamination. Also, the mineral content may vaiy because of its handling by humans. ... 

Detection and identification of toxin and drug contamination in animal feeds and foods. 

A close investigation of a disease causing severe losses of young turkeys and other domestic animals has revealed that death is attributed to aflatoxin contamination of the feed (11, 242]. The aflatoxin contents are very low in even the most toxic sample. Nevertheless, their characteristic strong fluorescence in ultraviolet light provides a method for monitoring these toxic and carcinogenic compounds. 

It became clear that animals for slaughter become infected from contaminated feeds, water and environmental sources, e.g. insects and rodents. Because decontamination of animal feeds, recommended in the early 1950s, was not applied, autonomous Salmonella cycles have become established. The introduction of mandatory pelletisation of all mixed feeds would, therefore, not lead to any immediate improvement. This does not detract from the fact that this is a vital step in controlling salmonellosis in the long run. 

Humans can be directly exposed to coccidiostats as a result of handling them or feeds containing them. Such exposure is likely to be mainly by dermal and inhalation routes. Consumers of animal-derived foods can be orally exposed to residues of coccidiostats in food. These residues may be the result of intentional treatment of the animals with coccidiostats or the result of unintentional contamination of their feed. 

Autopsies of animals in the Meuse Valley, Donora, and London episodes described in Chapter 16, Section III, revealed evidence of pulmonary edema. Breathing toxic pollutants is not, however, the major form of pollutant intake for cattle ingestion of pollution-contaminated feeds is the primary mode. 

In the case of animals we are concerned primarily with a two-step process accumulation of airborne contaminants on or in vegetation or forage that serves as their feed and subsequent effects of the ingested herbage on animals. In addition to pollution-affected vegetation, carnivores (humans... 

Tolerance of animals for fluorides varies, dairy cattle being most sensitive and poultry least (Table 8-3). Fluorosis of animals in contaminated areas can be avoided by keeping the intake levels below those listed by incorporating clean feeds with those high in fluorides. It has also been determined... 

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