Residue animal food products, level

If a pesticide is to be applied to livestock, or will result in residues in the feed of livestock, the possibility of residues in meat, milk, poultry, and eggs arises. Data on metabolism, analytical methods, and level of residue in animal food products are needed in those cases. The same considerations of identification of the terminal residue and developing analytical methods suitable for enforcement mentioned previously also apply to residues in animal products. The tolerances for animal products are based on the tolerances on the animal feed items, the significance of those feed items in the diet of livestock, and the potential... 

Sulfonylurea herbicides are generally applied to crops as an early post-emergent herbicide. Crops that are tolerant to these herbicides quickly metabolize them to innocuous compounds. At maturity, residues of the parent compound in food and feed commodities are nondetectable. Metabolites are not considered to be of concern, and their levels are usually nondetectable also. For this reason, the residue definition only includes the parent compound. Tolerances [or maximum residue limits (MRLs)] are based on the LOQ of the method submitted for enforcement purposes and usually range from 0.01 to 0.05 mg kg (ppm) for food items and up to O.lmgkg" for feed items. There is no practical need for residue methods for animal tissues or animal-derived products such as milk, meat, and eggs. Sulfonylurea herbicides are not found in animal feed items, as mentioned above. Furthermore, sulfonylurea herbicides intentionally dosed to rats and goats are mostly excreted in the urine and feces, and the traces that are absorbed are rapidly metabolized to nontoxic compounds. For this reason, no descriptions of methods for animal-derived matrices are given here. 

With respect to veterinary medicines, the US-FDA establishes tolerances to include a safety factor to assure that the drug will have no harmful effects on consumers of the food product. The US-FDA first determines the level at which the dmg does not produce any measurable effect in laboratory animals. From this, the US-FDA determines an acceptable daily intake (ADI), and the drug tolerance and withdrawal times are then determined so that the concentrations of dmg residues in edible tissues are below the ADI. Depending on the dmg, safety factors of between 100-fold to 2000-fold are included in the calculations used to set the tolerances. 

The most serious objections to the presence of drug residues in food intended for human consumption arise as a consequence of human health considerations. With tire extensive use of drugs in animal production, residues of the parent drugs and/or metabolites have a high potential to be present in the edible animal products. The public health significance of such adulteration of the food supply is determined mainly by the level of the residues and the individual drugs they are originated from. 

For food safety purposes the overriding aim is that food contamination should be reduced to the lowest practicable level, bearing in mind the potential costs and benefits involved. Since it is difficult to establish cause and effect relationships following long-term (chronic) exposure at low concentrations, it may be necessary to base action on prudence rather than on proven harm to health. However, if this approach is to maintain the confidence of both consumers and producers of food, a rational evaluation of all relevant information is required so that the balance between the risks and benefits of veterinary drugs can be assessed. Information on the incidence of potentially harmful drug residues is fundamental to this cost-benefit analysis so too is the consumption of the commodities involved (particularly for susceptible consumers or those consumers who eat more). Account must also be taken of the potential fall in food production if a drug is controlled or prohibited, and also the animal health and welfare implications that may result from the restriction of an animal medicine for which there may be no effective alternative. 

Over a period of about twenty years the results of surveillance for veterinary drug residues in meat and animal products in the UK have provided reassurance that residues of veterinary drugs occur at very low concentrations and generally at low frequencies. Over this period repeated surveillance and improved communication and awareness of the producer and feed industry has resulted in a downward trend in the level and incidence of residues detected. However, contamination hot spots remain (e.g. animal medicated feed) and will continue to be monitored in the future. In addition, as new products are introduced into the market they will be evaluated during the licensing process to establish any risk from their residues present in human food. The UK also imports a significant amount of animal-derived food and the presence and risk to the UK consumer of residues in these products must also be considered and appropriate measures taken to protect the UK consumer. 

Cottonseeds, and their derivatives, are also known to contain hazardous pesticide residues, often at levels significantly higher than those observed in cottonseed oil. Furthermore there is strong evidence that residues consumed by animals can be incorporated into food products. In laboratory experiments, hens reared on food containing parathion (WHO la) and methamidophos (WHO ib) showed traces of the pesticides in their eggs, while cattle reared on diets containing parathion (WHO la), aldicarb (WHO la), and methamidophos (WHO Ib), passed these chemicals into their milk . 

Although many coumarins have been safely used in clinics, there are a number of reports about their unwanted side effects [241,242]. Coumarin mycotoxins in food products can pose health hazards in animals and human. At high levels in feed, these mycotoxins may cause animal toxicoses, such as aflatoxicosis. At lower levels in feed these mycotoxins may have no apparent effect on livestock production, but their residues and related substances may move up the food chain [243]. Investigations fi om several European countries indicate that, in former days, there was a connection between mycotoxins, mortality and reduced birth rate. In addition, many mycotoxins can interfere wiA the immune system, even in small concentrations, and increase susceptibility to tuberculosis and infant mortality [244]. 

World Health Organization, Comments on chloramphenicol found at low levels in animal products, in Evaluation of Certain Veterinary Drug Residues in Food, 62nd report of Joint FAOAVHO Expert Committee on Food Additives, WHO Technical Report Series 925, Geneva, 2004 (available at http //whqlibdoc. who. int/trs/WHO TRS 925. pdf accessed 11/17/10). 

The evaluation of a number of immunoassay diagnostic kits was undertaken to determine their usefulness in a regulatory analytical laboratory environment in the food, feed and pesticide areas. Four rapid enzyme immunoassay tests for the detection of aflatoxin residues at the 20 ppb level in animal feeds were compared to the official HPLC procedure. In the pesticide area, a commercial pentachlorophenol competitive inhibition assay for residues in water was investigated as to its applicability to poultry and pork liver matrices. In addition, an ELISA screening procedure for the herbicide fusilade was developed. Modifications were incorporated into the rapid immunoband 1-2 Test procedure for the detection of motile Salmonella in various food and animal feed products resulting in quicker analysis than the standard culture method. Also, a comparative evaluation of a Quik-Card Test for sulphamethazine drug residues in pork urine, liver and muscle tissue, is described. 

The FFDCA governs the establishment of pesticide tolerance for food and feed products. A tolerance is the maximum level of pesticide residues allowed in or on human food and animal feed. ... 

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