Residue violative

Table 14.5 provides a sense of how frequently the PDP might need to alert the NOP of a violative residue in an organic sample. The table shows all positive samples of fresh organic produce in 2004, the residue level found and the applicable EPA tolerance. The PDP would need to flag any value over one in the column Ratio of residue found to 5% of EPA tolerance ... 

Other studies further indicate that the occurrence of endrin in the U.S. food supply is very low. In a 1990-91 FDA survey of pesticide residues in milk representing most of the U.S. supply consumed in metropolitan areas, endrin was detected at trace levels (0.0005-0.001 ppm [0.5-1.0 ppb]) in only 2 of 806 composite samples (one sample each from Atlanta, Georgia and Dover, Delaware) (Trotter and Dickerson 1993). In another statistically based FDA study in 1992-93, endrin was not found as a violative residue in any of 710 domestic or 949 imported pear samples (Roy et al. 1995). Endrin was not reported among the pesticides detected in a 1994 FDA survey of pesticide levels in 160 samples of catfish, crayfish, shrimp, trout, salmon, oysters, and various other species from important aquaculture areas of the United States (FDA 1995). Comparable results were found in similar studies conducted by the FDA in 1990-93 (FDA 1995). 

The FDA s monitoring activities rely on food sampling procedures in which the types of commodities to be sampled, and the origins of the samples, are chosen specifically to enhance the FDA s abilities to identify violative residues. FDA monitoring is therefore not a random process. 

Results from imported foods were somewhat similar, although violation rates were higher and the rates of residue detection were lower. Of the 4374 imported samples analyzed for pesticide residues, 72.0% had no detectable residues, 23.2% had detectable residues within legal limits, and 4.8% had violative residues. Violations were observed in the other category (8.1%), vegetables (6.4%), fruits (2.8%), and fish, shellfish, other aquatic products (0.3%). 

Pesticide residues are deemed violative if the residues encountered exceed the established tolerances or when residues for which no tolerance has been established are detected on the sampled commodity. In the case of imported food sample, the FDA noted that 92.9% of the violations occurred when pesticides were detected on commodities for which no tolerance was established, with the remaining 7.1% of violations occurring when residues exceeded tolerances. Violative residues from domestic food samples presented a different pattern, with 50% of the violations stemming from levels exceeding tolerance and the other 50% resulting from pesticides being detected on commodities for which no tolerance was established. 

It is critical to realize that pesticide tolerances themselves are not safety standards but rather enforcement tools for indicating whether pesticides have been applied according to directions. Violative residues result when residue levels exceed the tolerance due to the misapplication of a pesticide, or when residues at any level are found on a commodity for which a tolerance was not established (which could result from product misuse). While a few isolated cases of violative residues have resulted in human harm, the vast majority of violative residues are of little or no toxicological consequence. 

The number of animals sampled compared with the numbers produced will always astound the reader as relatively few animals are normally sampled and analyzed. It is impossible from both a logistical and cost point of view to sample huge numbers of animals. To accomplish a reasonable sampling program, an experience-based approach is both logical and realistic. This approach bases the sample size (number of animals analyzed) on what experience has shown the incidence of violative residues to be in that class of animal. Where a high incidence of violative residues is expected, a smaller number of samples is needed. 

Undoubtedly, the actual level of violative residues is somewhere between the upper and lower levels of the statistical range, and is probably closer to the... 

Earlier in this chapter, an assumption was made concerning the level of violative residues worldwide. It may be unwise to treat the residue levels in imports as an indicator of the worldwide picture, but there are few other sources of data available on which to base judgments. Fortunately, the data from the 2000 FSIS/USDA monitoring program (USDA, 2000) for imported meat products is available for easy comparison. Table 12.5 summarizes the results of residue screening for both antibiotic and sulfonamide residues in a wide spectrum of meat products from 28 countries. 

The lowest incidence of violative residuals were found in poultry and cattle, with swine and calves having the highest. 

The violation rate for antibiotics, as determined by USDA, also needs to be examined in order to discuss the regulatory concerns for antibiotic residues. Table 4 lists the violative residue rates for antibacterials in several species for the years 1979 through 1983. 

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. 

Recent Australian and Canadian studies (7-10) on residues at injection sites indicate that injection site residues of certain drugs are at levels high enough to cause public health and trade concerns. Major concerns raised by these studies are that in a significant number of cattle severe tissue reactions occur at the injection site, which adversely affect the quality of the carcass and also create an animal welfare issue. These tissue reactions lead to residues at the injection sites that persist beyond the withdrawal period whereas, in some cases, they can cause such an extremely variable residues depletion so that withdrawal periods cannot be readily established. Lesions at the injection sites are not always obvious on visual inspection and cannot be identified and discarded during trimming and processing of the carcass. Moreover, the presence or absence of violative residues in samples of kidney, liver, and muscle cannot be used as a reliable indicator of the fate of residues at an injection site. 

The use of drugs in food-producing animals inevitably results in the appearance of drug-related residues in milk, meat, and eggs. Antimicrobial residues occur more frequently than desired violative residues occur much less frequently, but in definitely significant numbers. 

In the period 1976-1978, violative residues were found in all animal species marketed (3). Although tire USDA data (Table 13.1) contain listings of several species and the frequency with which violative residues were found, nonviolative residues occuiicd in many more animals. Species with the lowest frequency were poultry and cattle, whereas swine and veal calves exhibited the highest frequency... 

Table 13.2 Violative Residue Rates (%) for Antibacterials in Several Animal Species During 1979-1983 in the United States...

The residue profile seen over the years 1976-1978 is similar to that seen in the following years. Table 13.2 lists the violative residue rates for antibacterials in several animal species for the years 1979-1983. The residue violation rate in mature cattle and poultry was very low. Chickens, in particular, had almost a zero violation rate due possibly to highly integrated US chicken-producing operations. In addition, the violation rate for turkeys was still very low although turkeys were mostly raised by independent producers. 

The kidney was the target tissue analyzed for antibiotics. When violative residues were found in the kidney, the liver of that animal was subsequently analyzed. When violative residues were also found in the liver, muscle tissue was then analyzed. For sulfonamides, the target tissue was liver. When the liver contained violative levels, muscle tissue was also analyzed. 

Table 13.7 provides information on the antibiotic and sulfonamide violations detected during 1992-1994. Sample sizes differed in the various animal slaughter classes in different years. Thus, it would not be appropriate to attribute undue significance to the number of violations detected of an individual compound. Table 13.7 does provide relevant information about the specific compounds that produced violative residue concentrations in food animals during that period. Residue violations for more than one compound might occasionally occur in the same animal. 

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