in the United States over the past four decades have shown that the number of samples with detectable pesticide concentrations have fallen—even when improved analytical methods with increased sensitivity have been used.
Recognizing the wide variation in sampling and analytical methods, size, and the overall design and objectives of existing residue testing programs, the committee requested residue data for its review from a variety of sources, including FDA, state regulatory agencies, the infant formula and baby food industries, the food processing industry, retail distributors, the agricultural chemical industry, and commodity associations. The most comprehensive and best recorded data were those collected through FDA's market basket sampling and analysis.
No single data bank provides ideal residue values. Residue analyses are complex, difficult to perform, and expensive. All data should be judged within this perspective. It is therefore important that samples be carefully identified and described, their processing and application history defined, and the capability and periods of analyses provided. Evaluation of the data bases provided to the committee emphasized the need for uniform sampling, collection, and reporting to reflect adequately the data's quality.
The FDA monitors pesticide residues in all food other than meat, milk, and eggs. The agency's monitoring program is not designed to determine dietary exposure to pesticides. Rather, its objective is to enforce compliance with EPA's tolerance levels. The usual point of sampling is the commercial warehouse, border crossings, points of importation, or some similar point after, but as close as possible to, the harvest. Table 6-5 shows the total number of samples and positive detections in FDA's surveillance program in 1988 and 1989. The ranges in both parameters are so wide that comparisons are very difficult. For example, dicrotophos samples were 100% positive, but the number sampled (15) is too small to be representative. For those pesticides with larger (>1,000) sample numbers, the highest percentages positive were found for benomyl (28.5%), EBDC (11.6%), and acephate (9.6%).
The committee reviewed FDA residue data on more than 100 different pesticides and selected a smaller subset for further analysis. The purpose was to isolate specific compounds for more extensive studies. Criteria for evaluation were