US Food and Drug Administration regulatory pesticide residue monitoring of human foods: 2009-2017

Pesticides such as insecticides, fungicides, and herbicides can protect crops from insects, fungi, weeds, and other pests but must be applied following label instructions so that the pesticide residues in human and animal foods do not exceed maximum residue limits (MRLs, known in the US as pesticide tolerances). The US Food and Drug Administration (FDA) collects and tests foods for pesticide residues to enforce compliance with tolerances and publishes annual reports on pesticide testing results. In this study, results for over 56,000 human food samples collected and analysed under the FDA pesticide residue monitoring programme between fiscal years (FY) 2009 to 2017 were reviewed to identify trends not apparent in annual reports. The overwhelming majority of these samples, 98.0% of domestic and 90.9% of import human foods, were compliant with federal standards. Although herbicides may be more widely used, the 10 most frequently detected residues were insecticides and fungicides. On a yearly basis, the violation rate for imported samples is 3–5 times higher than the rate for domestic samples. The import violation rate increased over time, as did the number of residues detected. Targeted sampling of foods with higher commodity-specific violation rates appears to be a major contributor to the increased violation rate. Mismatches between US tolerances and international MRLs can lead to violations; this was especially marked for rice. Overall, the majority of violations are due to residues of pesticides not authorised for use in the US (lack of tolerances). While DDT continues to persist in the environment and was found in 2.2% of domestic samples and 0.6% of imported samples, 42.3% of DDT-positive samples were below the limit of quantitation. The trends and analyses identified in this paper may help FDA plan future sampling and continue to protect the food supply.