Global Maximum Residue Levels

Following the application of a pesticide product, trace residues may be present at harvest on agricultural commodities, such as fruits, vegetables, or cereal grains or in processed commodities, such as fruit juices, vegetable oils, and flours. Thus, government regulatory authorities have established maximum residue limits (MRLs) or tolerances as a check for compliance with national good agricultural practices (GAP) and to facilitate international trade. An MRL is defined as the maximum concentration of pesticide residue that is legally permitted or recognized as acceptable in, or on, a food, agricultural commodity or animal feed as set by Codex or a national regulatory authority. In some countries, including the United States, MRLs are referred to as “tolerances”, and in general the two terms are synonymous.

While the benefits of crop protection in food production are clear, there is ongoing dialogue over whether any residues that may remain on food pose a threat to human health. Before any crop protection product can be registered for use, it must pass through a rigorous legislative process that includes a scientific risk assessment of possible health effects.

MRLs are not safety limits, and exposure to residues in excess of an MRL does not automatically imply a hazard to health. MRLs for pesticides are established using verified scientific facts that take into account levels of residues in the crop following treatment according to GAP principles. MRLs are derived as a result of this process on a crop by crop basis to reflect differences in growing conditions, treatment times and other factors. They can and do vary internationally but conventions are in place to facilitate international trade. MRLs are not set on the basis of toxicological data but they must be acceptable toxicologically. When using results from supervised trials carried out under GAP to establish MRLs, it is normal to have available relevant metabolism and toxicological data. Given all the relevant background data, MRLs are usually established using the worst case scenario.