Are veterinary drug maximum residue limits protectionist? International evidence

We analyze the distribution of maximum residue limits (MRLs) on veterinary drugs used in animal production and aquaculture in a global context of food consumption and trade. We compare MRLs by drug–commodity pairs for a large set of countries, commodities, and drugs. We find that international standards by Codex Alimentarius only cover a small fraction of the drug-commodity pairs. We compare countries’ MRLs to Codex MRLs when they exist and look at potential deviations from the science-based MRLs in either direction (more or less stringent than Codex). For drugs without Codex standard, we look at deviation from median values. When Codex MRLs exist, variation and stringency above codex MRLs are minimal, a somewhat surprising and hopeful finding. Little protectionism prevails when a Codex standard exists. We find higher variation when Codex standards do not exist. We test for significant differences in MRL variation for cases with and without a Codex MRL and find robust evidence of higher variation for the latter. Increasing the institutional capacity of Codex for establishing a larger set of MRLs would reduce the heterogeneity of MRLs across countries.