The Food and Agriculture Organization of the United Nations (FAO) recently published a report and accompanying technical paper on the food safety risks related to environmental inhibitors used in agri-food systems.

Environmental inhibitors are compounds used in agriculture to reduce non-carbon monoxide greenhouse gas emissions (i.e., methanogenesis inhibitors to reduce methane emissions from ruminants) or minimize nitrogen losses in soil. Although environmental inhibitors contribute to sustainability, their use requires measures to avoid potential food safety risks.

While several environmental inhibitors have received approval in various countries, regulatory frameworks governing their classification and usage differ significantly, resulting in varying data requirements for pre-market evaluation. In some markets, the sale and application of these inhibitors may occur without comprehensive regulatory oversight. Environmental inhibitors categorized as pesticides or veterinary drugs typically undergo rigorous pre-market safety assessments, which include establishing maximum residue limits (MRLs). Conversely, those classified as feed additives, fertilizer adjuvants or soil amendments may not be adequately evaluated for potential residue transfer to food products.

From a food safety perspective, regardless of what category of agricultural chemical an environmental inhibitor may be assigned to, any human health risk assessment must consider the potential residues of the compound or its metabolites in food crops and animal-derived foods. Even when environmental inhibitors are not applied directly to animals, their inadvertent uptake should be factored into the food safety assessment unless evidence indicates that the compound is not bioavailable or that any potential residues are toxicologically insignificant.

Suggested Framework for Food Safety Evaluation of Environmental Inhibitors

FAO suggests possible steps to evaluate the safety of environmental inhibitors:

1. Determine if the substance has undergone a pre-market approval process for its specific use within a given jurisdiction, ideally preceded by a food safety risk assessment
2. If the inhibitor has not been previously approved, potential food residues in crops and animal-derived food products should be assessed. This includes evaluating the likelihood of food residues in crops or animal-derived foodstuffs when used according to proposed label conditions.
3. If the use of an environmental inhibitor is likely to result in food residues, the evaluation process could involve human exposure assessment(s) according to the Codex Alimentarius guidelines, possibly followed by a full risk assessment specific to human health if the residues in question meet the exclusion criteria of the guidelines.
4. The food safety risk assessment of an environmental inhibitor could include standard aspects such as those related to the nature of chemical hazard and concentrations of residues considered safe for human health, and could lead to risk management recommendations, including, for example, the development of MRLs.

Overall, the lack of an internationally standardized classification for environmental inhibitors results in different data requirements and evaluation processes across various countries and regions, highlighting the need for a harmonized approach.