The Food and Agriculture Organization of the United Nations (FAO) recently published a document that explores the food safety implications of environmental inhibitors, which are used to improve the production efficiency of crops and livestock while making the agrifood system more sustainable in light of mounting pressures caused by the climate crisis. In general, ensuring the food safety of environmental inhibitors requires further efforts to close regulatory and knowledge gaps.

Specifically, the publication looks at:

• Methanogenesis inhibitors, which reduce methane emissions resulting from enteric fermentation of ruminants and from other agricultural sources (such as rice paddies or manure)
• Nitrogen inhibitors, which limit the loss of nitrogen from farmlands by slowing down natural processes that lead to its leakage and volatilization.

While the use of methanogenesis inhibitors is currently mostly limited to research, several products are available on the market as nitrogen inhibitors. It is likely that the intensification of livestock farming and use of nitrogen fertilizers in the coming years will increase the application of nitrogen inhibitors. High fertilizer prices may also encourage the use of nitrogen inhibitors to minimize fertilizer demand while maintaining crop yield and quality. In many cases, information on potential residues of environmental inhibitors and/or their metabolites in food commodities is not available, which does not allow for thorough food safety risk assessments to be conducted.

The global regulation of environmental inhibitors is diverse, sometimes being covered through food and feed frameworks, and other times regulated based on other primary uses (e.g. industrial use or human medicine). As chemical residues of environmental inhibitors can occasionally be detected in food at low levels for which no regulatory limits exist, Codex Alimentarius adopted international guidelines for rapid risk analysis of such substances and agreed that Maximum Residue Limits (MRLs) for inhibitors could be considered by the Codex Committee on Pesticide Residues (CCPR) for crops and by the Codex Committee on Residues of Veterinary Drugs in Foods (CCRVDF) for animals.

Although it is necessary to fill knowledge gaps and harmonize regulation to endure the food safety of environmental inhibitors, new technological solutions can help in optimizing their application. For example, improvements in the quantification of greenhouse gas (GHG) released from livestock and farmlands can allow a more precise and simple application of inhibitors on commercial farms. However, while the development of more advanced detection methods for environmental inhibitors or their metabolites in complex matrices can strengthen food safety management, an increasing analytical sensitivity would require regulatory approaches for dealing with greater detection in food. Furthermore, technological progress in other scientific domains (i.e., in omics technologies applied to understand changes in livestock microbiome) can help investigate natural processes underlying the efficiency of mitigation strategies on methane formation and livestock performance.

Effective implementation of environmental inhibitors needs to take into account multiple factors related to costs, uncertainties, and possible food safety risks of their application for farmers, industries, and consumers. Because such factors depend on local conditions, careful evaluation on a case-by-case basis is considered the best approach to achieve required outcomes while minimizing the negative impact on other variables in the system. Current estimates indicate that costs of inhibitor application may be outcompeted by savings when considering societal benefits related to the reduction of GHG emission for human and ecosystem health. Financial incentives are one of the factors that are predicted to promote the adoption of GHG mitigation strategies.

As the trend shifts towards more sustainable agrifood systems, environmental inhibitors are a tool that may help ensure adequate nutrition for the growing world population while minimizing the impacts on the environment. At the same time, FAO stresses the importance of raising awareness of the interconnected nature of agrifood systems, so that any food safety implications are carefully considered and proactively addressed.