Sécurité sanitaire et qualité des aliments

Study looks at the international harmonization of pesticide maximum residue limits in rice


Despite longstanding efforts towards international harmonization of allowable thresholds for pesticide residues in foods, differences in national implementation of maximum residue limits (MRLs) continue to exist, raising questions with regard to their impact on trade. To shed light on this complex issue, FAO conducted an analysis, using rice as a case study. The publication, Understanding international harmonization of pesticide maximum residue limits with Codex standards, was released on 12 August 2020.

The findings of the study are organized in two parts:

Part A 

The first part looked at the international harmonization of pesticide MRLs and its effects on trade, reporting that many MRLs registered at national level do not have corresponding Codex MRLs. The analysis also revealed that the majority of Codex pesticides MRLs in rice are not adopted at national level. The level of harmonization with Codex pesticides MRLs in rice varies greatly across countries and regions. The economic analysis, conducted using a gravity model, found that MRLs can affect trade in two ways: MRLs stricter than Codex in the importing country are associated with relatively more rice imports, possibly reflecting strong consumer food safety awareness in those countries. Whereas, if MRLs on the importer side are stricter than those on the exporter side, then exporters may incur additional costs in order to comply with the importing country’s applied standards and dampen their exports to the markets with stricter MRLs.

“These higher costs may impede exports from low- and middle-income countries to countries with regulations that are more strict than their own,” said Georgios Mermigkas, FAO Economist and co-author of the study. He noted that these countries account for more than 96 percent of global rice production and a similar share of world rice consumption.

Part B 

The second half of the publication explores the reasons behind the various levels of harmonization, investigating the risk assessment procedures and risk management policies that may lead to divergent MRLs. “Considerable variation has emerged in how countries are aligned with the FAO/WHO Joint Meeting on Pesticide Residues (JMPR)/Codex process for the development and establishment of pesticide MRLs,” said Vittorio Fattori, FAO Food Safety Officer and co-author of the study. In general, he added, many of the differences observed in risk assessments do not seem to have a significant impact on the overall outcome of the pesticide safety evaluation.

Some of the major differences in MRLs and residue definitions are due to, for example, the consideration of different data for the various countries/region and to inconsistency among the commodity descriptions in different countries. Automatic harmonization with Codex MRLs is not the norm because such practice is not embedded in national legislations. For MRLs not established at national level, the default practice is, in general, to set a default value, usually at the limit of quantification, or not to establish any tolerance level or MRL.


The study shows that any changes towards further international alignment of pesticide MRLs for rice to facilitate trade will have to find a balance between the demand for strict food safety regulation on the importer side and the costs incurred on the exporter side. Different steps could be taken by countries towards improving harmonization with Codex standards. For example, Codex MRLs could be taken into consideration in the absence of national MRLs.

The findings of this analysis could be used to stimulate an international dialogue to improve harmonization, according to the authors. For the optimal functioning of the Codex MRL standard-setting process, countries would need to notify whenever they have reservations and are not in a position to adopt a newly established Codex MRL. Attention should also be given to low- and middle-income country needs for better and more active participation in the Codex standard-setting process.

MRLs define the maximum concentration of a pesticide residue to be legally permitted in food commodities and animal feeds, ensuring that food is safe for consumers and public health is protected.

Download the publication here

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