We use a lot of acronyms in our daily life! You may have heard "MRL" before, especially if you grow an edible crop. But do you know what it means?

MRL stands for "Maximum Residue Limit", which refers to the maximum amount of pesticide residue that may remain on food after a pesticide is applied as per label directions and which can safely be consumed.

When you apply a pesticide to a crop, a residue may still remain on that crop at harvest time. Health Canada's Pest Management Regulatory Agency (PMRA) reviews studies that show residue levels found in food (raw and processed) when the pesticide was used according to label directions. The PMRA assesses whether the food with these pesticide residues can safely be consumed. The PMRA sets the MRL well below a level that may cause harm to human health. The MRL is specific for every pesticide-crop combination and is regulated by the PMRA through the federal Pest Control Products Act. Until an MRL is established, the PMRA uses a default MRL of 0.1 ppm.

The Canadian Food Inspection Agency (CFIA) is responsible for enforcing the MRLs established by the PMRA. The CFIA conducts an Agricultural Chemical Residue Sampling Program that involves monitoring and compliance. Every year they test about 10,000 samples of imported and domestic fruits and vegetables for pesticide residues.

OMAFRA's Food Inspection Branch also conducts an annual Produce Food Safety Monitoring Program which involves collecting Ontario grown fresh fruits and vegetables and testing them for pesticide residues and pathogenic organisms (e.g., Listeria monocytogenes, E. coli O157:H7). Samples are randomly collected from retail points of sale across the province including roadside stands, farmer's markets, wholesalers and farm gate sales. About 250 samples are analyzed for over 500 agricultural chemicals and compared to Health Canada's MRLs. A risk based approach is used to determine the type and number of commodities collected. Factors taken into consideration include consumption patterns, cooking patterns, outbreak data and history of non-compliance. Chemical non-compliance triggers notification letters and potentially an on farm visit by a Risk Management Specialist depending on the outcome of a risk assessment. Ministry staff work with the grower to determine the source of the contamination and to implement preventive measures. Summaries of Food Safety Monitoring Program results can be found at Ontario.ca/producesafety.

Applying a pesticide at a higher rate or applying too many applications or too close to harvest are some scenarios that can lead to a violation of an MRL (residues that are too high). No one wants a violation. If you decide to apply a pesticide, it is important that you follow the most current label directions, because labels can change.

When exporting your food product, you need to be aware of the importing country's MRLs because their MRLs may be different than our Canadian MRLs. Know which pesticides have lower MRLs or no established MRLs. You may want to avoid using these pesticides and choose an alternative.

There are various ways you can find MRL information:

  • Search PMRA's MRL database. This database provides information on established Canadian MRLs. You can search by individual pesticide-commodity combinations or by multiple pesticides and crops. In this database, you may find MRLs for certain pesticides or uses that are not registered for use in Ontario (Canada). These MRLs are for food products that are imported into Canada and that may contain these pesticide residues. It does not mean you can use that pesticide on that particular crop here. Always refer to the current Canadian pesticide label for uses allowed in Ontario (Canada) (PMRA label search database).
  • Global MRL database. This database provides free access to U.S. MRL information. Check with your grower organization for other countries' MRL information as they may have access.
  • Agricultural Chemical Companies can provide MRL information for their products. The companies' contact information are found on the pesticide labels, company websites and in our OMAFRA crop protection guides.