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2010-2011 Propylene Oxide in Foods


The Food Safety Action Plan (FSAP) aims to modernize and enhance Canada's food safety system. As a part of the FSAP enhanced surveillance initiative, targeted surveys are used to test various foods for specific chemical and microbiological hazards.

The main objective of the propylene oxide (PPO) in selected foods targeted survey was to generate baseline surveillance data on the levels of PPO in non-starchy foods potentially treated with fumigant, specifically cocoa, nutmeats, dried herbs, dried fruit, and spices.

Propylene oxide is a highly volatile chemical which does not occur naturally in the environment. It is manufactured for use as a fumigant for food and for industrial applicationsFootnote 1. PPO has been used as an insecticide and antimicrobial fumigant in dried fruits, nuts, and spices in the Unites States for over fifty years. While it is not registered for use as a fumigant/pesticide in Canada, Canadians may be exposed to this chemical via consumption of imported finished foods and food ingredientsFootnote 2.

Although the primary route of human exposure to propylene oxide is by inhalation, foods treated with PPO may contain residues of this fumigant unless adequate ventilation/aeration of the treated commodity is providedFootnote 3. According to the toxicological studies submitted to Health Canada's Pest Management Regulatory Agency (PMRA), evidence of the potential for propylene oxide to cause cancer in animals was identified after lifetime exposure. As such, a cancer risk assessment was conducted, which demonstrated that consumption of PPO-treated food commodities originating from the US will not pose a human health concern to any segment of the Canadian population, including infants, children and seniors.

Although not approved for domestic use, PMRA, under the authority of the Pest Control Products Act in 2009, established a maximum residue limit (MRL) of 300 parts per million (ppm) for PPO in almonds to permit the import and sale of almonds that may contain this residue. PMRA is currently in the process of establishing new MRLs for PPO in/on the entire tree nut crop group and herbs and spices crop group. These values are expected to be consistent with established residue tolerance levels in the U.S. for nutmeats, cocoa, dried fruits, and dried herbs/spicesFootnote 4. Other PPO-treated food products imported into Canada are currently subject to the General Maximum Residue Limit (GMRL) of 0.1 ppm under Division 15 (B.15.002(1)) of Health Canada's Food and Drug Regulations.

One hundred samples of dried spices and herbs, dried fruit products, cocoa powder, and nuts (of both domestic and imported origin) were analyzed for PPO in 2009-2010. Additionally, nine hundred and sixty-four samples of dried spices and herbs, dried fruit products, cocoa and chocolate products/powders, and nuts (of both domestic and imported origin) were analyzed for PPO in 2010-2011. Propylene oxide was not detected in any sample tested. The overall compliance with the MRL for almonds or the GMRL (as applicable) was 100%.

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