2010-2011 Dioxins and Dioxin-Like Compounds in Vegetable Oils and Cheese
The Food Safety Action Plan (FSAP) aims to modernize and enhance Canada's food safety system. As part of the FSAP enhanced surveillance initiative, targeted surveys are used to test various foods for specific hazards.
The main objective of this targeted survey was to provide baseline data regarding the presence and levels of dioxins and dioxin-like compounds in selected high-fat commodities (specifically vegetable oils and cheese) available on the Canadian retail market.
Dioxins and dioxin-like compounds are chemical contaminants that have been associated with a wide range of adverse health effects in laboratory animals and humans. The type and occurrence of these effects typically depend on the level and duration of exposure. Some of the dioxins and dioxin-like compounds have been classified by the International Agency for Research on Cancer (IARC) as known human carcinogens, others as probable human carcinogens, while others are not classifiable as to their carcinogenicityFootnote 1 in humans. The World Health Organization (WHO) considers dioxins and dioxin-like compounds a health concern on a global scale, and has recently re-iterated the need to reduce emissions of, and human exposure to, these persistent organic pollutants. Approximately 90% of a person's exposure to dioxins and dioxin-like compounds occurs through the diet, particularly through the consumption of high-fat animal tissues and dairy products. Due to recent food contamination events outside Canada, dioxins and dioxin-like compounds have gained attention in the media.
A total of 451 samples were collected and analyzed in this targeted survey. Samples included 167 domestic and imported vegetable oils and 284 domestic, intra-provincially traded cheeses. All samples were analyzed for dioxins and dioxin-like compounds (furans and polychlorinated biphenyls). All oil and cheese samples had detectable levels of one or more dioxins or dioxin-like compounds. This is not unexpected given their presence and persistence in the environment, as well as their ability to bioaccumulate in fatty tissues and biomagnify through the food chain.
The Canadian Food and Drug Regulations (FDR) state that food (with the exception of fish) which contains chlorinated dibenzo-p-dioxins is adulterated. The regulation causes enforcement challenges, as it does not reflect the large improvements that have been made to analytical methods of detection for these substances. This tolerance was established many years ago and is considered to be outdated by Health Canada. Due to the ubiquitous nature of dioxins and dioxin-like compounds in the environment, and the fact that methods of detection are becoming increasingly sensitive, "zero tolerance" is not practical and is not applied by Canada or any major trading partners. No samples in this survey had concentrations of dioxins or dioxin-like compounds in excess of European Union limits for either vegetable oils or dairy products. In fact, the levels detected were well below these limits. The levels of dioxins and dioxin-like compounds observed in this survey are unlikely to contribute significantly to the overall exposure of Canadians to these contaminants, and are not likely to be of human health concern. Follow-up activities were not deemed necessary given that no elevated concentrations were found and the levels were similar to those detected in domestic raw milk monitoring data.
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