Canadian Standards ("Maximum Limits") for Various Chemical Contaminants in Foods

Background
Contaminant Standards

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Background

Health Canada's Food Directorate is responsible for the assessment of risk to human health from exposure to food-borne chemical contaminants. When an unacceptable risk is identified, appropriate "risk management" measures must be taken to reduce or eliminate the risk of adverse health effects from exposure to the chemical. One risk management measure is the establishment of "maximum levels" for chemical contaminants in retail foods. Maximum levels may be established by Health Canada and are enforceable by the Canadian Food Inspection Agency.

Certain maximum levels appear in the Canadian Food and Drug Regulations, where they are referred to as "tolerances." There are also a number of maximum levels that do not appear in the Regulations. These are referred to as "standards."

Maximum levels exist for a number of chemicals and retail foods, although the list is limited. There are several reasons for this. The finding of a chemical in food does not automatically lead to the conclusion that there is an unacceptable health risk to humans. The chemical may be at such low levels that it does not pose an unacceptable risk and therefore, risk management (e.g. the establishment of a maximum level) is not required, although there may be continued surveillance to monitor levels over time.

Even if a risk is identified and risk management is required, the establishment of a maximum level may not necessarily be considered the best approach to reducing or eliminating the risk of exposure to the chemical in food. For example, the presence of a contaminant in a food may be the result of an incident that was isolated (either in terms of time or in geographic location) and that could have been avoided. In this case, appropriate risk management may involve removal of the contaminated food from retail shelves and/or corrective action at the food manufacturer or farm level to ensure that such contamination does not occur again. Short-term monitoring to ensure that the corrective action was successful would be required but the establishment of a maximum level may not be considered necessary.

Maximum levels are established in an effort to reduce exposure to a particular contaminant. Exposure is affected by (1) the concentration of the chemical in food; and (2) the amount of the food consumed. Therefore, both the concentration and the amount of food normally consumed by an individual must be considered when establishing a maximum level. As a result, maximum levels for a particular chemical in various foods may differ depending on the food.

Consideration must also be given to the availability of the food itself when establishing a maximum level. A needlessly restrictive maximum level (from the perspective of protection of human health), while possibly further reducing potential exposure to a chemical, could result in a severe reduction in availability of a food that may be an important source of nutrients.

The absence of a maximum level for a particular chemical contaminant does not mean that it is exempt from the Food and Drug Regulations. If a chemical is found in a food, regardless of whether or not there exists a maximum level, Health Canada may conduct a "human health risk assessment" to determine whether there is a potential risk to human health and whether risk management measures must be taken.

Contaminant Standards

The following is a list of Canadian standards (maximum levels) for various chemicals in specified retail foods.

Canadian tolerances for aflatoxins, agricultural chemicals, arsenic, dioxins (under review), fluoride, lead, and tin appear in the Food and Drug Regulations.

Guidelines have been established based on the best available scientific information but may be modified, in response to new scientific information, when necessary and in consultation with the Canadian Food Inspection Agency, to ensure that Canadians are not exposed to levels of chemical contaminants that could pose a potential health risk. While the following list will be updated from time to time, Health Canada should be contacted for the most up-to-date status of the standards (Bureau of Chemical Safety contact information).

CONTAMINANT	Standard
	Maximum contaminant concentration	Food
ASP Toxin (Domoic acid) ASP = Amnesic Shellfish Poisoning	20 μg/g	In shellfish (edible portion)
Deoxynivalenol (Vomitoxin)	2.0 ppm (under review)	In uncleaned soft wheat for use in non-staple foods
	1.0 ppm (under review)	In uncleaned soft wheat for use in baby foods
DSP Shellfish Toxins (okadaic acid and/or DTX-1) DSP = Diarrhetic Shellfish Poisoning	1 μg/g	In digestive tissue
	20 ug/100 g	In shellfish soft tissue
Ethyl carbamate	30 ppb	In table wines
	100 ppb	In fortified wines
	150 ppb	In distilled spirits
	400 ppb	In fruit brandies and liqueurs
	200 ppb	In sake
Glycoalkaloids (GA)	20 mg/100g total GA	In potato tubers (fresh weight)
Histamines	20 mg/100 g	In anchovies, fermented fish sauces and pastes
	10 mg/100 g	In other fish and fish products
3-MCPD (3-monochloropropane-1,2-diol)	1 ppm	In Asian-style sauces such as soy, oyster, mushroom sauces, etc.
Mercury	0.5 ppm total mercury	In the edible portion of all retail fish, with six exceptions (see the 1 ppm standard below). [See also advice on canned white/albacore tuna via the "Mercury webpage"]
	1 ppm total mercury In Force as of July 11, 2007	The edible portion of escolar, orange roughy, marlin, fresh and frozen tuna, shark, and swordfish [See advice on these six types of fish via the "Mercury webpage"]
PAHs (polycyclic aromatic hydrocarbons)	3 ppb B(a)P Toxic Equivalents B(a)P = benzo(a)pyrene	In olive-pomace oils (this is a unique type of oil, distinct from other olive oils such as virgin olive oil)
PCBs (polychlorinated biphenyls)	(under review)	Fish Meat & Dairy Products Eggs Poultry
PSP Toxin PSP = Paralytic Shellfish Poisoning	80 ug/100 g meat	In shellfish (edible portion)
Pectenotoxins (a group of shellfish toxins)	1 ug/g	In digestive tissue
	20 ug/100 g	In shellfish soft tissue