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Food and Nutrition

Canadian Standards (Maximum Levels) for Various Chemical Contaminants in Foods

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

When establishing maximum levels for contaminants in food, consideration must also be given to the availability of the food, the nutritional value of the food, and if the food is a staple in the Canadian diet.

The toxicity of the chemical in question must also be considered in the establishment of maximum levels for contaminants in food, because different chemicals affect human health in different ways. For example, a certain level of exposure to one food contaminant may not have an adverse impact on human health, whereas similar exposure to a different contaminant may be very harmful.

There are a limited number of retail foods for which maximum contaminant levels have been developed. 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. Most chemicals are found in food at such low levels that they do not pose a safety concern and therefore the establishment of maximum levels is not required. Levels of chemicals in food are monitored through continued surveillance activities by both Health Canada and the Next link will take you to another Web site Canadian Food Inspection Agency. Data from this surveillance are used to help identify potential contamination issues and, when warranted, appropriate risk management strategies are developed.

Even if a health risk is identified and risk management action is required, the establishment of a maximum level may not necessarily be considered the best approach to reducing the risk associated with the food-borne chemical. 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 geographical 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.

The absence of a maximum level for a particular chemical contaminant does not mean that it is exempt from the Food and Drugs Act and Food and Drug Regulations. Part I, Section 4 of the Next link will take you to another Web site Food and Drugs Act states that no person shall sell an article of food that has in or on it any poisonous or harmful substance, is unfit for human consumption, or is adulterated. 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 if there is a potential risk to human health and whether risk management measures are required.

Contaminant Standards

The following table lists Canadian standards (maximum levels) for various chemicals in specified retail foods.

Canadian tolerances for some additional chemical contaminants appear in the Next link will take you to another Web site Food and Drug Regulations in Sections B.01.046, B.01.047, and in Table 1 of Division 15. Note that the tolerance levels in Division 15, Table 1 are in the process of being updated by Health Canada.

With respect to other types of chemicals, pesticides are regulated under the Next link will take you to another Web site Pest Control Products Act and maximum residue limits for pesticide residues in/on domestic and imported food are established by Health Canada's Pest Management Regulatory Agency. The Veterinary Drug Directorate develops maximum residue limits for veterinary drugs that could be present in a food derived from a food-producing animal that has been treated with such a drug.

Standards 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 in their diet that may pose a safety concern (Bureau of Chemical Safety contact information).

Table 1: Canadian standards (maximum levels) for various chemicals in specified retail foods
Contaminant Standard
Maximum contaminant concentration Food
mg/kg (milligrams per kilogram) is equivalent to g/g (micrograms per gram) and ppm (parts per million).
g/kg (micrograms per kilogram) is equivalent to ng/g (nanograms per gram) and ppb (parts per billion).
Standards for shellfish toxins, glycoalkaloids, and histamines are sometimes expressed as mg/100 g or g/100 g; to convert a standard in mg/kg to mg/100 g, divide the value by 10 (e.g. 200 mg/kg = 20 mg/100 g); to convert a standard in mg/kg to g/100 g, multiply the value by 100 (e.g. 0.8 mg/kg = 80 g/100 g).
Amnesic Shellfish Poisoning toxin (ASP) (Domoic acid) 20 mg/kg In bivalve shellfish edible tissue
Deoxynivalenol (Vomitoxin) 2.0 mg/kg
(under review)
In uncleaned soft wheat for use in non-staple foods
1.0 mg/kg
(under review)
In uncleaned soft wheat for use in baby foods
Diarrhetic Shellfish Poisoning toxins (DSP)
(sum of okadaic acid and dinophysis toxins (DTX-1, DTX-2 and DTX-3))
1 mg/kg
(under review)
In bivalve shellfish digestive tissue
0.2 mg/kg
(under review)
In bivalve shellfish edible tissue
Ethyl carbamate 30 µg/kg In table wines
100 µg/kg In fortified wines
150 µg/kg In distilled spirits
400 µg/kg In fruit brandies and liqueurs
200 µg/kg In sake
Glycoalkaloids, total (sum of alpha-solanine and alpha-chaconine) 200 mg/kg In potato tubers (fresh weight)
Histamines 200 mg/kg In anchovies, fermented fish sauces and pastes
100 mg/kg In other fish and fish products
3-MCPD
(3-monochloropropane-1,2-diol)
1 mg/kg In Asian-style sauces such as soy, oyster, mushroom sauces, etc.
Melamine 0.5 mg/kg
(combined concentration of melamine and cyanuric acid)
(interim standard)
In infant formula and sole source nutrition products, including meal replacement products
2.5 mg/kg
(combined concentration of melamine and cyanuric acid)
(interim standard)
In food products containing milk and milk-derived ingredients, except infant formula and sole source nutrition products, including meal replacement products

Mercury

0.5 mg/kg 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 mg/kg 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"]
Patulin 50 g/kg In apple juice, including the apple juice portion of any juice blends or drinks, and unfermented apple cider
PAHs
(polycyclic aromatic hydrocarbons)
3 µg/kg 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
Paralytic Shellfish Poisoning toxins (PSP)(saxitoxin equivalents) 0.8 mg/kg In bivalve shellfish edible tissue
Pectenotoxins (PTX) (sum of PTX-1, PTX-2, PTX-3, PTX-4, PTX-6 and PTX-11) 1 mg/kg In bivalve shellfish digestive tissue

0.2 mg/kg

In bivalve shellfish edible   tissue