RG-8 Regulatory Guidance:
Contaminants in Feed (formerly RG-1, Chapter 7)

Section 4: Metal Contaminants

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The CFIA regularly monitors foods and livestock feeds for contaminants which have the potential to impact the safety of the food chain and the health of animals. Livestock feeds and feed ingredients are monitored for the presence of metal contaminants because these contaminants may be harmful to livestock and humans.

Metals are elemental chemicals found naturally, to varying degrees, in the environment, feeds, and foods. They are also used in many industrial processes, including feed ingredient manufacture. In their elemental state, metals cannot be metabolised or destroyed; therefore, livestock that consume metal-contaminated feeds could accumulate these contaminants in their tissues over time. Contaminated animals could then transfer the metal to their offspring, the animal feed chain, the environment, or to foods of animal origin. Even trace amounts of certain metal contaminants may result in unacceptable tissue residues in foods for human consumption (e.g., meat, milk or eggs). Furthermore, feeds with high metal loads pose a human health hazard to those individuals working with, or otherwise exposed to, the product.

Sampling

All feed types can be sampled for metal contamination as part of the National Feed Inspection Program. This involves random sampling of a variety of feed products, including complete feeds and feed ingredients. The focus has been on sampling mineral ingredients, premixes and mineral supplements, because metal contaminants are more likely to originate from these feed ingredients. Samples are randomly taken by feed inspectors at commercial feed mills, rendering plants, retailers of livestock feeds, and on farms.

Metal contaminants of concern and Action Levels

Metal contaminant residues of concern which are routinely analysed include aluminum (Al), arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb) and mercury (Hg). Mercury is only monitored in fish by-products (i.e., fish meal, fish oil). Action Levels have been defined for aluminum, arsenic, cadmium and lead (See Table 5) and enforced by the Animal Feed Division for a number of years. Action levels have not been established for chromium and mercury; however, sample results for chromium and mercury are assessed on a case-by-case basis.

A feed Action Level is the level at which, if exceeded, a metal contaminant may present a health risk, due to the potential for metal toxicity or due to unacceptable residues in foods of animal origin. These levels were established to assist with product safety assessments (i.e., identification of possible sources of contamination and appropriate corrective actions); and to facilitate industry compliance. These levels are based on the total livestock diet and not based on individual minerals.

Table 5: Action Levels for metal contaminants in total livestock diets on an "as fed" basis, including feeds and forages.
Metal Contaminant Action LevelTable note 4 Reporting Limit/
Limit of Quantification
Aluminum (Al) non-ruminant: 200 ppm

ruminant: 1,000 ppm

3.2 ppm
Arsenic (As) ppm 5.2 ppm
Cadmium (Cd) horses: 0.2 ppm

other livestock: 0.4 ppm

0.05 ppm
Lead (Pb) ppm ppm

Table note

Table note 4

Equals the maximum level for the metal contaminant in total livestock diets.

Return to table note 4 referrer

Compliance and Calculations of Interest

A product sampled for metal contaminants is considered acceptable if the metal contaminant is found at a level below the Action Level. The Action Level is set for total diets, therefore, in cases where the product is not a total diet (i.e., where it needs to be mixed with another feed, diluted, or mixed with forage), calculations must be done to determine the concentration of the metal in the total diet. If the ingredient may be added to multi-species feeds, then the highest suggested inclusion rate should be considered as the worst-case scenario.

Example calculation – acceptable:
Monogastrics (swine, poultry) Horses and ruminants (cattle, sheep, goats)
Lab result for Cadmium (Cd) in a premix: 3.6 ppm 3.6 ppm
Inclusion rate of premix in complete feed: 5% 5%
Inclusion rate in total diet (50% forage): n/a 50%
Level of Cd in total diet: 0.18 ppm
(= 3.60×0.05)
0.09 ppm
(= 3.60×0.05×0.5)

Decision: the calculated level of Cd for monogastric, horse, and ruminant diets is below the Action Level for Cd for horses (0.2 ppm) as well as all other livestock species (0.4 ppm), so this product is acceptable.

Example calculation – not acceptable:
Monogastrics (swine, poultry) Horses and ruminants (cattle, sheep, goats)
Lab result for Cadmium (Cd) in a premix: 15.0 ppm 15.0 ppm
Inclusion rate of premix in complete feed: 5% 5%
Inclusion rate in total diet (50% forage): n/a 50%
Level of Cd in total diet: 0.75 ppm
(= 15.00×0.05)
0.38 ppm
(= 15.00×0.05×0.5)

Decision: the calculated level of Cd for both monogastric and horse diets exceeds their Action Levels for Cd (0.4 ppm and 0.2 ppm respectively), so this product is not acceptable for monogastrics or horses. However, the calculated level of Cd for ruminant diets is below the Action Level for Cd (0.4 ppm), so this product is acceptable for ruminants.

Feeds that exceed the Action Level for any metal should not be fed to livestock. This approach facilitates the identification and elimination of contaminant sources in human foods and livestock feeds.

Feed manufacturers and producers are reminded of their responsibility to source ingredients from suppliers who have demonstrable records/systems in place to ensure ingredient safety. This will help promote the production of feeds that:

  1. are safe for all classes of livestock, and
  2. will not result in harmful tissue residues in livestock or animal products destined for human consumption.
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