ARCHIVED - World Health Organization (WHO) Expert Meeting to Review Toxicological Aspects of Melamine and Cyanuric Acid

The WHO Collaborating Centre for Food Contamination Monitoring within Health Canada's Food Directorate supported the organization of the World Health Organization's expert meeting to review toxicological aspects of melamine, cyanuric acid and related analogues. This meeting was held in collaboration with the Food and Agriculture Organization of the United Nations (FAO) and took place December 1-4, 2008 in Ottawa, Ontario, Canada.

Meeting Objectives and Outcome

Objectives:

To review of current knowledge on:

  • Chemistry of melamine alone and in combination with its analogues (e.g. cyanuric acid)
  • Analytical methods relative to detection of these chemical substances in various foods
  • Occurrence of melamine in foods as a result of normal food production and processing (e.g. migration from food contact materials, pesticide or fertilizer use) as opposed to adulteration
  • Toxicity of melamine alone and in combination with its analogues (e.g. cyanuric acid)
  • Human health risk assessment, including species sensitivities and sensitive sub-populations
  • Knowledge gaps

The outcomes of the expert meeting included a description and analysis of the following areas:

  • Current state of knowledge on toxicology, exposure and analytical methodology
  • Risk assessment, including attendant uncertainties
  • Knowledge gaps
  • Conclusions and recommendations

Health Canada contributed food surveillance information from Canada on melamine for use in the WHO expert meeting. This information was generated as a response to the 2008 melamine incidents in China and was subsequently used, not only by Health Canada for risk assessment purposes, but also by scientists attending the Expert Meeting.

As a result of this Expert Meeting, Health Canada adopted the WHO recommended Tolerable Daily Intake (TDI) for melamine in foods of 0.2 mg/kg body weight per day. As an additional measure, due to the various forms in which infant formula is available on the Canadian market (i.e., liquid ready-to-consume, concentrated and powdered), the maximum allowable limit for melamine in infant formulas and other sole source nutrition products was lowered from 1 ppm to 0.5 ppm in order to ensure that any exposures resulting from these types of products remain below the WHO TDI. It is important to note that all infant formula products tested on the Canadian retail market were well below the 0.5 ppm maximum limit.

Aside from one  sample of imported candy recalled in 2008, the products tested through Health Canada's surveillance of food fell well within Health Canada's maximum limits for melamine in products containing milk and milk-derived ingredients, and have been deemed not to pose a health risk for consumers.

Since that time, Health Canada has published its research on the background levels of melamine found in certain foods, including the data that was shared with the WHO Expert Meeting in 2008. Health Canada's research continues to show that the low background levels of melamine that can sometimes be found in food are not a risk to the health of Canadians.

Sheryl A. Tittlemier, Benjamin P.-Y. Lau, Cathie Me´nard, Catherine Corrigan, Melissa Sparling, Dean Gaertner, Xu-Liang Cao and Bob Dabeka. Baseline levels of melamine in food items sold in Canada. I. Dairy products and soy-based dairy replacement products. Food Additives and Contaminants: Part B. Vol. 3, No. 3, September 2010, 135-139.

 Sheryl A. Tittlemier, Benjamin P.-Y. Lau, Cathie Me´nard, Catherine Corrigan, Melissa Sparling, Dean Gaertner, Xu-Liang Cao, Bob Dabeka and Carla Hilts.  Baseline levels of melamine in food items sold in Canada. II. Egg, soy, vegetable, fish and shrimp products. Food Additives and Contaminants: Part B. Vol. 3, No. 3, September 2010, 140-147.

More information on the  WHO Expert Meeting

New guidance to help improve food safety provided by UN food standards commission

Beginning in 2009, Health Canada shared its scientific research, as well as having designating its ressources to assist the United Nations' food standards body, Codex Alimentarius Commission, in the development of new guidance to help improve food safety by limiting melamine levels in powdered infant formula to 1 mg/kg, as well as limiting levels in other foods and animal feed to 2.5 mg/kg. This guidance was adopted on July 6, 2010. Differences between the  levels proposed by Codex and those adopted by Health Canada are explained by Health Canada's adopted tolerable daily intake being specific to milk-derived products only.

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