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The World Health Organization has considered possible public health concerns with regard to semicarbazide (SEM) in food at the request of several Member States and based on information provided by the European Food Safety Authority (EFSA). These concerns arise from the presence of SEM in food products packaged in glass jars with metal lids that have foamed plastic seals. SEM has been detected at low levels in a number of such food products, including baby foods. The origin of SEM in these cases has been linked to the permitted use of azodicarbonamide in the plastic seals. The presence of SEM has raised concern since it has weak carcinogenic activity when fed to laboratory animals at high doses. Based on levels reported in food, the health risk, if any, to consumers, including infants, appears to be very small. However, since the relatively high consumption of products in glass jars by infants can result in higher exposure as compared to other consumers, the presence of SEM in baby foods is considered particularly undesirable. Therefore, WHO recommends, that as a priority, alternative materials be evaluated for their suitability, including their microbiological and chemical safety and introduced as rapidly as possible for baby foods, and subsequently other foods.

WHO notes that other possible sources of dietary exposure to SEM should be investigated. For example, SEM is a known metabolite of the veterinary drug nitrofurazone and is used as an indicator for the use of the drug in food of animal origin. SEM has also been detected in seaweed derived products, which are widely used as food additives. Azodicarbonamide, in addition to its use in foamed seals, is used as a blowing agent in rubber products and foamed polyethylenes that are permitted for other food packaging applications. In a number of countries, azodicarbonamide is also approved as a food additive for use as a bleaching agent in cereal flour and as a dough conditioner. Azodicarbonamide was reviewed in 1965 by the Joint FAO/WHO Committee on Food Additives (JECFA), which recommended a maximum treatment level for flour of 45 mg/kg. Azodicarbonamide is also used in certain pesticide formulations and industrial applications.

Further studies aimed at clarifying whether SEM is formed from azodicarbonamide are needed. In addition, better information on the mechanism of toxicity and on exposure to SEM from all sources would help to define the nature of what is now considered to be a low risk to human health. The International Programme on Chemical Safety (IPCS) reviewed the human health concerns for azodicarbonamide primarily from the perspective of occupational exposure in 1999.

WHO will continue to monitor the situation with regard to SEM in food. If sufficient additional information so warrants, WHO, in collaboration with the Food and Agriculture Organization of the United Nations (FAO), will carry out risk assessments of SEM and possibly azodicarbonamide to provide sound scientific advice to the Codex Alimentarius Commission and Member States. Related to this issue, the potential linkage of azodicarbonamide, SEM and ethyl carbamate, another chemical of concern, needs to be elucidated. JECFA is planning to conduct a risk assessment of ethyl carbamate at its 64th Meeting in February 2005.

Call for data

In order to facilitate the decision to carry out additional risk assessments, WHO requests that existing data and notices of planned studies for both SEM and azodicarbonamide be provide on toxicity and on human exposure, including occurrence, levels, formation and fate. Information from national and regional risk assessments is especially sought. Data on levels of SEM and azodicarbonamide in food and the diet should be electronically submitted using the GEMS/Food format.

All data and notices of planned studies should be submitted to:

Dr Angelika Tritscher
World Health Organization
WHO Joint Secretary to JECFA
Avenue Appia 20
1211 Geneva 27, Switzerland
Telephone: (+41 22) 791 35 69
Fascimile: (+41 22) 791 48 48

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