The contaminant, acrylamide, is formed when certain foods, particularly plant-based foods rich in carbohydrates and low in protein, are cooked at temperatures higher than 120 degrees Celsius, and the Food and Agricultural Organization (FAO) and World Health Organization (WHO) called for preparation technologies that significantly lower the acrylamide level.

Preliminary investigations by industry and other researchers seem to suggest that significant reductions are currently feasible in several foods, the agencies added in releasing a joint report by a committee of 35 experts from 15 countries.

The neurotoxicity of acrylamide in humans is known from instances of high occupational and accidental exposure when the contaminant is used in industrial processes in the production of plastics and other materials. Studies in animals have shown that it caused reproductive problems and cancer.

The Joint FAO/WHO Expert Committee on Food Additives and Contaminants (JECFA), meeting last month to consider the possible risks of acrylamide and five other food contaminants, concluded that on the basis of the tests in animals cancer was the most important toxic effect of acrylamide and consumption of foods with it at current levels of occurrence may be a public health concern.

The conclusion was based on a conservative evaluation, according to the committee, which noted that there is still considerable uncertainty about the mechanism of the toxicity of acrylamide, assumptions used to compare the most relevant animal data to the human situation, and extrapolation of the intake assessments.

The amount of acrylamide can vary dramatically in the same foods depending on several factors, including cooking temperature and time. Because of this, JECFA experts said that it was not possible to issue recommendations on how much of any specific food containing the substance is safe to eat.

JECFA noted that the food industry is evaluating means to reduce acrylamide levels in various foods and recommended that these efforts continue. The experts also cautioned that major changes in food processing methods to reduce acrylamide would need to be checked for nutritional quality and safety, including microbiological contamination, and the possible formation of other undesirable chemicals. Consumer acceptability also has to be considered.

The latest information on acrylamide reinforces general advice on healthy eating and consumers should continue to eat balanced and varied diets, which include plenty of fruit and vegetables, and to moderate their consumption of fried and fatty foods, the agencies said.