A European team of scientists has established the source of semicarbazide contamination in jars of food.

Richard Stadler of the Nestlé Research Centre in Lausanne, Switzerland, and his colleagues claim that it is a minor thermal decomposition product of azodicarbonamide (ADC), a blowing agent used in the manufacture of the PVC seals that ensure a tight fit between the jar and the lid.

There is evidence from animal studies that semicarbazide is a weak carcinogen but, because of the limited evidence, it is not possible to conclude whether or not semicarbazide may pose a cancer risk to humans.

Sir John Krebs, Chair of the UK Food Standards Agency comments: 'We have made it clear to the European Commission and the food industry that alternative methods for sealing jars should be developed as a precautionary measure'.

Ian Farrell