Every chicken may have to be frozen or steamed The bacteria, which make 280,000 people ill every year and can result in death, are present on the skin of 70 per cent of chickens, according to the Food Standards Agency. It has told Tesco, Morrisons, Sainsbury's, Co-op, M&S, Waitrose and Asda to reduce the figure to 10 per cent by the end of next year. In response, supermarkets are considering freezing the skin of the chickens or steaming it to kill surface bacteria. Steaming cooks the outside of the skin, eliminating most of the campylobacter, but leaves chickens an "anaemic" off-white colour. The freezing procedure involves spraying poultry with liquid nitrogen. Exposing the birds to temperatures below 35.6F (2C) would force supermarkets to classify them as frozen, even though the inside would remain uncooked. All the main supermarket chains are running trials on at least one of the options. Asda has said that if trials of a heating technique called Sonosteam prove effective, it would ask all its suppliers to use the process.