§ Mr. CryerTo ask the Minister of Agriculture, Fisheries and Food if he will publish the evidence for non-pasteurised milk becoming prone to infection with listeria bacteria; and if he will make a statement.
§ Mr. Ryder[holding answer 21 February 1989]: The results of a number of overseas surveys published in the scientific literature indicate that about 10 per cent. of raw milk may be infected with listeria species. It is possible that similar rates of infection exist in the United Kingdom milk supplies. Pasteurisation has however been shown to be an effective treatment for eliminating listeria and other more prevalent pathogens, such as salmonella and campylobacter.
Information from the communicable disease surveillance centre on the 1,600 cases of food poisoning associated with untreated milk in the five-year period 1983–87 indicates that the main health hazard associated with untreated milk is not listeria but salmonella (which accounted for just over half the cases) and campylobacter (which accounted for most of the remainder).