The British government is to undertake a nationwide survey into milk quality in the wake of fears that a harmful bacteria affecting cattle could be causing Crohn's disease, it was announced last night.
The survey, being undertaken by the Ministry of Agriculture, Fisheries and Food, will include all main types of milk, with over a thousand samples being examined for a range of bacteria. The investigation will be carried out by Queen's University, Belfast and the Agriculture Development Advisory Service.
At the request of the Advisory Committee for the Microbiological Safety of Food, the samples of milk will be assessed for the presence of mycobacterium paratuberculosis. The bacteria is the cause of Johne's disease, a disorder of cattle across the world.
It is one of several factors that have been suggested as a possible cause of Crohn's disease, a chronic inflammation affecting the intestine in humans.
Previous research indicated that pasteurisation should be effective in destroying the organism.
But provisional, unconfirmed results from a small number of samples analysed as part of the preparatory work showed that the bacteria may be present in pasteurised milk, albeit to a lesser extent than in raw milk.
The British Department of Health stressed that on the basis of what is currently known about the bacteria, there is no need for anyone to change their dietary habits. Symptoms of Crohn's disease, which is difficult for doctors to diagnose, include severe stomach cramps, sickness and diarrhoea. Some cases lead to tumours in the bowel and intestines.
The National Farmers Union said it fully supported the survey. "We support any research that gives strength to the argument that milk is a nutritious and wholesome product," a spokeswoman said.
Sixteen dairies in Northern Ireland were visited as part of the preparatory work for the survey.
In total 62 samples were collected, 31 of raw milk and 31 of pasteurised milk.
Dr Norman Simmons, a government food safety adviser, last night played down the risk. "At best, there is no risk at all. At worst, if those people who think it's capable of causing human disease are correct, at worst I have calculated myself that the risk is about one in five million if you drink a glass of milk," he told ITN's News at Ten.
The National Dairy Council said it was "surprised" at the preliminary research results.
A spokeswoman said: "Pasteurisation is a food safety process used throughout the world which has been tried and tested for over 50 years and is subject to many strictly enforced controls.