The government is launching a nationwide survey into milk quality following fears that it could be carrying a bacteria causing bowel disease. Experts from the Ministry of Agriculture, Fisheries and Food will investigate all types of milk for the bacteria mycobacterium paratuberculosis.
The bacteria causes Johne's disease, a disorder of cattle across the world.
But it is one of several factors that have been suggested as causing Crohn's Disease, a chronic inflammation affecting the intestine in humans.
Previous research suggested that pasteurisation should destroy the organism.