25 January 2000
‘Crohn’s bug lives in pasteurised milk’
By FWi staff
PASTEURISED milk is harbouring a germ which causes a debilitating disease which affects thousands, a leading medical scientist has claimed.
John Prof Hermon-Taylor, head of the surgical department at St Georges medical school in London, claims that a bacterium mycobacterium avium subspecies paratuberculosis (MAP) survives pasteurisation.
MAP is thought to cause the inflammatory bowel disorder Crohns Disease, which effects 80,000 people in Britain.
Although not a killer, Crohns disease debilitates and affects ability to ward of other diseases
“In Western Europe and North America between 21 and 54% of dairy herds are sub-clinically infected with this bug called MAP,” Prof Hermon-Taylor told the Radio 4 Farming Today programme.
He said animals secrete the organism in their milk and on to their pastures, where it survives, as it is much tougher than its close relative tuberculosis.
“It is not completely inactivated by pasteurisation at current levels,” he warned.
“The chances that MAP is reaching human populations in retail pasteurised milk are very, very high
“Humans are, Im afraid to say, drinking it down in retail pasteurised milk.”
But Prof Hermon-Taylor said moves by the National Dairy Council to increase the pasteurisation time would go some way to reducing the risk.
While in the past milk was heated for 15 seconds at 72°C, it is now heated at the same temperature for 25 seconds.
Although this may not kill the bug, Prof Hermon-Taylor said it would almost certainly render it unable to multiply.
“Within the limits of the test applied, this is a big step in the right direction.”
He advised farmers separating cows from calves early on to be careful not to feed them on milk from infected animals, and to ensure slurry did not lie around the farm.
In addition to preventive measures, Prof Hermon-Taylor wants the disease to be made notifiable, which will require wide-ranging testing for MAP in dairy herds and the water supply.