Bacteria survives milk processing

A bacteria found in cows has been found in milk

A bacteria suspected of causing or contributing to Crohn's disease has been found in pasteurised milk samples.

The direct link between the disabling gut condition and the paratuberculosis bacterium has yet to be proven.

But the discovery, by Ministry of Agriculture-funded scientists, that the bug has the ability to survive milk processing will increase calls for further research into the issue.

Crohn's disease causes chronic inflammation of the bowel, and affects between 40,000 and 60,000 people in the UK.

The Belfast-based research team tested pasteurised and unpasteurised milk - and their preliminary results were that bacteria were present in 3% of samples.

The controversy over paratuberculosis - often called MAP - and milk erupted in 1998.

Lengthened pasteurisation

Milk producers agreed to lengthen the pasteurisation process from 15 seconds to 25 seconds to increase the chances that the microbe would be eradicated.

It is not confirmed whether the latest results involved pasteurisation for 15 or 25 seconds.

The theory that MAP can cause or worsen Crohn's disease has been championed by Professor Hermon-Taylor.

He says studies have found traces of the bacteria in the bowel lining of patients with Crohn's.

"Seven out of 10 studies looking at this problem, using the latest genetic fingerprinting techniques, find a significant association between the MAP strain found in cattle and Crohn's disease."

He said that the bacteria - thought to be present in many dairy herds - was behind a cattle disease called Johnes disease - which also causes chronic bowel inflammation.

However, Richard Driscoll, director of the the National Association for Crohn's and Colitis, said that the link between the bacteria and the illness was not yet fully proven, despite all the evidence.

However, he said that the new evidence about pasteurised milk meant further research was needed.

"It will cause MAFF to review their pasteurisation strategy when they have the complete results.

"If people have Crohn's and are concerned, one thing they can do is switch to UHT milk, on the assumption that there is less chance of there being any bacteria."