As a sufferer from Crohn's disease you may be concerned following the recent publication in the national press implicating mycobacterium paratuberculosis as a cause of the disease.
The organism is known to cause a similar disease in animals, (Johne's disease) and for many years workers have been trying to link it to the development of Crohn's disease in humans, with varying degrees of success.
Professor Hermon Taylor and his colleagues at St George's Hospital in London reported to have found mycobacterium paratuberculosis in about 65% of their Crohn's disease patients. Tissue samples were taken from operation specimens and DNA isolated using sensitive testing methods. However, Rowbotham and his colleagues at St James's Hospital in Leeds were unable to reproduce these positive results despite using the same testing methods and other more specific and sensitive methods. the reasons for the positive findings were thought to be due to laboratory contaminants or other artefacts of testing.
The organism can occur in milk supplies (unpasteurised), tap water and soil and it is likely that mycobacterium paratuberculosis is a secondary invader which may influence histological changes but is not the primary cause of the disease.
For a disease to be infectious it must satisfy the four postulates of the great bacteriologist Robert Koch, i.e.
1. The organism must be present in all cases of the disease
Professor Taylor was only able to find the organism in 65% of his patients; other workers were unable to isolate a single organism except in one non-Crohn's patient. Therefore these postulates are not satisfied.
It is extremely rare for Crohn's disease to occur in the spouse of a patients. First degree relatives not living together have a very much higher incidence of the disease, suggesting a genetic, rather than infectious link.
Lastly, treatment with anti-tubercular therapy is ineffective in the treatment of Crohn's disease.
Although gastroenterologists may talk about bacteria being a possible cause of the disease, this is not due to infection, but rather to the process of abnormal fermentation of food residues in the large intestine. Chemicals are produced from this process which may damage the lining of the intestines causing inflammation, ulceration and bleeding.
It is possible that you may be intolerant to the protein or sugar in milk which can lead to the development of the disease when these products are fermented and not due to the fact that the milk could be contaminated with mycobacterium paratuberculosis.
If you have further concerns or doubts about the safety of milk you could always switch to ultra heat treated milk (UHT) or discuss the matter further with the doctor.