Review of the controversy over whether or not Mycobacterium avium subsp. paratuberculosis poses a food safety risk with pasteurised dairy products

There is no question that Mycobacterium avium subspecies paratuberculosis (MAP) causes Johne's disease, a slow-advancing, chronic and fatal disease in cattle and other ruminants. However, in relation to human disease, specifically Crohn's disease (CD), the involvement of MAP is controversial and hotly debated. Whilst most studies have targeted milk as a vector in regard to the exposure of humans to MAP via food, potential sources of MAP in the human food chain are manifold and include meat, water and vegetables. With milk products, the effectiveness of pasteurisation has also been disputed, with the impact of experimental design coming under scrutiny. This critical review shows that evidence implicating MAP as the causative agent of CD is lacking. Further, it determines that the weight of evidence indicates that commercial pasteurisation of milk inactivates MAP and concludes that the evidence that MAP poses a food safety risk for pasteurised dairy products is not robust.