Heat resistance of Mycobacterium avium ssp paratuberculosis in raw milk tested in a pilot plant pasteurizer

Mycobacterium avium ssp. paratuberculosis (M. paratuberculosis) is the causative agent of Johne's disease of cattle. Under discussion is this organism as one causative factor in Crohn's disease of humans. Similarities of clinical symptoms and pathological findings in animal and man but also microbiological and molecular findings in patients led to this hypothesis. Based on several reports on a possible resistance of M. paratuberculosis to pasteurization temperatures, pasteurized milk is frequently considered as a potential vehicle for transmission of the disease. Heating experiments reported in the literature show differing results about the inactivation of M. paratuberculosis in milk. In order to reflect practical situations, a heating technology as comparable as possible to commercial systems was applied. Various time-temperature combinations were examined in heating experiments over a three year period and are reported in this study.