ARS | Publication request: HEAT INACTIVATION OF MYCOBACTERIUM PARATUBERCULOSIS IN RAW MILK USING HOLDER-TEST TUBE METHOD AND LAB-SCALE INDUSTRIAL PASTEURIZATION METHOD

Submitted to: United States Animal Health Association Proceedings
Publication Type: Proceedings
Publication Acceptance Date: October 12, 1996
Publication Date: N/A

Technical Abstract: Recent evidence has linked Crohn's disease, an inflammatory enteritis, in humans to infection with M. paratuberculosis (paraTb). One possible source of human exposure to M. paraTb is the consumption of milk or dairy products, since presence of paraTb DNA has been documented in cow's milk obtained from retail markets in Great Britain. Evaluation of optimal time/temperature combinations for effective heat inactivation of M. paraTb was determined using either a holder-test tube method or a lab-scale industrial pasteurization method. Raw milk was inoculated with M. paraTb, heated, and aliquots were removed for serial dilution and culture on HEYM. Results from the holder-test tube method indicate that the most effective reduction in viable bacterial numbers was achieved at 72C, but mean time for optimal killing superceded industry recommendations of 15 seconds at that temperature. Studies with the lab-scale pasteurizer demonstrated that treatment at 72C for 15 seconds effectively killed all the bacteria. Comparison of these two models for testing heat inactivation of M. paraTb indicate that the lab-scale pasteurizer more closely simulates industry conditions and that results from those experiments should be given more careful consideration.