Inactivation of Mycobacterium paratuberculosis by pulsed electric fields.
The influence of treatment temperature and pulsed electric fields (PEF) on the viability of Mycobacterium paratuberculosis cells suspended in 0.1% (wt/vol) peptone water and in sterilized cow's milk was assessed by direct viable counts and by transmission electron microscopy (TEM). PEF treatment at 50 degrees C (2,500 pulses at 30 kV/cm) reduced the level of viable M. paratuberculosis cells by approximately 5.3 and 5.9 log(10) CFU/ml in 0.1% peptone water and in cow's milk, respectively, while PEF treatment of M. paratuberculosis at lower temperatures resulted in less lethality. Heating alone at 50 degrees C for 25 min or at 72 degrees C for 25 s (extended high-temperature, short-time pasteurization) resulted in reductions of M. paratuberculosis of approximately 0.01 and 2.4 log(10) CFU/ml, respectively. TEM studies revealed that exposure to PEF treatment resulted in substantial damage at the cellular level to M. paratuberculosis.
Rowan
N J
NJ
Department of Bioscience and Biotechnology, University of Strathclyde, Glasgow, Scotland. n.j.rowan@strath.ac.uk
MacGregor
S J
SJ
Anderson
J G
JG
Cameron
D
D
Farish
O
O
D000818:Animals; D003424:Crohn Disease / Q000209:etiology; D004560:Electricity; D005511:Food Handling / Q000379:methods*; D006358:Hot Temperature; D008892:Milk / Q000382:microbiology*; D016927:Mycobacterium avium subsp. paratuberculosis / Q000648:ultrastructure; D010283:Paratuberculosis