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Effect of high‐temperature, short‐time (HTST) pasteurization on milk containing low numbers of Mycobacterium paratuberculosis
Author(s) -
Irene R. Grant,
Rowe
Publication year - 1998
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1046/j.1472-765x.1998.00309.x
Subject(s) - paratuberculosis , pasteurization , raw milk , food science , mycobacterium avium subsp. paratuberculosis , chemistry , mycobacterium , microbiology and biotechnology , biology , bacteria , genetics
The efficacy of high‐temperature, short‐time (HTST) pasteurization (72 °C/15 s) when low numbers (≤ 10 3 cfu ml −1 ) of Mycobacterium paratuberculosis are present in milk was investigated. Raw cows’ milk spiked with Myco. paratuberculosis (10 3 cfu ml −1 , 10 2 cfu ml −1 , 10 cfu ml −1 , and 10 cfu 50 ml −1 ) was subjected to HTST pasteurization using laboratory pasteurizing units. Ten bovine strains of Myco. paratuberculosis were tested in triplicate. Culture in BACTEC Middlebrook 12B radiometric medium detected acid‐fast survivors in 14·8% and 10% of HTST‐pasteurized milk samples at the 10 3 and 10 2 cfu ml −1 inoculum levels, respectively, whereas conventional culture on Herrold’s egg yolk medium containing mycobactin J detected acid‐fast survivors in only 3·7% and 6·7% of the same milk samples. IS900‐based PCR confirmed that these acid‐fast survivors were Myco. paratuberculosis . No viable Myco. paratuberculosis were isolated from HTST‐pasteurized milk initially containing either 10 cfu ml −1 or 10 cfu 50 ml −1 .