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The fate of Bacillus anthracis in unpasteurized and pasteurized milk
Author(s) -
Bowen J.E.,
Turnbull P.C.B.
Publication year - 1992
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 - 10.1111/j.1472-765x.1992.tb00769.x
Subject(s) - pasteurization , bacillus anthracis , spore , bacillus cereus , cereus , food science , bacillales , inoculation , biology , microbiology and biotechnology , bacteria , horticulture , genetics , bacillus subtilis
Events following the inoculation of vegetative and spore forms of Bacillus anthracis into unpasteurized and pasteurized milk were monitored at 37 ° C, room temperature (RT; 20 × 2 ° C) and in a refrigerator (5–9 ° C). Counts of vegetative B. anthracis decreased rapidly in both unpasteurized and pasteurized milk, becoming unde‐tectable by 7 h at 37 ° C and by 24 h at RT and in the refrigerator. Spores in unpasteurized milk showed no significant signs of germination after 48 h. In pasteurized milk, there was a slight overall increase (1 log) in total and spore counts at 37 ° C; at RT there was an overall fall (1.5‐2 logs) and in the refrigerator, total counts remained steady while spore counts fell 1 log over a 48 h period. The frequently observed rise in counts of endogenous (presumptively identified) B. cereus from undetectable to >10 6 /ml at 37 ° C and > 10 5 /ml at RT by 24 h contrasted with the behaviour exhibited by the vegetative B. anthracis.