Thermotolerance of heat-shocked Listeria monocytogenes in milk exposed to high-temperature, short-time pasteurization.
The effect of prior heat shock (48 degrees C for 15 min) on the thermotolerance of Listeria monocytogenes at the minimal high-temperature, short-time (71.7 degrees C for 15 s) parameters required by the Pasteurized Milk Ordinance was examined. The mean D71.7 degrees C value for heat-shocked L. monocytogenes was 4.6 +/- 0.5 s (control D = 3.0 +/- 1.0 s); the ratio of D to control D was 1.5. The increased thermotolerance of heat-shocked Listeria cells was not significant and appeared unlikely to have practical implications, in terms of risk assessment, for the safety of pasteurized milk.
Bunning
V K
VK
Division of Microbiology, Food and Drug Administration, Laurel, Maryland 20708.
Crawford
R G
RG
Tierney
J T
JT
Peeler
J T
JT
D000818:Animals; D005516:Food Microbiology; D006358:Hot Temperature; D008089:Listeria monocytogenes / Q000254:growth & development* / Q000302:isolation & purification; D008892:Milk / Q000382:microbiology*; D013242:Sterilization / Q000379:methods*; D013997:Time Factors