Barotolerance of Staphylococcus aureus is increased by incubation at below 0 °C prior to hydrostatic pressure treatment

The effect of preincubation under low temperatures on inactivation of Staphylococcus aureus IFO 13276 by hydrostatic pressure treatment (HPT) was investigated. Preincubation before HPT was carried out by submerging cell suspension in an ethylene glycol bath at temperatures from 30 to −20 °C for 15 min. After HPT at the same temperatures, survivors of incubated S. aureus was not significantly (P>0.05) influenced when preincubation took place at temperatures above 0 °C. Survivors of incubated S. aureus, however, were approximately two log cycles higher when preincubation took place at temperatures below 0 °C. This increase in barotolerance of S. aureus was not observed in the presence of 40 μg/ml of chloramphenicol.