RESPONSE OF LISTERIA-MONOCYTOGENES AND VIBRIO-PARAHAEMOLYTICUS TO HIGH HYDROSTATIC-PRESSURE

Listeria monocytogenes Scott A and CA, were subjected at 23-degrees-C to hydrostatic pressures ranging from 2,380 to 3,400 atm and Vibrio parahaemolyticus T-3765-1 from 680 to 1,700 atm. For L. monocytogenes Scott A, pressurization in ultra-high temperature-processed (UHT) milk and raw milk appeared to provide a protective effect and lessened cell death as compared to pressurization in phosphate-buffered saline (100 mM, pH 7.0). A population of about 10(6) CFU/mL L. monocytogenes was killed by exposure to 3,400 atm within 80 min at 23-degrees-C in UHT milk. A population of about 10(6) CFU/mL V. parahaemolyticus was killed by exposure to 1,700 atm within 10 min at 23-degrees-C in clam juice.