cell suspensions of Listeria monocytogenes 5366,staphylococcus aureus 976 and pseudomonas aeruginosa 110T were exposed to high pressure treatment from 200 to 600 Mpa for 5,10 and 15 min at an initial temperature of 20°C in raw skimmed bovine milk,whey an phosphate buffer, PH 7.0 in order to determine their degree of inactivation.