Effect of combinations of high-pressure treatment and bacteriocin-producing lactic acid bacteria on the survival of Listeria monocytogenes in raw milk cheese

The combined effect of high-pressure (HP) treatment and bacteriocin-producing lactic acid bacteria (BP-LAB) on the survival of Listeria monocytogenes Scott A in cheeses made from raw milk that was inoculated with the pathogen at 4.80 log cfu mL−1, a commercial starter and one of seven strains of BP-LAB was investigated. On day 3, the counts of L. monocytogenes were 7.03 log cfu g−1 in a control cheese (without BP-LAB, not HP treated), 6.06-6.74 log cfu g−1 in cheeses with BP-LAB, 6.13 log cfu g−1 in a cheese without BP-LAB and treated on day 2 at 300 MPa, 2.01 log cfu g−1 in a cheese without BP-LAB and treated on day 2 at 500 MPa, 3.83-5.43 log cfu g−1 in cheeses with BP-LAB and treated on day 2 at 300 MPa, and 1.81 log cfu g−1 or less in cheeses with BP-LAB and treated on day 2 at 500 MPa. HP treatment was more effective on day 51 than on day 2.