Combined use of bacteriocin-producing strains to control Listeria monocytogenes regrowth in raw pork meat

P>Avoiding the presence of Listeria in meat and dairy products is a major challenge for the food industry. In this work, a Lactobacillus curvatus strain producing the bacteriocin sakacin P and a Pediococcus acidilactici strain producing another bacteriocin, pediocin AcH, were used as starter cultures under laboratory conditions in a Listeria-seeded raw-pork-meat matrix, which was then stored for 6 weeks at 4 degrees C. At 1 week intervals during the storage period, the antilisterial activity was evaluated. When either strain was added alone, the Listeria monocytogenes cfu count initially dropped from 102 cfu g-1 to an undetectable level by the end of week 1 or 2, but this was followed by a rebound (regrowth) 1 week later. When both strains were added together to the meat matrix, rebound was delayed, Listeria remaining undetected from the end of week 1 to the end of week 5. A rebound was observed 6 weeks post-inoculation, but fewer than 10 cfu g-1 were counted. The use of more than one bacteriocin-producing strain may thus overcome some of the problems limiting the effectiveness of bacteriocins in food systems.