The interaction of the non-bacteriocinogenic Lactobacillus sakei 10A and lactocin S producing Lactobacillus sakei 148 towards Listeria monocytogenes on a model cooked ham.
Two lactic acid bacteria, Lactobacillus sakei subsp. carnosus (10A) and lactocin S producing Lactobacillus sakei 148 (LS5), were examined for their usefulness as protective culture in the biopreservation of cooked meat products. Co-culture experiments on a model cooked ham (MCH) between 10A or LS5 and a cocktail of three Listeria monocytogenes strains were performed to examine the influence of inoculum level (10(5) vs. 10(6)cfu/g), storage temperature (4 vs. 7 degrees C) and packaging type (vacuum-packaging vs. modified atmosphere-packaging). At 7 degrees C, applying Lactobacillus sakei 10A at 10(6) cfu/g limited the growth of Listeria monocytogenes to <1 log(10) cfu/g during 27 days, whilst an application level of 10(5) cfu/g failed to prevent growth to unacceptable levels. Lactobacillus sakei LS5 did not demonstrate an antagonistic effect towards Listeria monocytogenes. Lowering the temperature to 4 degrees C or switching from vacuum-packaging to modified atmosphere packaging (MAP) did not influence the ability of strain 10A to grow on the MCH, as its dominance did not change. A combination of strain 10A and 4 degrees C or a MAP containing 50% CO(2) completely inhibited the growth of Listeria monocytogenes. Sensory assessments and pH measurements confirmed that 10A, even when present at a high level for prolonged storage times, did not acidify the cooked ham to a point of sensory rejection.
Vermeiren
L
L
Laboratory of Food Microbiology and Food Preservation, Faculty of Bioscience Engineering, Gent University, Department of Food Safety and Food Quality, Coupure Links 653, B-9000 Gent, Belgium.
Devlieghere
F
F
Vandekinderen
I
I
Debevere
J
J
D000818:Animals; D000898:Antibiosis; D001430:Bacteriocins; D018920:Coculture Techniques; D015169:Colony Count, Microbial; D003258:Consumer Behavior; D003257:Consumer Product Safety; D005516:Food Microbiology; D018857:Food Packaging / Q000379:methods*; D005519:Food Preservation / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D007778:Lactobacillus / Q000378:metabolism / Q000502:physiology*; D008089:Listeria monocytogenes / Q000254:growth & development*; D008461:Meat Products / Q000382:microbiology*; D010455:Peptides / Q000494:pharmacology*; D013552:Swine; D013649:Taste; D013696:Temperature; D014618:Vacuum
D001430:Bacteriocins; D010455:Peptides; C103925:lactocin S