Synergistic antimicrobial effect of lactocin AL705 and nisin combined with organic acid salts against Listeria innocua 7 in broth and a hard cheese |
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Authors: | María Clara Verdi Constanza Melian Patricia Castellano Graciela Vignolo Mariana Blanco Massani |
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Affiliation: | 1. Instituto Nacional de Tecnología Industrial (INTI), Av. Gral. Paz 5445, 1650 San Martin, Argentina;2. Centro de Referencia para Lactobacilos (CERELA), CONICET, Chacabuco 145, 4000 Tucumán, Argentina
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Av. Rivadavia 1917, C1033AAJ Buenos Aires, Argentina;3. Centro de Referencia para Lactobacilos (CERELA), CONICET, Chacabuco 145, 4000 Tucumán, Argentina |
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Abstract: | The effectiveness of antimicrobial mixtures against Listeria innocua 7, used as a L. monocytogenes surrogate, was investigated in broth and a food system. Synergistic effects were found for nisin (Nis), potassium sorbate (PS), calcium propionate (CP) and sodium lactate (SL), Nis + PS being the most effective binary mixture that exhibited listericidal activity in broth. To assess the effect of adding lactocin AL705 (AL705) to Nis + organic acid salt combinations, tridimensional isobolograms were generated. Sub-MIC combinations of the antimicrobials exerted bactericidal activity against L. innocua 7 after AL705 addition to the binary mixtures. However, when applied on Sardo cheese contaminated with L. innocua 7 (initial inoculum 4.45 ± 0.06 CFU g?1), only Nis + PS + AL705 produced count reductions respect to the control, reaching 3.04 ± 0.35 CFU g?1 counts after 15 days at 15 °C. Ternary combinations containing AL705 showed potential to reduce antimicrobial usages for L. innocua 7 inhibition. |
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Keywords: | Anti-listerial synergistic activity bacteriocins calcium propionate lactocin AL705 nisin potassium sorbate sodium lactate |
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