Synergistic antimicrobial effect of lactocin AL 705 and nisin combined with organic acid salts against Listeria innocua 7 in broth and a hard cheese

VERDI, MARÍA CLARA; MELIAN, CONSTANZA; CASTELLANO, PATRICIA; VIGNOLO, GRACIELA; BLANCO MASSANI, MARIANA

INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2019 vol. 55 p. 267 - 275

0950-5423

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), potassiumsorbate (PS), calcium propionate (CP) and sodium lactate (SL), Nis + PS being the most effectivebinary 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-MICcombinations of the antimicrobials exerted bactericidal activity against L. innocua 7 after AL705 additionto the binary mixtures. However, when applied on Sardo cheese contaminated with L. innocua 7 (initialinoculum 4.45 0.06 CFU g1), only Nis + PS + AL705 produced count reductions respect to the control,reaching 3.04 0.35 CFU g1 counts after 15 days at 15 °C. Ternary combinations containingAL705 showed potential to reduce antimicrobial usages for L. innocua 7 inhibition