Inhibitory Effect of Lactiplantibacillus plantarum and Lactococcus lactis Autochtonous Strains against Listeria monocytogenes in a Laboratory Cheese Model

In the present study, six Lactococcus lactis and seven Lactiplantibacillus plantarum strains isolated from artisanal Sardinian dairy products were evaluated for their efficacy in controlling the growth of Listeria monocytogenes during the storage of miniature fresh cheese manufactured on a laboratory scale to exploit their possible use as biopreservatives. The strains were tested for antimicrobial activity and some technological characteristics before using them in miniature fresh cheese to evaluate their in situ antilisterial effect. Our results showed that five strains (L. lactis 16FS16-9/20234-11FS16 and Lpb. plantarum 1/14537-4A/20045) could be considered suitable candidates for use as protective cultures in fresh cheese manufacture since they significantly lowered the pathogen counts by 3–4 log units compared to the control; however, all strains tested were capable of decreasing L. monocytogenes numbers. Our results suggest that the single and combined action of the acidifying power and the production of bacteriocin of these strains was capable of controlling and/or reducing the growth of L. monocytogenes. Considering their technological characteristics, they might be used as starter/adjunct cultures to increase the safety of the products, perhaps in association with other antimicrobial hurdles.