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Pediococcus pentosaceus LBM 18 has shown potential as producer of an antibacterial and antifungal bacteriocin-like inhibitory substance (BLIS). BLIS inhibited the growth of spoilage bacteria belonging to Lactobacillus, Enterococcus and Listeria genera with higher activity than Nisaplin used as control. It gave rise to inhibition halos with diameters from 9.70 to 20.00 mm, with Lactobacillus sakei being the most sensitive strain (13.50-20.00 mm). It also effectively suppressed the growth of fungi isolated from corn grain silage for up to 25 days and impaired morphology of colonies by likely affecting fungal membranes. these results point out that P. pentosaceus BLIS may be used as a new promising alternative to conventional antibacterial and antifungal substances, with potential applications in agriculture and food industry as a natural bio-controlling agent. Moreover, cytotoxicity and cell death induction tests demonstrated cytotoxicity and toxicity of BLiS to human colon adenocarcinoma caco-2cells but not to peripheral blood mononuclear cells, with suggests possible applications of BLIS also in medical-pharmaceutical applications. Lactic acid bacteria (LAB) are a group of well-distributed microorganisms in nature 1-3 having lactic acid as the major product of sugar fermentation 4,5. They are Gram-positive, non-pathogenic, non-sporulating, facultative anaerobic, catalase negative and acid tolerant bacteria with a strictly fermentative metabolism 3,6 , which are often used as industrial starter cultures in food fermentation technology 7,8. Their metabolic products are recognized as Generally Regarded as Safe (GRAS) by the Food and Drug Administration (FDA) and recommended by the Qualified Presumption of Safety (QPS) list of the European Food Safety Authority (EFSA) 9. This means that they can be safely used to preserve foods 10,11 , hence offering important benefits to the food industry 12. From the technology point of view, the most important genera of LAB are Aerococcus, Carnobacterium,

The growing demand of consumers for synthetic chemical-free foods has increased the search for natural preservatives such as bacteriocins and bacteriocin-like inhibitory substances (BLIS) to give them adequate microbiological safety, sensory characteristics, and shelf life. In this study, the antimicrobial activity of BLIS produced by Pediococcus pentosaceus ATCC 43200 was compared with that of nisin. Lactobacillus sakei ATCC 15521, Listeria seeligeri NCTC 11289, Enterococcus En2052 and En2865, and Listeria monocytogenes CECT 934 and NADC 2045 exhibited larger inhibition halos in BLIS-treated than in Nisaplin-treated samples, unlike Listeria innocua NCTC 11288. In artificially contaminated ready-to-eat pork ham, BLIS was effective in inhibiting the growth of L. seeligeri NCTC 11289 for 6 days (counts from 1.74 to 0.00 log CFU/g) and ensured lower weight loss (2.7%) and lipid peroxidation (0.63 mg MDA/kg) of samples compared with the control (3.0%; 1.25 mg MDA/kg). At the same time, coloration of ham samples in terms of luminosity, redness, and yellowness as well as discoloration throughout cold storage was not influenced by BLIS or Nisaplin taken as a control. These results suggest the potential use of P. pentosaceus BLIS as a biopreservative in meat and other food processing industries.