Occurrence of antilisterial structural bacteriocins genes in meat borne lactic acid bacteria

FONTANA, CECILIA; COCCONCELLI, PIER. S.; VIGNOLO, GRACIELA; SAAVEDRA, LUCILA

Valencia

Simposio; 2do. International Symposium on Fermented Meat; 2014

CSIC

Despite the progress in food biotechnology, meat industry is still under scrutiny due to the frequent outbreaks of foodborne illness. L. monocytogenes is a food-borne pathogen capable of surviving unfavorable environmental conditions, such as low pH and high sodium chloride levels, contaminating the end-products. Ready-to-eat foods, including fermented meat are considered as high risk products and this microorganism cannot be completely eliminated even when many risk assessment strategies have been developed for its control. Biopreservation by using bacteriocinogenic LAB has gained increased attention as a means of naturally controlling the shelf life and safety of meat products. The ability to inhibit the growth of Listeria cells and the presence of bacteriocin encoding genes was examined in 115 LAB strains isolated from Argentinean vacuum-packaged beef and different traditional fermented sausages. Lactobacillus sakei, Lactobacillus curvatus and Enterococcus faecium showed a great inhibition of all Listeria strains evaluated while Pediococcus acidilactici and Lactobacillus plantarum demonstrated a limited or absent antilisterial activity. Both L. curvatus and L. sakei carried the sppA, sppQ and sapA structural genes, encoding for sakacin P, sakacin Q and curvacin A bacteriocins, respectively. Whilst L. curvatus exhibited a higher occurrence of these genes, L. sakei strains were more effective at inhibiting Listeria strains, L. monocytogenes UC8159 and L. innocua 7 being the most sensitive to these bacteriocins. Among analyzed E. faecium strains, the wide distribution of entA, entB and entP genes accounted for the high antilisterial activity particularly observed against L. monocytogenes FBUNT. The structural gene plantEF was mostly present in Lactobacillus plantarum strains and no pedA gene was found in P. acidilactici evaluated strains. The antilisterial potential of L. sakei and E. faecium offers great possibilities for the meat industry as biopreservative cultures, although more studies are needed in order to conclude about this issue.