ATTIVITÀ ANTIMICROBICA DI BATTERI LATTICI (LAB) ISOLATI DA FILETTI DI SPIGOLA (DICENTRARCHUS LABRAX) E ORATA (SPARUS AURATUS) CONFEZIONATI IN ATMOSFERA PROTETTIVA VERSO CEPPI AUTOCTONI DI LISTERIA MONOCYTOGENES

The natural lactic flora of the artisanal chilli ???Tramonti??? cheese, a typical product manufactured in the ???Lattari mountains???, area of Salerno province (Italy), was investigated. Particular attention was paid to the growth dynamics assessment and to the molecular identification of the indigenous lactic acid bacteria involved in the ripening of this cheese made with raw sheep milk without starter cultures. One batch was monitored taking 4 sample on 0, 30, 50 and 105 ripening days. Lactobacillus and Lactococcus were enumerated and randomly isolated on MRS and LM17 agar (32ºC x 48h -mesophilic flora- and 42°C x 48h -thermophilic flora), respectively. N. 66 presumptive lactic acid bacteria isolates, gram positive and catalase negative, were genotipically identified by Ribotyping. Mesophilic Lactobacillus remained at levels of 107 cfu/g during whole maturation time and thermophilic Lactobacillus, from initial values of 105 cfu/g, reached concentratios of 106 cfu/g at the end of maturation. Mesophilic and thermophilic Lactococcus showed, on average, levels of 106 since the beginning of the ripening. Ribotyping allowed to detect 4 lactic acid bacteria species: Enterococcus faecium (65,15%), Lactococcus lactis spp. cremoris (24,24%), Enterococcus faecalis (6,06%) and Enterococcus durans (4,54%), showing the diversity of indigenous lactic acid bacteria of chilli ???Tramonti??? cheese.