Microbial, chemico-physical and volatile aromatic compounds characterization of Pitina PGI, a peculiar sausage-like product of North East Italy.

Pitina is a fermented sausage-like produced in the mountainous area of the North-East Italy by artisanal plants without the use of both selected starters and casing (Slow Food Presidium). Originally, Pitina has been a way of preserving meat and it is manifactured by meat from ungulates mixed with pork lard, smoked, dryed and ripened. In this study, microbial ecology, physic-chemical parameters, and volatile aromatic compounds of Pitina SR and LR, which differ by the duration of ripening processes, were investigated. Results showed the good hygienic quality. Staphylococcus xylosus and Lactobacillus sakei were responsible for the ripening. Other Coagulase-negative Catalase-positive Cocci (CNCPC) and LAB species were identified: S. equorum, S. warneri, S. succinus and Carnobacterium divergens, Streptococcus equinus, Kocuria rhizophila. Giberella moniliformis and Penicillium turbatum were the only mould species isolated. Strain characterization demonstrated a high genetic variability. Raw meat, environment and ripening conditions seemed to affect strains distribution, which had an impact on the aromatic profile of the product.

Description of the microflora of sourdoughs by culture-dependent and culture-independent methods.

Four types of sourdoughs (L, C, B, Q) from artisanal bakeries in Northern Italy were studied using culture-dependent and culture-independent methods. In all samples, the yeast numbers ranged from 160 to 10(7)cfu/g, and the numbers of lactic acid bacteria (LAB) ranged from 10(3) to 10(9)cfu/g. The isolated LAB were sequenced, and a similarity was noted between two samples (C, Q), both in terms of the species that were present and in terms of the percentage of isolates. In these two samples, Lactobacillus plantarum accounted for 73% and 89% of the bacteria, and Lactobacillus brevis represented 27% and 11%. In the third sample (B), however, the dominant LAB isolate was Lb. brevis (73%), while Lb. plantarum accounted for only 27%. The fourth sourdough (L) was completely different from the others. In this sample, the most prominent isolate was Weisella cibaria (56%), followed by Lb. plantarum (36%) and Pediococcus pentosaceus (8%). In three out of four samples (L, C and Q), all of the yeasts isolated were identified as Saccharomyces cerevisiae, yet only Candida humilis (90%) and Candida milleri (10%) were isolated in the fourth sample (B). The microbial ecology of the sourdoughs was also examined with direct methods. The results obtained by culture-independent methods and DGGE analysis underline a partial correspondence between the DNA and RNA analysis. These results demonstrate the importance of using a combined analytical approach to explore the microbial communities of sourdoughs.