No abstract

No abstract

In the present study, we aimed to investigate the presence, seasonal distribution and biomolecular characterization of Vibrio parahaemolyticus and Vibrio vulnificus in samples of bivalve molluscs ( Mytilus galloprovincialis, Crassostrea gigas, Ruditapes decussatus, Venus verrucosa and Solen vagina ) and gastropod molluscs (Murex brandaris) harvested and marketed in Sardinia (Italy) between 2017 and 2018. A total of 444 samples were submitted to qualitative determination of Vibrio spp., V. parahaemolyticus and V. vulnificus. Identification and virulence profile of the isolated strains were performed by biomolecular methods. The overall prevalence of Vibrio spp. was 7%. The highest prevalence was pointed out in R. decussatus (8.3%). The prevalence of V. parahaemolyticus and V. vulnificus were 2.7% and 4.7% respectively. Higher levels of V. parahaemolyticus and V. vulnificus prevalence were highlighted in R. decussatus (4.2%) and C. gigas (6.2%) respectively. Potentially pathogenic V. parahaemolyticus strains were a minority ( n. 2 isolates tdh-/trh+ and n. 1 isolate tdh+/trh- ) and were recovered from M. galloprovincialis . None of the isolates was tdh+/ trh+. Pathogenic Vibrios infections are often underestimated and the reports of human infections in Europe are constantly increasing. European data on the true distribution of Vibrionaceae are scarce: the results of the present study highlight the need of constant monitoring plans to update the distribution of potentially pathogenic Vibrios.

The aim of the present study was the determination of Listeria monocytogenes , competitive microbiota, microbial hygiene indicators and physico-chemical parameters in the typical Mediterranean Style fermented sausages “Salsiccia Sarda” . A batch of “Salsiccia Sarda” (25 samples) naturally contaminated by L. monocytogenes and vacuum packaged after 24 days of ripening was included in the study. Fifteen samples stored at 8° C were analysed after 13, 90 and lastly at the end of shelf-life, after 180 days from vacuum packaging. Ten vacuum packaged samples were stored at 12°C in a domestic fridge simulating temperature abuse and were evaluated at the end of the shelf-life. Samples were subjected to physico-chemical analysis (pH and aw) and investigated for the presence and enumeration of L. monocytogenes . Competitive microbiota, Lactic Acid Bacteria (LAB) and Coagulase negative Staphylococci (CNS), and microbial hygiene indicators (Total mesophilic bacterial counts, Enterobacteriaceae, Enterococcuss spp. and Staphylococcus aureus ) were determined in all the samples. Although a decreasing trend in L. monocytogenes prevalence was observed through the shelf-life, the detection of the pathogen in fermented sausages confirms the ability of L. monocytogenes to overcome the hurdles of the manufacturing process. The results of the present study highlight the importance to carefully evaluate the “Salsiccia Sarda” production process by Food Business Operators (FBOs) in order to maintain unfavourable conditions for the growth of L. monocytogenes .

No abstract