Annual and interannual dynamics of shellfish toxins and associated harmful algal species (HAS) were analyzed from 2015 to 2020 in Tortolì Lagoon (Sardinia, west Mediterranean Sea). Analysis of seasonal occurrence of different harmful algae, such as Dinophysis spp., Prorocentrum spp., Pseudo-nitzschia spp. and Alexandrium minutum, was performed. The species Dinophysis acuminata and Dinophysis sacculus were responsible for the accumulation of lipophilic toxins belonging to the okadaic acid group (OAs) and pectenotoxins2 (PTX2) in bivalve mollusks. The highest HAS detection was recorded in the winter months; in particular, Dinophysis spp. was mostly present in January–February. Out of 1090 analyzed mollusk samples, 39 were non-compliant, exceeding the legal limits (160 μg OA eq/kg e.p.) reported in Regulation 853/2004 of the European Commission. A statistical analysis related to the presence of OA and PTX2 in mollusks with various environmental parameters (pH, water temperature, dissolved oxygen, algal density) was implemented, proving a clear winter seasonality. The present study highlights the necessity to better understand the different factors able to influence the production and accumulation of toxins in bivalve mollusks bred in an important Sardinian production area. The contribution of this research is important not only from an environmental and productive point of view but also from the view of implementing management in order to mitigate any harm to human health.

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 .