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In the present study, we investigated the presence, seasonal distribution, and biomolecular characteristics of Vibrio parahaemolyticus and Vibrio vulnificus in samples of bivalve mollusks (Mytilus galloprovincialis, Crassostrea gigas, and Ruditapes decussatus) harvested and marketed in Sardinia (Italy) between 2017 and 2018. A total of 435 samples were submitted for qualitative determination of Vibrio spp., V. parahaemolyticus, and V. vulnificus. Potentially enteropathogenic isolates were detected with biomolecular methods. The overall prevalence of Vibrio spp. was 7.6%. The highest Vibrio prevalence was found in R. decussatus (8.3%). The prevalences of V. parahaemolyticus and V. vulnificus were 2.7 and 4.8%, respectively. Higher prevalences of V. parahaemolyticus and V. vulnificus were found in R. decussatus (4.2%) and C. gigas (6.2%), respectively. Only two pathogenic V. parahaemolyticus strains were recovered (genotypes: tdh- and trh+; tdh+ and trh-), both from M. galloprovincialis. None of the isolates were tdh+ and trh+. Pathogenic Vibrio infections are often underestimated, and human infections are increasing in Europe. European data on the true distribution of Vibrionaceae are scarce, and the results of the present study highlight the need of constant monitoring to update the distribution of pathogenic vibrios. HIGHLIGHTS

The consumption of fishery products has been steadily increasing in recent decades. Among the quantitatively more important species, the yellowfin tuna (

The aims of this paper were to collect and analyse preliminary data of phytoplankton in the water, biotoxins

The present study aimed to determine trace elements in Mediterranean mussels (

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.

In Sardinia (Italy), bivalve molluscs production plays an important role in the trade balance. Diarrhoetic shellfish poisoning (DSP), an intoxication caused by the ingestion of bivalve molluscs that have accumulated high levels of Okadaic acid (OA), may represent a serious risk for the public health and a remarkable economic loss for the producers. Aim of this work was to improve knowledge about the repeatability of OA accumulation phenomena in various seasons trying to understand whether or not there was a trend. Also, the interaction between toxic algae and OA accumulation was examined. In this study, data of lipophilic toxins, water temperature and abundance of DSP-producing microalgal species were collected in a four-year period (2015–2018) in coastal production areas of Sardinia. Several episodes of OA positive values (>160 eq μgAO/Kg pe, Reg 853/04) were recorded during the study period in different production areas of Sardinia and in different seasons. A seasonal repeatability of OA accumulation in molluscs was observed in some production areas; moreover, different temporal gaps between the presence of toxic algae and OA accumulation were reported. Toxicity was observed almost exclusively in Mytilus galloprovincialis Lamark (99%), being this matrix the most abundant species bred in Sardinia.

The occurrence of 21 trace elements in native Mediterranean mussel (Mytilus galloprovincialis) from the Calich Lagoon, a typical brackish area of the northwest of Sardinia (Italy), was investigated. The seasonal variation of metals in bivalves was considered, and the highest values were found in spring and summer; in particular, a high significant (P

Several planktonic dinoflagellates canproduce lipophilic phycotoxins that representa significant threat to public health aswell as to shellfish and fish farming.Poisoning related to some of these toxins iscategorised as diarrhetic shellfish poisoning.We analysed 975 shellfish samplesfrom Tortolì in the central-eastern region ofSardinia (Italy) from January 2016 toMarch 2020, to investigate the prevalenceof different lipophilic marine biotoxins inmollusc bivalves. The results highlightedthe predominant presence of toxins belongingto the okadaic acid group in all sampleswith toxin concentrations exceeding legallimits, and revealed the new occurrence ofpectenotoxins in oysters and clams with awinter seasonality in recent years. The originof shellfish toxicity was associated with the same Dinophysis species, mainly D.acuminata. Based on both these results andother precedents, monitoring and recording systems are strongly recommended.

Introduction Diarrhoetic shellfish poisoning (DSP), an alimentary intoxication known to lead to intestinal symptoms, and caused by toxins produced by some dinoflagellates (including several Dinophysis), represents a serious threat to public health. The aim of this paper was to provide information about the occurrence and abundance of potentially toxic harmful algal species causing DSP, and the associated concentration of okadaic acid (OA) toxins. The departing assumption was that in the study area there was an increase in the presence both of Dinophysis species and OA and its derivates that could result in a risk to the health of seafood consumers. Material and Methods During 2015–2016, water and shellfish samples were collected in the Mediterranean area (Sardinia, Italy). Dinophysis cells were counted according to Utermöhl’s method from water samples, while mass spectrometry was used to identify lipophilic toxins in molluscs. Results A total of 46 non-compliant samples of Mytilus galloprovincialis were observed. Their non-compliance concerned their OA levels above the legal limit. Among toxic dinoflagellates, D. acuminata and D. sacculus were the species found mostly during DSP events. Conclusion No cases of human intoxication have been reported, but continuous surveillance of toxic phytoplankton is necessary to predict and prevent its harmful effects on human health.

Calich Lagoon is a Mediterranean coastal lagoon located along the northwestern coast of Sardinia (Italy). The connection to marine and fresh water determines the high productivity of this coastal lagoon. Despite its great potential and the presence of natural beds of bivalve mollusks (Mytilus galloprovincialis), the lagoon has not yet been classified for shellfish production. In this study, through a multidisciplinary approach, the presence of several bacterial pathogens (Escherichia coli, Salmonella spp., and Vibrio spp.) and viral pathogens (hepatitis A virus and norovirus genogroups I and II) was evaluated from March 2017 to February 2018. In addition, phytoplankton composition in lagoon waters and associated algal biotoxins (paralytic and diarrhetic shellfish poisoning) in mussels were also monitored. The aim of this study was to provide useful data to improve knowledge about their seasonal presence and to assess the potential risk for public health, as well as to provide input for future conservation and management strategies. In mussels, Salmonella spp. were found in spring, along with E. coli, but Salmonella spp. were not found in autumn or winter, even though E. coli was detected in these seasons. Vibrio parahaemolyticus was found in autumn and winter, but not in spring. Norovirus genogroups I and II were found in winter samples. None of the bacteria were found in summer. Algal biotoxins have never been detected in mussel samples. Among potentially harmful phytoplankton, only Pseudo-nitzschia spp. were present, mainly in summer. The results showed that a possible bacterial and viral contamination, together with the presence of potentially toxic microalgae, is a real problem. Therefore, the development of natural resource management strategies is necessary to ensure the good quality of waters and guarantee the protection of consumers.

This work reports the first communication relating to the presence of yessotoxins in Mytilus galloprovincialis from coastal mussel farms (Sardinia, western Mediterranean) detected during 2008 and 2013 through a monitoring programme. The paper emphasizes how the changes both in yessotoxin permitted limits and used methods, established by legislation, have influenced the interpretation of the obtained results. Consequently, the samples that resulted negative during 2008 would have been positive until August 2013 and negative from September 2013 up to now, and the samples that were positive in 2013 would have been positive in 2008 and negative nowadays, according to Regulation currently in force. Regular monitoring of biotoxins demonstrated that, although yessotoxins have been rarely present in the past in Sardinia, they may cause toxicity in shellfish. So, it’s important to keep up on legislation’s changing and laboratory methods.

Sardinia (Italy, north-western Mediterranean) is a commercially important producer of edible bivalve molluscs. Since the early 2000s, it was subjected to recurring cases of mussel farm closures due to toxic algal poison. Here, we present the studies on toxin concentrations and the associated potentially toxic phytoplankton distribution and abundances carried out by a regular monitoring programme in Sardinian shellfish areas, from January to May 2015. Diarrheic shellfish poisoning (DSP) toxins were detected in several bivalve molluscs samples, while paralytic shellfish poisoning (PSP) and paralytic shellfish poisoning toxins were present just once, without exceeding the legal limits. Potentially toxic algal species have been constantly present.

Several microalgae of the genus Alexandrium (Alexandrium minutum and Alexandrium catenelle) can produce an algal biotoxin, the paralytic shellfish poison (PSP) that can be accumulated in the shellfish edible tissues making them hazardous to the consumer’s health. In this paper we report i) the results of PSP toxins survey carried out by mouse bioassays (mouse test AOAC 958.08) on 7457 samples of bivalve molluscs farmed in Sardinia and in other European countries and marketed in Sardinia region from 2002 to 2011, and ii) the management of positive cases. Based on our experience it is very important to strictly apply the planned activities in order to prevent any risk and to protect the consumer’s and producer’s health.

In this study, a total of 150 samples including cloacal, carcass swabs, and neck skin excisions were collected from 50 broiler chickens randomly selected in three Italian poultry slaughterhouses. All the samples were examined for the presence of food-borne pathogens and process hygiene indicators. The efficacy of a destructive method and a non-destructive method for recovering of bacteria was also evaluated. Fifteen Listeria monocytogenes isolates were subjected to serotyping and investigated for the presence of 10 virulence-associated genes using multiplex PCR assays. The strains were further subjected to PFGE and investigated for their adhesion abilities. The average levels of the process hygiene indicators (total viable counts of aerobic bacteria, total coliforms, and Escherichia coli) were lower than other surveys carried out in Italy, on the contrary, we highlighted the occurrence of food-borne pathogens as Staphylococcus aureus, Clostridium perfringens, Campylobacter jejuni, and L. monocytogenes. The recovering of L. monocytogenes serotype 1/2a involved in the majority of recent EU food-borne outbreaks of human listeriosis should be considered a public health concern. Practical applications There are a few studies about the occurrence of the main food-borne pathogens and the presumptive process hygiene indicators in Italian poultry slaughterhouses. In our study, we applied a combined microbiological and biomolecular approach to verify their occurrence, to evaluate the practical application of recovery methods and to characterize eventual Listeria monocytogenes isolates. The slaughterhouses included in our study were comparable for slaughter procedures: our results should be useful for Food Business Operators to demonstrate the effectiveness of the preventative measures.