The consumption of fishery products has been steadily increasing in recent decades. Among the quantitatively more important species, the yellowfin tuna (Thunnus albacares), is one of the main at-risk species as regards the possibility to present important levels of histamine and to be associated with the so-called “Scombroid Fish Poisoning”. The main aim of the present study was to evaluate the colorimetric parameters, the occurrence, and the quantification of histamine contamination in yellowfin tuna samples marketed in Sardinia (Italy) by a combination of rapid screening and official control methods. A total of 20 samples of yellowfin tuna loins collected from large retailers, fishmongers and local markets were analyzed for the qualitative and quantitative determination of histamine by the lateral flow test HistaSure™ Fish Rapid Test and LC-MS/MS, respectively. Moreover, all the samples were examined to assess the conformity with the EU rules on labelling and subjected to colorimetric analysis according to the CIE-L*a*b* standard. Visual inspection of yellowfin tuna labels highlighted a 30% of non-compliances. A significant (p < 0.05) difference was reported for brightness (L *), redness (a *), and yellowness (b *). The results of histamine occurrence agreed with the food safety criteria (<100 mg/kg) laid down in EC Regulation 2073/2005 in the 95% and in the 90% of the samples with the rapid screening methods and LC-MS/MS, respectively. A highly significant sessional variation (p < 0.00001) was pointed out. Moreover, the two methods showed an agreement rate of 85%. The results of the present study confirmed the utility of lateral flow tests for the fast qualitative determination of histamine in yellowfin tuna. Rapid screening test should be strengthened by comparison with the official method especially in case of uncertain or positive results.

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.

Fish is one of the major food allergens which, in sensitised individuals, can cause life-threatening allergic reactions, even when present in small amounts. To protect consumers’ health, the correct labeling of foods is important. The objective of the present study was to validate an in-house real-time PCR method targeting the ribosomal 18S rRNA gene as universal DNA marker for the detection of fish in foods. The specificity of the primers was assessed on 20 fish species commonly marketed in the Mediterranean basin and other species of molluscs and crustaceans and foods of animal and plant origin. The absolute detection of the method was assessed using DNA extracted from a fish mixture and the SureFood^® QUANTARD Allergen 40 reference material. The relative amount was assessed on a fish and béchamel sauce blend. Commercial food samples either labelled with or without fish in the ingredient list, were tested for the presence of fish DNA. The primer showed high specificity against the selected fish species. The limit of detection (LOD) and limit of quantification (LOQ) of the in-house method were 0.5 pg/µL and 5 pg/µL, respectively. The relative quantification in fish and béchamel blend samples detected a concentration as low as 0.000025%, corresponding to 0.25 mg/kg of fish, indicating the suitability of the method in a food matrix. The presence of fish DNA was always detected in commercial samples in which the presence of fish was listed in the ingredient list. The method was able to detect the presence of fish DNA also in samples in which the presence of fish was indicated as traces or was not declared on the label. The proposed method was demonstrated to be a reliable, specific, and sensitive method for the detection of fish allergens in foods. Therefore, the proposed real-time PCR method could be used as a useful instrument in the verification of compliance with allergen labelling regulations.

Plastics are non-biodegradable polymers made up of different groups of petrochemical materials. Several biotic and abiotic factors can change the density of plastic fragmenting it and originating microplastics (MPs). MPs have been defined as small pieces of plastic less than 5 mm in size. Due to their small size, they are an emerging concern in the marine environment since they can be ingested by aquatic organisms, especially filter-feeding organisms, such as bivalve mollusks. Impacts of MPs exposure have been shown at various levels of biological organization, from cellular to tissue to individual and population levels. For example, oxidative stress and inflammation have been observed in copepods and mussels, obstruction and physical damage of the digestive tract were found in fish and swimming behavior alterations, disruption of foraging and feeding behavior and overall reduced fitness and survival were observed in fish and oysters. In addition, MPs can act as a vector for the transfer of chemicals to marine biota. The aim of the present study was the identification and quantification of potential MPs in shellfish harvested in Sardinia (Italy) by using transillumination stereomicroscopy. Bivalves were collected from 4 of the main production areas located along the Sardinian coast and selected according to the principles of the risk assessment. The results of the present study demonstrated the presence of potential MPs in 70% of the analyzed samples: the presence of MPs in bivalve mollusks may pose a threat to food safety, and there is an urgent need to evaluate the potential risks of MPs 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.

Bivalve mollusk production represents the principal aquaculture activity in Sardinia (40°03′ N, 9°05′ E). In 2021, 859 water samples and 1270 mollusk samples were analyzed. The species Alexandrium minutum caused the accumulation of Paralytic Shellfish Toxins (PST) in three samples of bivalve mollusks. Dinophysis acuminata complex caused the accumulation of lipophilic toxins (LTs) belonging to the okadaic acid group (OAs) in 18 samples of bivalve mollusks. The research of paralytic shellfish toxins (PSTs) in shellfish samples has been carried out with LC-FLD, as mentioned in the AOAC 2005 Official Method 2005.06. The determination of LTs was carried out by LC-MS/MS analysis. DTX2, belonging to the group of OA toxins, was detected for the first time in Sardinia, in mussels sampled in Tortolì. The presence of Dinophysis and Prorocentrum species was correlated with the accumulation of the OA toxin group in bivalve mollusks, showing a certain repeatability at certain times of the year in the areas included in the study. The results of the present study can help to plan and organize more effective bio-monitoring sampling strategies.