Preliminary investigation on the microbiological quality of edible marine gastropods of the Adriatic Sea, Italy.

According to the European Legislation, marine gastropods placed unprocessed on the market must comply with the same requirements established for live bivalve molluscs but, being considered not filterfeeding and unable to concentrate fecal contaminants, they may be harvested outside the classified areas. Despite this statement, little scientific information is available on the microbiological quality of these animals. The aim of the present study was to investigate 28 batches of edible snails of the Adriatic Sea, namely Nassarius mutabilis and Bolinus brandaris, with respect to i) smell and viability, by a method here reported; ii) the bacterial component of the whole body referred to E. coli, Vibrio spp., V. parahaemolyticus, V. vulnificus, V. cholerae and V. alginolyticus. A total of 21 batches of N. mutabilis and 7 batches of B. brandaris were analyzed. Batches of both species retrieved from the primary production were all largely composed of viable animals, had saltwater/neutral smell, and showed mean value of Vibrio spp. of 5,34 and 5,79 log10 UFC g-1 in N. mutabilis and B. brandaris respectively. 47% of the batches of N. mutabilis retrieved from the market, were largely composed of dead animals, had acrid/nasty smell, and showed mean value of Vibrio spp. of 6,53 log10 UFC g-1. E. coli, V. vulnificus and V. cholerae were never detected, but all samples were positive for V. alginolyticus. One sample of B. brandaris was positive for V. parahaemolyticus genotyped by PCR at the specie level (ToxR+) and positive for the thermostable direct hemolysin gene (tdh+)

Hazard Identification Related to the Presence of Vibrio spp., Biogenic Amines, and Indole-Producing Bacteria in a Non-Filter Feeding Marine Gastropod (Tritia mutabilis) Commercialized on the Italian Market

open4noTritia mutabilis is a carrion-feeder edible marine gastropod with an open circulatory sys- tem. Therefore, biological, and chemical contaminants associated with the feed can reach all body tissues. The aim of the present study was to investigate the possible association of these char- acteristics with some food safety hazards. Vibrio spp. load, and the prevalence of pathogenic V. parahaemolyticus, V. vulnificus, and V. cholerae, were investigated. Moreover, biogenic amines (BAs) and indole-producing bacteria (IPB), markers of seafood decomposition, were quantified for the first time in an edible carrion-feeder. Overall, 49 batches were analyzed (38 from retail, and 11 from primary production). The Vibrio spp. load resulted of 5.64 ±0.69 log10 CFU g−1 at retail, and 5.27 ±0.74 at harvest but all batches resulted negative for pathogenic Vibrio. Histamine, putrescine, cadaverine, and tyramine were detected both at harvest and at the retail level. Their sum (BAs Index) showed a mean value of 50.45 and 65.83 mg Kg−1 in batches at harvest and at retail, respec- tively. IPB were detected at harvest and upon refrigeration for three days (T1–T3). The mean load resulted in 2.52 ±0.85 log10 MPN g−1 at T0, 3.31 ±1.23 at T3 in batches immediately refrigerated, and 3.22 ±1.18 at T3 in batches previously immersed in clean seawater. Our results contribute to identifying food-borne hazards for T. mutabilis that may be related to the retention of biogenic amines and indole-producing bacteria due to carrion feedingopenSerratore, Patrizia; Bignami, Giorgia; Ostanello, Fabio; Lorito, LunaSerratore, Patrizia; Bignami, Giorgia; Ostanello, Fabio; Lorito, Lun

Analisi multifattoriale e di sicurezza alimentare di gasteropodi marini destinati al consumo umano

The present thesis aims to evaluate a method to assess the viability; estimate the bacterial and viral (Hepatitis A and Norovirus) contamination; describe how some parameters change during a week in refrigerated condition and after 24 hours of immersion; estimate indole-producing bacteria and biogenic amines; evaluate the presence of saxitoxin and tetrodotoxin. The method to assess the viability using sea salt is easy to apply. Marine gastropods did not accumulate fecal contaminants, but vibrios due to their feeding. The Vibrio spp. load was even higher than the one registered on Ruditapes philippinarum belonging to the same area For what to concern the evaluation during a week in refrigerated condition and after 24 hours of immersion, non-re-immersed gastropods exceeded the acceptable mortality (10%) after three days in refrigerated conditions, but the Vibrio spp. load did not show a significant increase within three days. The TVC was already high from the beginning and its major part consisted of SSOs, which could be explained by gastropods’ feed, such as the Pseudomonas spp. load and the abundance of IPB. The BAs amount was also correlated with viability and had a statistically significant difference within a week on refrigerated conditions, principally because putrescine, tyramine, spermidine, and cadaverine rise in non-re-immersed samples. It also should be noted that the BAs amount was higher on average than the recommendation of literature. Moreover, re-immersed batches showed acceptable viability even after 3 days, and the Vibrio spp. load, TVC, SSOs, and biogenic amines remained almost constant within a week contrary to non-re-immersed samples. Finally, T. mutabilis and B. brandaris did not accumulate NoVs and TTX. We obtained only one positivity of the HAV sample and traces of STX (not at levels toxic to humans). Our results contribute to identifying food-borne hazards for T. mutabilis and B. brandaris

Indagine preliminare sulla componente batterica di gasteropodi marini eduli dell\u2019Adriatico

INDAGINE PRELIMINARE SULLA COMPONENTE BATTERICA DI GASTEROPODI MARINI EDULI DELL\u2019ADRIATICO Patrizia Serratore, Emanuele Zavatta, Giorgia Bignami, Luna Lorito Dipartimento di Scienze Mediche Veterinarie \u2013 Universit\ue0 di Bologna 1. Scopo Il Reg. CE 558/2010 dispone che la cattura dei gasteropodi marini, assimilati dal Reg. CE 853/2004 ai molluschi bivalvi vivi, pu\uf2 avvenire al di fuori delle aree classificare, in quanto non essendo filtratori non accumulano microrganismi contaminanti di origine fecale. Nonostante questo assunto, va rilevato che le conoscenze scientifiche sul microbiota dei gasteropodi marini eduli sono molto scarse, inoltre manca un metodo standardizzato per verificarne la vitalit\ue0 in commercio. Lo stesso Food and Veterinary Office comunitario rileva che i Controlli Ufficiali negli Stati membri risultano totalmente assenti o comunque inappropriati. Al fine di implementare le opportune pratiche ispettive, \ue8 necessario sviluppare indagini mirate sul piano della sicurezza alimentare di questi prodotti. Il presente studio offre un primo contributo di conoscenza sulla componente batterica associata a due specie dell\u2019Adriatico, Nassarius mutabilis e Bolinus brandaris, proponendo un metodo ispettivo per la verifica della vitalit\ue0. 2. Metodi Complessivamente sono stati analizzati 21 lotti di Nassarius mutabilis e 7 di Bolinus brandaris. La vitalit\ue0 \ue8 stata verificata mediante aspersione con sale da cucina, metodo messo a punto dal nostro laboratorio. Le unit\ue0 campionarie, dopo accurato risciacquo in acqua marina sterile, sono state sottoposte ad analisi batteriologiche: enumerazione di Vibrio spp., come componente autoctona, su Thiosulfate-Citrate-Bile salts-Sucrose Agar NaCl 3% finale, incubato a 20\ub0C per 3-5 gg; ricerca mirata di V. parahaemolyticus, V. vulnificus, V. cholerae e V. alginolyticus su CHROMagar Vibrio incubato a 37\ub0C per 24 h, e caratterizzazione fenotipica e genomica degli isolati (metodo interno); enumerazione di E. coli, come criterio di sicurezza, con metodo ISO 16649-2:2001. 3. Risultati Tutti i lotti acquisiti direttamente dal produttore hanno rivelato odore di salso o neutro e gli animali hanno reagito immediatamente all\u2019aspersione con sale con estroflessione del piede e movimenti attivi (Nassarius) o abbondante emissione di schiuma (Bolinus), presentando valori medi di Vibrio spp. simili, rispettivamente 5,34 log10 e 5,79 log10. Tra i lotti di Nassarius reperiti in commercio (N=17), il 47% (N=8) ha rivelato odore salso pungente o nettamente sgradevole, con reazione al sale molto scarsa o assente, presentando valori medi di Vibrio spp. pari a 6,53 log10. Tutti i campioni sono risultati negativi per E. coli, V. vulnificus e V. cholerae, ma positivi per V. alginolyticus. Un campione di Bolinus \ue8 risultato positivo per V. parahaemolyticus, con genotipo potenzialmente patogeno (ToxR+, tdh+). 4. Conclusioni I lotti di entrambe le specie reperiti alla produzione sono risultati tutti vitali, mentre il 47% dei lotti di Bolinus reperiti in commercio \ue8 risultato non conforme, in quanto composto in prevalenza o totalmente da individui morti. La mancata evidenziazione di E. coli pare giustificare il disposto del Reg. CE 558/2010. Tuttavia, i valori medi relativi a Vibrio spp. del prodotto vitale, ed ancor pi\uf9 del prodotto disvitale/morto, sono risultati superiori a quelli riscontrati nel bivalve R. philippinarum nel medesimo areale, pari a 4.69 log10. In termini di sicurezza alimentare, questa condizione di polimicrobismo in animali non filtratori necessita di ulteriori studi, sia in relazione ai target potenzialmente patogeni che in relazione ai possibili effetti del catabolismo batterico aspecifico in relazione alla produzione di amine biogene

Valutazione della vitalit\ue0 e della qualit\ue0 microbiologica del lumachino Nassarius mutabilis in fase di commercializzazione

The marine snail Nassarius mutabilis represent an important fishery resource of the Adriatic sea, with a production of about 2.000 ton/year. The requirements established by the European Legislation in force for fresh (live) marine gastropods are the same as for live bivalve molluscs. Therefore, in addition to ensuring compliance with the food safety criteria, live marine gastropods placed on the market may possess organoleptic characteristics associated with freshness and viability. Unfortunately standardized methods for this assessment are lacking, but some suggestions may be acquired by the scientific literature. Particularly it has been reported that body receding and the production of bubbles and mucus may be considered a response of gastropods to different aversive stimuli. Moreover, the lacking of data on the microbiota of marine gastropods makes it very difficult to evaluate their quality and shelf-life. The aim of the present study is to give a contribution of knowledge on the assessment of viability and the microbiological characteristics of Nassarius mutabilis at retail, with respect to E. coli, Vibrio spp., V. parahaemolyticus, V. vulnificus and V.cholerae