1,721,040 research outputs found
Preliminary investigation on the microbiological quality of edible marine gastropods of the Adriatic Sea, Italy.
Full text linkAccording 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
Full text linkTritia 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 feedin
Detection of Human and Fish Viruses in Marine Gastropods
Full text linkSIMPLE SUMMARY: Mollusca is one of the largest phyla in the animal kingdom that includes more than 100,000 existing species living in aquatic and terrestrial habitats. Within this phylum, marine molluscs are considered an important resource for fisheries, and gastropods represent 2% of marine molluscs fished worldwide. Similar to bivalves, gastropods are susceptible to environmental contamination, and they are able to accumulate microorganisms. However, despite their economic importance, only few studies have focused on the monitoring of viral contamination in their tissues and their possible role as carriers. In this study, the presence of human pathogenic viruses such as hepatitis A virus, but not noroviruses, different to the situation in bivalve molluscs, was found in gastropods. This finding suggests a low risk of food-borne viral infections for gastropod consumers. Furthermore, one of the most impactful pathogens for marine aquaculture, nervous necrosis virus (NNV), was detected in gastropods. However, the animal tissues examined did not show any histological changes, suggesting the absence of a pathogenic effect of NNV in the analyzed gastropods. ABSTRACT: Marine gastropods represent a major food source for higher trophic levels and an important source of animal protein for humans. Like bivalve molluscs, gastropods can accumulate several types of contaminants; however, the bioaccumulation of microorganisms, particularly viruses, has been poorly investigated in these animals. This study focused on gastropods (Tritia mutabilis, Bolinus brandaris and Rapana venosa) collected during the fishing season from 2017 to 2021 in the north-western Adriatic Sea, and on clams (Ruditapes philippinarum) harvested in the same geographical area, in order to evaluate the presence of human and fish viruses in their tissues. A virological investigation was carried out on the digestive gland using molecular methods. The presence of hepatitis A virus was detected in one sample, whereas noroviruses were not present in the investigated specimens. Regarding fish viruses, it was possible to detect the presence of nervous necrosis virus (NNV) in 26.5% of the analyzed gastropods; however, the histological examination did not show any pathological changes in the nervous tissue in both NNV-positive and -negative batches. As a whole, the investigated gastropods showed the ability to bioaccumulate viruses; however, lower contamination by human viruses compared to bivalve molluscs was pointed out, posing a minor concern to human health
Primo studio pluriennale retrospettivo sulla prevalenza di Vibrio parahaemolyticus e Vibrio vulnificus nelle vongole veraci (Ruditapes philippinarum), in relazione alle condizioni ambientali nell’area di produzione della Sacca di Goro, Italia
No full textAnalisi del Sanitary Survey 2015-2017 condotto nel Golfo della Spezia: riclassificazione delle zone di produzione di molluschi bivalvi
Full text linkIntroduzione Il consumo di molluschi bivalvi (MB) crudi o poco cotti può rappresentare un rischio per la presenza di microrganismi patogeni derivanti da contaminazione fecale. La normativa comunitaria prevede che i produttori possano raccoglierli soltanto nelle zone di produzione classificate dall’autorità competente (AC) come A, B o C in relazione al livello di contaminazione fecale, con Escherichia coli come indicatore (Reg. CE n. 853/2004 e Reg. CE n. 854/2004). Per classificare le zone di produzione l’AC deve effettuare un “sanitary survey” per valutare le fonti di inquinamento e istituire un programma rappresentativo di campionamento dei MB nella zona considerata. Oltre alla valutazione di parametri biologici, chimici e fisici cogenti, l’AC può altresì valutare parametri aggiuntivi ai fini di una completa sorveglianza sanitaria. L’AC deve inoltre programmare attività di monitoraggio, generalmente a cadenza trimestrale, per verificare se il livello di rischio sia cambiato e la zona debba essere riclassificata. Il “Centro per le scienze dell'ambiente, della pesca e dell'acquacoltura” (CEFAS) ha pubblicato nel 2017 delle Linee Guida aggiornate per l’esecuzione dei sanitary surveys. Una serie di audit effettuati su undici Stati Membri nel periodo 2011-2013 dal Food and Veterinary Office (FVO) ha tuttavia evidenziato sostanziali carenze nei sistemi di riclassificazione. Nel 2011, nessuna zona di produzione era stata ancora riclassificata in Italia. La regione Liguria ha quindi intrapreso il primo sanitary survey relativo al triennio 2012-2014 per le zone di produzione di MB del golfo della Spezia. Successivamente, è stato effettuato il sanitary survey, relativo al triennio 2015-2017. Questo studio è volto ad analizzare i dati provenienti dal report “sanitary survey 2018: riclassificazione delle zone del golfo adibite alla molluschicoltura” relativo al triennio 2015-2017, elaborato dalla Struttura Igiene degli Alimenti di Origine Animale dell’ASL 5 Spezzino. Summary Consumption of raw or insufficiently cooked bivalve molluscs can result in illness due to the presence of microorganisms, notably algal biotoxins and viral contamination arising from human faecal pollution (EFSA, 2015). As established by EU legislation, gatherers may only harvest LBM from production areas with fixed locations and boundaries that the competent authority (CA) has classified as being of class A, B or C according to the level of faecal contamination and using Escherichia coli as indicator organism (Regulation CE n. 853/2004 and Regulation CE n. 854/2004). In order to classify a production area, the CA implements a sanitary survey aimed at evaluating the sources of contamination in the catchment area and establishing a sampling programme of LBM ensuring that the results of the analysis are as representative as possible for the considered area. Ongoing monitoring (generally of a three-annual basis) are also needed to determine whether the level of risk has changed, and the classification status should be therefore modified. In 2017, the Centre for Environment Fisheries and Aquaculture Science (CEFAS) published an updated Community guide providing principles and operational guidelines that should be applied by the CA to practically perform the sanitary survey. Despite of this legislative background, a series of audits undertaken between 2011 and 2013 by the European Commission's Food and Veterinary Office (FVO) on eleven Member States highlighted consistent gaps in the classification systems of LBM production areas. According to the official data, no re-classification procedures had been performed yet in 2011 within the entire Italian territory. Given the necessity to fulfil EU requirements, the Liguria Region implemented its first sanitary survey on the production areas of the gulf of La Spezia, which covered the three years 2012-2014 and whose results were reported in a final report published in 2015. The procedures for the sanitary survey concerning the subsequent three-year period were initiated in 2015 and the relative final report was published in 2018. The aim of this study was to analyse the data from the final report of the sanitary survey concerning the three years 2015-2017 developed by ASL 5 Spezzino and published in 2018. Materiali e Metodi Sono stati estrapolati dati relativi al numero e alla tipologia di analisi effettuate sulle specie Mytilus galloprovincialis, Crassostrea gigas e Venus verrucosa nei punti di campionamento previsti dal piano di monitoraggio e al numero e alla tipologia di non conformità (NC) riscontrate sulla base di parametri cogenti e parametri aggiuntivi di sorveglianza sanitaria. I dati sono stati confrontati con quelli del sanitary survey relativo al triennio precedente (2012-2014). Opportuni test statistici sono stati utilizzati per valutare i dati provenienti dal monitoraggio di E. coli e Norovirus. Risultati e Discussione Sono state effettuate 4306 analisi, soprattutto su M. galloprovincialis (89%) e per lo più su agenti biologici e biotossine marine. Sono state rilevate 160 NC, la maggior parte delle quali (93.7%) riferibili a positività per Norovirus in M. galloprovincialis e C. gigas, con una forte prevalenza del genogruppo GII. La prevalenza di Norovirus nel golfo della Spezia è risultata essere tra le più elevate a livello nazionale. Al contrario, nonostante alcune NC riscontrate per le biotossine marine, lo stato sanitario delle zone di produzione del golfo è risultato relativamente sicuro rispetto ad altre realtà nazionali. È stato dimostrato che i livelli di E. coli sono correlati sia con la piovosità che con la stagionalità (maggiori nel periodo più freddo). In entrambi i casi sono principalmente coinvolti i punti di campionamento interni alla diga e della Baia di Portovenere, da attribuire principalmente alla direzione delle correnti marine ed al loro rallentamento nei suddetti punti. Rispetto al confronto con il triennio precedente, è stata riconfermata la classe B per M. galloprovincialis, le zone di produzione di C. gigas sono state riclassificate A e quelle di V. verrucosa sono invece state definitivamente chiuse per le difficoltà riscontrate nel reperimento di un numero di campioni rappresentativo. Il sanitary survey si è confermato uno strumento utile nella riclassificazione e nel monitoraggio sanitario delle zone di produzione di MB
Primo studio pluriennale retrospettivo sulla prevalenza di Vibrio parahaemolyticus e Vibrio vulnificus nelle vongole veraci (Ruditapes philippinarum), in relazione alle condizioni ambientali nell’area di produzione della Sacca di Goro, Italia
No full textPreliminary study on the antimicrobial susceptibility pattern related to the genotype of Vibrio vulnificus strains isolated in the north-western Adriatic Sea coastal area
Full text linkV. vulnificus is a Gram-negative bacterium, commonly found in estuarine and coastal habitats, that can infect humans through seafood consumption or wound exposure. This study represents the first attempt to correlate the genotype of Vibrio vulnificus strains isolated in the north-western Adriatic Sea coastal area, with their antimicrobial susceptibility patterns. On the whole, 40 V. vulnificus strains, isolated from shellfish (n=20), different coastal water bodies (n=19), and the blood of a Carretta carretta turtle (n=1), were utilized. All strains were positive for the species-specific genes vvhA and hsp, with high variability for other markers: 55% (22 out of 40) resulted of the environmental (E) genotype (vcgE, 16S rRNA type A, CPS2 or CPS0), 10% (4 out of 40) of the clinical (C) genotype (vcgC, 16S rRNA type B, CPS1), and 35% (14 out of 40) of the mixed (M) genotype, possessing both E and C markers. The antimicrobial susceptibility was assayed by the diffusion method on agar, according to the Clinical Laboratory Standards Institute (CLSI), utilizing the following commercial disks (Oxoid): ampicillin (AMP), ampicillin- sulbactam (SAM), piperacillin (PRL), cefazolin (KZ), cefotaxime(CTX), ceftazidime( CAZ), imipenem (IPM), meropenem (MEM), amikacin (AK), gentamicin(CN), tetracycline(TE), ciprofloxacin (CIP), levofloxacin (LEV), trimethoprim-sulfamethoxazole (SXT), and chloramphenicol (C). 75% of the strains, (n=30) including all C strains, was sensitive to all the tested antibiotics, whereas E strains showed intermediate sensitivity to AK (2 strains), CIP and CAZ (1 strain), TE (1 strain) and resistance to KZ (1 strain), and 4 M strains showed I to AK
Fecal shedding of thermophilic Campylobacter in a dairy herd producing raw milk for direct human consumption.
Full text linkFactors affecting the thermophilic Campylobacter fecal shedding in Italian dairy farming conditions have been investigated in a 12-month longitudinal study performed in a dairy farm authorized to sell raw milk in Italy. Fifty animals were randomly selected from 140 adult and young animals, and fecal sampling was performed six times at two month intervals; additionally at each sampling, three trough water samples and two trough feed samples were collected for both adult and young animals. Samples were analyzed by real-time PCR and cultural examination. Overall 33 samples (9.7%) were positive for thermophilic Campylobacter by real-time PCR: 26 out of 280 (9.2%) fecal samples, six out of 36 water points (16.6%) and one of the 24 feed samples (4.2%). Campylobacter jejuni was isolated from 6 out of 280 samples; no other Campylobacter sp. was isolated. A higher but not significant positivity was observed in fecal samples of younger animals (11.33%% versus 6.92% of adult animals) and a higher and significant positivity was observed in water samples collected from the water troughs of young animals. A distinct temporal dynamic trend was observed during the study period for both cows and calves, with two prevalence peaks between November/December and between May/July. Several factors such as calving, housing practices, herd size, management practices forcing together a higher number of animals, variations in feeding or water source, which were previously reported as cause of temporal variation in different farming conditions, could be excluded as cause of the two seasonal peaks in this study. The factors affecting the seasonality of Campylobacter shedding in the dairy herds remain unclear and warrant further investigation. The results of the present study indicate that special attention should be paid to farm hygiene management in farms authorized to produce and sell raw milk with increased surveillance by the authorities in certain periods of the year
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