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

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+)

Detection of Human and Fish Viruses in Marine Gastropods

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

Fecal shedding of thermophilic Campylobacter in a dairy herd producing raw milk for direct human consumption.

Factors 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