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Vibrio is a very diverse genus that is responsible for different human and animal diseases. The accurate identification of Vibrio at the species level is important to assess the risks related to public health and diseases caused by aquatic organisms. The ecology of Vibrio spp., together with their genetic background, represents an important key for species discrimination and evolution. Thus, analyses of population structure and ecology association are necessary for reliable characterization of bacteria and to investigate whether bacterial species are going through adaptation processes. In this study, a population of Vibrionaceae was isolated from shellfish of the Venice lagoon and analyzed in depth to study its structure and distribution in the environment. A multilocus sequence analysis (MLSA) was developed on the basis of four housekeeping genes. Both molecular and biochemical approaches were used for species characterization, and the results were compared to assess the consistency of the two methods. In addition, strain ecology and the association between genetic information and environment were investigated through statistical models. The phylogenetic and population analyses achieved good species clustering, while biochemical identification was demonstrated to be imprecise. In addition, this study provided a fine-scale overview of the distribution of Vibrio spp. in the Venice lagoon, and the results highlighted a preferential association of the species toward specific ecological variables. These findings support the use of MLSA for taxonomic studies and demonstrate the need to consider environmental information to obtain broader and more accurate bacterial characterization. Vibrio spp. are Gram-negative halophilic bacteria belonging to the class Gammaproteobacteria. Vibrio is one of the most studied and diverse genera of microorganisms found in aquatic ecosystems and comprises the major culturable bacteria in marine and estuarine environments (1). According to the Association of Vibrio Biologists (AViB; http://www2.ioc.fiocruz.br/vibrio/AVib /species.html), there are 99 accepted or proposed Vibrio species, although the recent description of new species has led to a constantly changing taxonomy. Vibrio spp. are frequently isolated from fish, fish products, and edible shellfish, and a large number of species are pathogenic to different hosts. Some species, such as V. cholerae, V. parahaemolyticus, and V. vulnificus, cause serious food-borne gastroenteritis in humans. Other species, such as V. anguillarum and V. salmonicida, are pathogenic for fish; V. splendidus-related species are pathogenic for bivalves, and V. harveyi and V. campbellii are pathogenic for shrimps (1, 2, 3). Recently, Austin suggested a classification of zoonotic Vibrio in two classes named "higher-risk" vibrios (V. cholerae, V. parahaemolyticus, and V. vulnificus) and "lower-risk" vibrios (V. alginolyticus, V. fluvialis, V. furnissii, V. harveyi, and V. mimicus) (4). Bivalve mollusks such as clams and mussels represent products of great econ...

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Vegetables are an important source of nutrients, but they can host a large microbial population, particularly bacteria. Foodborne pathogens can contaminate raw vegetables at any stage of their production process with a potential for human infection. Appropriate washing can mitigate the risk of foodborne illness consequent to vegetable consumption by reducing pathogen levels, but few data are available to assess the efficacy of different practices. In the present work, six different washing methods, in the presence or absence of sanitisers (peracetic acid and percitric acid, sodium bicarbonate, sodium hypochlorite) and vinegar, were tested for their effectiveness in reducing Salmonella and Listeria counts after artificial contamination of raw rocket (Eruca vesicaria). Results showed that washing with sodium hypochlorite (200 mg/L) was the only method able to produce a significant 2 Log reduction of Salmonella counts, but only in the case of high initial contamination (7 Log CFU/g), suggesting potential harmful effects for consumers could occur. In the case of Listeria monocytogenes, all the examined washing methods were effective, with 200 mg/L sodium hypochlorite solution and a solution of peracetic and percitric acids displaying the best performances (2 and 1.5 Log reductions, respectively). This highlights the importance of targeting consumers on fit for purpose and safe washing practices to circumvent vegetable contamination by foodborne pathogens.