The efficacy of depuration using UV light and chlorinated seawater for decontaminating Vibrio parahaemolyticus and Vibrio vulnificus from oysters was investigated. Oysters were contaminated with a five-strain cocktail of V. parahaemolyticus or V. vulnificus to levels of 10(4) to 10(5) CFU ml(-1) for bioaccumulation. The depuration was conducted in a closed system in which 350 liters of seawater was recirculated at a rate of 7 liters/min for 48 h at room temperature. Counts of V. parahaemolyticus or V. vulnificus were determined at 0, 6, 18, 24, and 48 h. Three treatments were conducted: T1, control treatment; T2, UV treatment; and T3, UV plus chlorine treatment. After 48 h of depuration of V. parahaemolyticus, T3 reduced the count by 3.1 log most probable number (MPN) g(-1) and T2 reduced the count by 2.4 log MPN g(-1), while T1 reduced the count by only 2.0 log MPN g(-1). After 48 h of depuration of V. vulnificus, T2 and T3 were efficient, reducing the counts by 2.5 and 2.4 log MPN g(-1), respectively, while T1 reduced the count by only 1.4 log MPN g(-1). The UV light plus chlorine treatment was more efficient for controlling V. parahaemolyticus in oysters. Both UV light and UV light plus chlorine were efficient for V. vulnificus. The present study is the first report showing the efficacy of depuration systems for decontaminating V. parahaemolyticus and V. vulnificus in oysters cultivated on the Brazilian coast. This study provides information on processes that can contribute to controlling and preventing such microorganisms in oysters and could be used for effective postharvest treatment by restaurants and small producers of oysters on the coast of Brazil.

Introduction:This research aimed to identify and quantify potentially pathogenic Vibrio from different cultivations of bivalve shellfi sh in the State of Santa Catarina, Brazil, and water regions in the South Bay, as well as correlate the incidence of these microorganisms with the physicochemical parameters of marine waters. Methods: Between October 2008 and March 2009, 60 oyster and seawater samples were collected from six regions of bivalve mollusk cultivation, and these samples were submitted for Vibrio counts. Results: Twenty-nine (48.3%) oyster samples were revealed to be contaminated with one or more Vibrio species. The Vibrio parahaemolyticus and Vibrio vulnifi cus counts in the samples ranged from < 0.5 log 10 Most Probable Number (MPN) g -1 to 2.3 log 10 MPN g -1 oyster and from < 0.5 log 10 MPN g -1 to 2.1 log 10 MPN g -1 oyster, respectively. Of the 60 seawater samples analyzed, 44 (73.3%) showed signs of contamination with one or more vibrio species. The counts of V. parahaemolyticus and V. vulnifi cus in the samples ranged from < 0.3 log 10 MPN·100mL -1 to 1.7 log 10 MPN·100mL -1 seawater and from < 0.3 log 10 MPN·100mL -1 to 2.0 log 10 MPN·100mL -1 seawater, respectively. A positive correlation between V. vulnifi cus counts and the seawater temperature as well as a negative correlation between the V. parahaemolyticus counts and salinity were observed. Conclusions:The results suggest the need to implement strategies to prevent vibrio diseases from being transmitted by the consumption of contaminated bivalve shellfi sh.

Ocurrence of Vibrio spp., positive coagulase staphylococci and enteric bacteria in oysters (Crassostrea gigas) harvested in the south bay of Santa Catarina island, Brazil IntroductionIn Brazil, bivalve mollusks production takes place mainly in Santa Catarina State, south Brazil, due to the excellent geographical conditions of this area for marine organism cultures, such as the presence of a large number of bays facilitating the establishment of mollusk farms (COELHO et al., 2003;CORRÊA et al., 2007;OLIVEIRA NETO, 2005). In 2007, about 11.000 t of mollusks were commercialized in Santa Catarina State, the largest producing region of oysters (Crassostrea gigas). The major production takes place in sea farms located in the South Bay of Santa Catarina Island (OLIVEIRA NETO, 2007).Oysters are filter-feeders that efficiently concentrate microorganisms from polluted habitats, and because they are often consumed raw, they pose a health risk to consumers (CORRÊA et al., 2007;LALOO et al., 2000; PEREIRA et al., 2006;SILVA et al., 2004). The enteric bacteria, originating from the contamination of water with human residues, can readily contaminate the fauna in marine environments, especially molluscan shellfish (CORRÊA et al., 2007, PEREIRA et al., 2006. To guarantee sanitary quality, mollusk cultures should be monitored for contamination by pathogenic microorganisms (CORRÊA et al., 2007).Vibrios are very common in marine and estuarine water environments and some may cause infections in humans that were exposed to seafood or sea water. Several Vibrio species are pathogenic to humans and may be present in raw or partially cooked shellfish (LHAFI; KÜHNE, 2007; PEREIRA et al., 2007a, b , para ambos os microrganismos, sugerindo um monitoramento tanto destas espécies quanto da temperatura das águas marinhas nas regiões de cultivo. Com base nos resultados das análises microbiológicas, as amostras analisadas mostraram qualidade bacteriológica aceitável, ou seja, dentro dos parâmetros estabelecidos na legislação brasileira. Palavras-chave: qualidade microbiológica; moluscos bivalves; filtradores; Escherichia coli; Vibrio parahaemolyticus; Vibrio vulnificus. AbstractThe aim of this study was to assess the contamination of oysters (Crassostrea gigas), harvested in six different regions of the South Bay of Santa Catarina Island, with Coliforms at 45 °C, Escherichia coli, Vibrio spp., positive coagulase staphylococci, and Salmonella sp. over a period of one year. One hundred eighty oyster samples were collected directly from their culture sites and analyzed. Each sample consisted of a pool of 12 oysters. All of the samples analyzed showed absence of Salmonella, 18 (10%) samples showed presence of Escherichia coli, 15 (8.3%) samples were positive for V. alginolyticus, and Vibrio cholerae was detected in 4 samples (2.2%). The counts of positive-coagulase staphylococci varied from <10 to 1.9 × 10 2 CFU.g , for both microorganisms. This suggests the need for monitoring these vibrios contamination in oysters. Based on the results of the ...

The immunomagnetic separation (IMS) is a technique that has been used to increase sensitivity and specificity and to decrease the time required for detection of Salmonella in foods through different methodologies. In this work we report on the development of a method for detection of Salmonella in chicken cuts using in house antibody-sensitized microspheres associated to conventional plating in selective agar (IMS-plating). First, protein A-coated microspheres were sensitized with polyclonal antibodies against lipopolysacharide and flagella from salmonellae and used to standardize a procedure for capturing Salmonella Enteritidis from pure cultures and detection in selective agar. Subsequently, samples of chicken meat experimentally contaminated with S. Enteritidis were analyzed immediately after contamination and after 24h of refrigeration using three enrichment protocols. The detection limit of the IMS-plating procedure after standardization with pure culture was about 2x10 CFU/mL. The protocol using non-selective enrichment for 6-8h, selective enrichment for 16-18h and a post-enrichment for 4h gave the best results of S. Enteritidis detection by IMS-plating in experimentally contaminated meat. IMSplating using this protocol was compared to the standard culture method for salmonellae detection in naturally contaminated chicken cuts and yielded 100% sensitivity and 94% specificity. The method developed using in house prepared magnetic microespheres for IMS and plating in selective agar was able to diminish by at least one day the time required for detection of Salmonella in chicken products by the conventional culture method.

No abstract

Anomalocardia brasiliana is an intertidal filter-feeding clam that can accumulate enterobacteria, such as Escherichia coli, and consequently affect human health. Shellfish depuration is a procedure which reduces microbiological contaminants; however, salinity and depuration time can vary across species to adequately reduce bacteria load. To analyze the effect of salinity on the bioaccumulation and depuration of E. coli by A. brasiliana, this study evaluated salinity and depuration time in animals artificially contaminated with E. coli. Each experimental group of clams were acclimated for 6 hours in a recirculating aquaculture system (RAS) and then exposed to E. coli for 18 hours. Following exposure, clams were then held at one of four salinities (35, 30, 25 e 20) for a period of one of four depuration times (0, 12, 24, 36 and 48h). The highest bioaccumulation of E. coli in A. brasiliana was observed in clams held at salinities of 35, 30 and 25. The greatest reduction of E. coli in A. brasiliana was observed in clams held at 25 for 48 hours. A salinity of 20 showed low bioaccumulation and depuration of E. coli. The results of this study will contribute to developing a protocol for depurating A. brasiliana to mitigate human health concerns.

No abstract

Modo de acesso: World Wide Web Inclui bibliografia 1. Tecnologia de Alimentos 2. Alimentos 3. Nutrição I. Título CDD-664.005 O conteúdo dos artigos e seus dados em sua forma correção e confiabilidade são de responsabilidade exclusiva dos seus respectivos autores.