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.

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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.

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The development of alternative microbiological techniques is driven by the necessity to meet the current needs to deliver rapid results in the manufacturing process of foods, but it is important that these methods be evaluated for each application. The objective of the present study was to assess the Petrifilm™ EB and the TEMPO® EB systems with ISO 21528-2:2004 for the count of Enterobacteriaceae in pasteurized and UHT milk samples. We analyzed the microflora of 141 pasteurized milk samples, 15 samples of artificially contaminated pasteurized milk and 15 samples of artificially contaminated UHT milk. Investigation of the method Petrifilm™ EB and ISO 21528:2 regression analysis showed a high correlation in the samples, r = 0.90 for the microflora of pasteurized milk, r = 0.98 for artificially contaminated pasteurized milk and r = 0.99 for the artificially contaminated UHT milk. In evaluating the system TEMPO EB ® method and ISO 21528:2 correlation was also significant in the analyzed samples, with r = 0.86 for the microflora of pasteurized milk, r = 0.96 for artificially contaminated pasteurized milk and r = 0.99 for artificially contaminated UHT milk. No statistically significant differences were observed between the three methods conducted to analyze artificially contaminated pasteurized and UHT milk at three inoculum levels. In conclusion, the Petrifilm™ EB system and the TEMPO® EB system may be an alternative to the ISO 21528-2:2004 for the Enterobacteriaceae assay for milk as because of the ease-of-operation and the time reduction achieved for conducting the microbiological assay using these systems.