Avaliação microbiológica e físico-química de vôngole (Anomalocardia brasiliana) e siri (Família Portunidae) embalados em diferentes atmosferas e armazenados sob refrigeração e congelamento

Abstract

The bivalve molluscs and crustaceans are found throughout almost the entire brazilian coast and are used in the composition of various dishes of regional cuisine. The Baía de Todos os Santos is one of the largest clusters of Bahia extraction of seafood, but the shellfishers of the region use very rudimentary techniques to process this type of food, therefore, most know the basic concepts of Good Manufacturing Practices. The meat of seafood is highly perishable and can transmit microorganisms with pathogenic potential, if there is poor hygiene in their steps of procedure. However, the risks that people face when using this type of food depends not only of the application of proper hygienic techniques during their processing and application of cold during their storage. The type of seafood eaten, the season and quality of estuarine waters where they were collected also influence directly the quality of the final product. This research evaluated the quality of clams (Anomalocardia brasiliana) and the Family Portunidae crabs processed in the Jaguaripe’s districts of Mutá, Pirajuía and Ourives and the municipality of Salinas da Margarida, all located around the Baía de Todos os Santos. Was monitored each step of the processing of seafood through the registration of time and temperature and the presence of Escherichia coli and S. aureus on the surface of utensils and hands of shellfishers. Then aliquots in put individual packages of were 250 grams in packages without vaccuum and vacuum samples of shellfish after processing. Part of the seafood was chilled (7°C) and another part was frozen (-18°C). The shelf life of the product was evaluated by successive analysis of microbiological and physico-chemical performed with 0, 3, 6, 9 and 12 days of storage for the chilled seafood and 0, 1, 2, 3, 4, 5 and 6 months for frozen seafood. The microbiological tests were composed of counts of mesophilic aerobic microorganisms and facultative anaerobes, microorganisms psichrophilic total, molds and yeasts, sulphite reducing clostridia, S. aureus, thermotolerant coliforms with identification of E. coli and Salmonella spp search for frozen seafood conducted according to methodology proposed by the American Public Health Association. For chilled seafood, were counting the same microorganisms in addition to determining the most probable number of Vibrio parahaemolyticus. Were analyzed for physico-chemical of pH and Eber’s reactions for H2S and ammonia. To correlate the time of storage with the pH and microbiological parameters were linear regressions. The stages of processing of seafood are sampling/capture, washing, cooking, collecting and storage under refrigeration. During cooking, the temperature of seafood exceeded 98°C for a median time of 15 minutes for clams and nine minutes for the crab. During the harvest and the collecting clams, 30% and 50% of shellfishers, respectively, were contaminated by the hands of the surface S. aureus, while during the collecting crab, 60% of the shellfishers of the area were contaminated by the bacteria from the hands. The tools used to contain seafood after collecting showed presence of 8 S. aureus in 30% to clams and 40% for crabs. 20% and 40% of the hands of the shellfishers were contaminated by E. coli during the harvest and the clams collecting respectively. 20% of the utensils used for processing the clams were also contaminated by the bacteria. Was not found E. coli on the hands and utensils of shellfishers in the processing of crab. Was not isolated V. parahaemolyticus and Salmonella in two seafood analyzed. Samples of crabs also showed no contamination with thermotolerant coliforms, E. coli and sulphite reducing clostridia. However, we for the found counts of mesophilic microorganisms of up to 9.19 LogUFCg-1 for the refrigerated clams and 8.88 LogUFCg-1 for the samples of crab chilled. The microorganisms psichrophilic reached values up to 8.24 LogUFCg-1 the refrigerated clams and 10.17 LogUFCg-1 for the refrigerated crab. Yeasts and molds were affected by low temperatures and the vacuum oscillated around of 3 LogUFCg-1 for both seafood. The S. aureus reached maximum value the 5.31 LogUFCg-1 for refrigerated clams and 7 LogUFCg-1 in the cold crab. The clams showed contamination by thermotolerant coliforms up to 3.54 LogUFCg-1 and 2.11 LogUFCg-1 for sulphite reducing clostridia. How the physical-chemical tests, tests for ammonia and H2S were not good parameters for evaluating the useful life of the crab showing positive at zero for the samples chilled and frozen in two types of packaging. However, it was effective for samples of clams showing positive result for the clams refrigerated within two types of atmosphere with only six days of storage. In clams frozen, the test for ammonia revealed the deterioration process with three months of storage, while the H2S test took six months. As the pH, the clams reached the lowest value (6.18) with three days of refrigerated storage for samples in a package with air. For the crab, the highest (8.65) was achieved with nine days of storage for samples chilled in a package with air. The freezing has proved to be the best form of storage because the extended life of the seafood for five months, while the seafood under refrigeration had life of six days. The application of vacuum was not advantage for samples packaged with air. Better hygiene hand of shellfishers and utensils used during the collecting of seafood is important to significantly reduce the contamination of meat processed by S. aureus and E. coli and probably increase the shelf life of them. Keywords: refrigerated, frozen, clams, crab, hygiene and deterioration.