Recuperação de cepas de Vibrio parahaemolyticus inoculadas no camarão Litopenaeus vannamei, submetido às temperaturas de resfriamento e congelamento

Abstract

The aim of this study was to evaluate the survival of Vibrio parahaemolitycus inoculated in shrimp Litopenaeus vannamei at different temperatures of refrigeration (refrigerator, freezer and isothermic box with ice) during ten days and on the 15th, 20th and 25th days. The experiment was repeated six times from October, 2005 to March, 2006. Shrimps were obtained on a fish market located at Praia do Mucuripe, Fortaleza, Ceará. In the laboratory, the shrimps were washed with distilled water and immersed in boiling water for five minutes in order to eliminate any other Vibrio species in the sample. The inoculation happened with the contact between the shrimps and the V. parahaemolyticus culture for five minutes. Then, the sample was divided in forty 25-g portions, one of which was used as initial time. The other 39 portions were separated in three batches maintained on freezer (-21°C), refrigerator (11°C) and isothermic box with ice (-1°C to 13°C). The number of V. parahaemolyticus was monitored for 10 days and on 15th, 20th and 25th days by the plate count method on TCBS and PCA media. All temperatures were efficient to control the viable cells of V. parahaemolyticus. The action of cold produced by ice, refrigerator and freezer inhibit the bacterial growth on shrimps. The freezer was the most efficient treatment in reducing the action of V. parahaemolyticus on the shrimp L. vannamei.