Alterações sensorial, microbiológica e físico-química de Camarões (Litopenaeus Vannamei) inteiros e processados armazenados em gelo

Abstract

Shrimp is a highly perishable food when compared to other animal protein sources. Therefore, to delay or start the degradation process and guarantee the quality of the fish, some procedures are adopted, such as evisceration and ice cooling. The quality of the fish can be assessed through sensory, microbiological and physical chemical parameters, together with information on the product's useful life and safety for the consumer. These parameters presented are pros and cons and may or may not have relations between them. Seeking to improve the procedures for monitoring refrigerated shrimp, the objective was to evaluate the quality of the shrimp, the different processes and kept under refrigeration through sensory, microbiological and physical-chemical analyzes, to identify the influence of the ice microbiota and to use the succession of cultivable bacterial groups throughout the storage period. Two experiments were carried out, the first in March 2019 and the second in October 2019, dividing the groups into groups according to the pretreatment treatment and the following groups: whole groups (T1), headed and eviscerated groups (T2) and groups shelled, headed and gutted (T3). The shrimps analyzed for sensory aspects by the method of quality index (MIQ), microbiological with counters of viable mesophilic bacteria (CBVm) and psychrophilic (CBVp) and pH determination were kept refrigerated at 2 ºC for 20 days. The sensory analysis showed that the T1 prawns show a shorter shelf life than the other two used in the two experiments. The quantity of CBVm and CBVp was similar with stable counters up to 14th day and accelerated growth thereafter with surplus values of 106 for CBVm and 107 for CBVp in the first experiment. The second experiment shows low counts, in all movements, until the 12th day for mesophiles and 8th for psychrophils and a surplus of 107 for CBVm and 108 for CBVp up to 20 days. T2 showed a higher bacterial load at the end of the experiment in both experiments. Although Brazilian legislation does not establish a maximum limit for mesophilic bacteria, the ICMSF (ICMSF, 1986) recommends that this number should not exceed 107 CFU/g. The predominant cultivable bacteria at the end of the 20 days belonged to the genera Bacillus, Pseudomonas, Aeromonas and Vibrio, involved in the degradation of marine fish. The Quality Index Method (QIM) proved to be an effective tool for analyzing quality of shrimp kept on ice, however, it must be adapted to the type of processing applied to the product prior to cooling.