Abstract:In this study, the effects of three cleaning pretreatment methods for Procambarus clarkii (cleaning agent, CA; ultrasonic cleaning, UL; cleaning agent with ultrasonic cleaning, CA+UL; control group, CK) on the bacterial community and physicochemical properties of the flesh of Procambarus clarkii were investigated. The changes in the total numbers of bacteria, pseudomonas, yeast, thermophilic bacteria, psychrotrophic bacteria, pH, texture characteristics and flavor substances of crayfish meat before and after cleaning were examined. The results showed that the CA+UL treatment had the greatest bacteriostatic effect, and the total number of bacteria decreased by 1.12 lg CFU/g after cleaning, and also exhibited good bacteriostatic effects on mold yeast, sulfide-producing bacteria and thermophilic bacteria (decreased by 0.66 lg CFU/g, 0.9 lg CFU/g and 0.82 lg CFU/g, respectively). However, the effects of CA and UL treatments on the reduction of bacteria such as mold and thermophilic bacteria were not obvious, and the pH of shrimp flesh increased after cleaning. The pH of the CA+UL group underwent minimal change, with the overall quality of shrimp flesh decreased slightly after cleaning. Different cleaning methods also affected greatly the volatile substances, causing the production of n-methyl isopropyl amine and other bad smell substances. Therefore, considering the results of bacterial community and physicochemical properties of shrimp flesh, the combined use of ultrasonic and cleaning agent is more desirable.
