Characterization of the spoilage heterogeneity of Aeromonas isolated from chilled chicken meat: in vitro and in situ

Bacteria are the primary determinant in spoilage of chilled meat. The Aeromonas genus has been discovered to be involved in the dynamics of meat spoilage, but its related knowledge was quite limited. In this study, twelve isolates of Aeromonas isolated from chilled chicken were tested to characterize the heterogeneity and strength of spoilage in vitro and in situ. The results showed that spoilage ability of Aeromonas was isolate-dependent, with heterogeneity in obvious profiles. Isolates of number 25, 27, 29, J3-1 and J3-2 displayed larger decomposition zone diameters on Raw-chicken juice agar (RJA) plates, and their extracellular enzymes also showed stronger protein degradation ability analyzed by SDS-PAGE, whereas isolates of number 13 and 57 showed quite weak degradation ability. For evaluation of spoilage ability in situ, the TVC, TVBN, pH and YTVBN/CFU values of the chilled chicken inoculated with A. salmonicida 29 were higher than that of A. salmonicida 57, meanwhile the sensory scores were lower than that of A. salmonicida 57. These results suggested that isolate-by-isolate should be considered when evaluating the spoilage ability of dominant microorganisms. The findings will provide a primary basis for further mechanisms exploration of Aeromonas spoilage and aid in developing innovative preservation of chilled chicken.