Changes in the Microflora of Vacuum-packaged, Irradiated Petrale Sole (Eopsetta jordani) Fillets Stored at 0.5 C

Abstract

The microfloral changes of irradiated petrale sole fillets during anaerobic (vacuum-packed in cans) refrigerated storage was determined by the identification of 1,260 microbial isolates to the generic level. The samples were irradiated at 0.0, 0.1, 0.2, 0.3, and 0.4 Mrad from a cobalt-60 gamma source, stored at 0.5 C, and examined periodically for spoilage and total microbial population and composition. The preirradiation flora consisted of Achromobacter, Micrococcus, Pseudomonas, coryneforms, Lactobacillus, and Flavobacterium. Immediately after irradiation, Micrococcus, Achromobacter, coryneforms, and Bacillus were predominant. After storage under vacuum, the spoilage flora of the nonirradiated petrale sole was predominantly Pseudomonas; the spoilage flora of the 0.1-Mrad irradiated samples consisted of Pseudomonas and Lactobacillus; and that of the 0.2-, 0.3-, and 0.4-Mrad samples was almost entirely Lactobacillus.