Safety Assessment of Crayfish (Astacus Leptodactylus ESCH., 1823) from Microbial Load and Biogenic Amines Signature: Impact of Post-Catch Icing and Frozen Storage

In prevalent conditions, fresh-caught fish were held on ice until storage at optimal temperatures. The aim of this study was to investigate and confirm biogenic amines formation and microbiological quality of crayfish during 2 days post-catch icing and 90 days frozen storage. Of the considered biogenic amines in fresh crayfish, puterscine and cadaverine were detected and initial concentrations of them were 5.33 and 50.57 mu g/g of flesh, respectively. Psychrotrophs and cadaverine were the major bacteria and biogenic amines detected in crayfish at all sampling stages, respectively. At the end of ice storage, samples had higher biogenic amines and bacterial load when compared with fresh samples (P < 0.05). During the first 30 days of frozen storage, simultaneous with slight changes of biogenic amines, bacterial load significantly decreased (P < 0.05), but as frozen storage time lengthened, progressive development of biogenic amines and microbial load (except for Pseudomonas spp.) was observed. The best correlation was for psychrotrophic with histamine (r = 0.82). At the end of storage, although final values of bacterial load were very negligible, total BAs (487.03 mu g/g), especially histamine (110.22 mu g/g) exceeded the proposed tolerable maximum levels for total biogenic amines (300 mu g/g) and histamine (50 mu g/g). It could be concluded that crayfish can be hazardous after 60 days.