Effect of Frozen Storage on the Chemical, Physical and Microbiological Quality of imported Mackerel (Scomber scombrus)
The imported frozen fish Scomber scombrus (Mackerel) was evaluated for the changes of it's quality during frozen storage at -18ºC for four months and it's compliance with the Egyptian standard specifications. It was found that the protein, lipid and ash contents decreased during the storage time. Furthermore, moisture increased slightly [P ˂ 0.05] during the storage time. Microbiological examination showed a significant decrease [P ˂ 0.05] in the total bacterial count during storage period. Only in surface examination, Staphylococcus was detected in the first and the second months, being 104.70×103 and 2.74×103 (cfu/gm×103), respectively.In addition, Salmonella was detected in the first month of surface examination. E. coli and Clostridium were absent in all samples. Fourteen different bacterial isolates were isolated from all samples. Twelve isolates were isolated from staph medium and two isolates were isolated from the SS agar medium. 12 isolates were cocci and 2 isolates were long rods. All isolates were Gram positive. Two isolates were spore forming and 12 isolates were non-spore forming. Six isolates were considered as Staphylococcus sp. and another six isolates were considered as Micrococcus sp..The last two isolates were considered as Bacillus sp.