P. Dalgaard et al., SPOILAGE AND SHELF-LIFE OF COD FILLETS PACKED IN VACUUM OR MODIFIED ATMOSPHERES, International journal of food microbiology, 19(4), 1993, pp. 283-294
Microbial growth, sensory and chemical changes and composition of gas
atmosphere were studied in vacuum packed (VP) and modified atmosphere
packed (MAP) cod fillets stored at 0-degrees-C. Contrary to previous s
tudies, coccobacilli and pleomorphic Gram-negative microorganisms (2-4
by 2-5 mum) and not Shewanella putrefaciens were found most likely to
be the main spoilage organisms. These microorganisms, which may be Ph
otobacterium phosphoreum, can explain the short shelf-life extension o
f VP and MAP fish products compared to meat products. It is suggested
that they may inhibit the typical H2S-producing fish spoilage bacteria
, S. putrefaciens, as the maximum concentration of H2S-producing bacte
ria found in MAP fish products is wery low. Compared to VP, a shelf-li
fe extension of 6-7 days was obtained with 48% CO2 in MAP. However, wi
th pure CO2 the shelf life was only extended by 2-3 days. Poor texture
and high drip loss indicated that the shelf life of these fillets was
limited by chemical reactions and not only by microbial activity.