Effect of psychrophilic bacteria to estimate fish quality

Growth of psychrophilic microorganisms in chilled seafoods is important but they have limited use in shelf-life studies because there is not an acceptability limit. In this study, pH, total volatile bases nitrogen (TVB-N), trimethylamine nitrogen (TMA-N), total mesophilic and psychrophilic aerobic bacteria analyses were used to estimate the shelf life of cold stored (+4 +/- 1C) fish. Shelf life of horse mackerel was determined as 1 day, while cod and anchovy spoiled on the second day, and rainbow trout spoiled on the third day of storage. Total mesophilic aerobic bacteria counts did not indicate the spoilage remaining lower than the acceptability limit; but psychrophilic aerobic bacteria counts were around 6 log cfu/g, when the samples spoiled. It was determined that, estimation of the psychrophilic microorganisms gives better results to the shelf-life estimation of chilled fish than mesophilic bacteria and 6 log cfu/g could be accepted as the acceptability limit.