Application of a systematic experimental procedure to develop a microbial model for rapid fish shelf life predictions

A systematic experimental procedure for fish shelf-life modelling was used to develop a model for predicting the quality of fish in the chill chain. F or this, the growth of the naturally occurring bacteria pseudomonads, Shewa nella putrefaciens, Enterobacteriaceae, lactic acid bacteria and yeasts, on gilt-head seabream (Sparus aurata), was studied at temperatures from 0 to 15 degrees C. The results from the microbiological, organoleptical and chem ical analysis conducted on naturally contaminated fish as well as on inocul ated sterile fish blocks identified pseudomonads as a good spoilage index. Growth of pseudomonads was modelled as a function of storage temperature an d correlated to organoleptical shelf life. To reduce the time required for the enumeration of the initial pseudomonads number, which is crucial inform ation for shelf life prediction, a conductance assay was established. Compa red with the conventional microbiological tests, this method gave results i n one-fourth of the time. (C) 2000 Elsevier Science B.V. All rights reserve d.