The extension of the shelf‐life of sardine which were packaged in a vacuum stored under refrigeration, and treated by δ‐irradiation

Abstract

SummarySardines (Sardina pichardus) were vacuum packaged in polyethylene bags, and irradiated at 1, 2 and 3 kGy doses in a Co‐60 δ‐irradiator. The unirradiated and irradiated samples were stored at 2 ± 1 °C. Microbiological analyses were done for total aerobic mesophiles, micrococci and staphylococci, coagulase positive staphylococci, Enterobacteriaceae, coliform bacteria, Escherichia coli, and psychrophilic bacteria. Trimethylamine‐nitrogen (TMA‐N), thiobarbituric acid (TBA) and pH values were determined. Sensory attributes were also evaluated. In the unirradiated samples, TMA‐N and pH values showed good correlations with sensory scores. There were no differences in TBA values between the irradiated samples. Based on microbiological criteria, the shelf‐life increased two to threefold compared with the control samples. These experiments demonstrate that irradiation extends the storage life of pre‐packaged sardines and that, for practical purposes, the different treatments make very little difference to the extension of shelf‐life of acceptable product.