Use of eye fluid refractive index in sardine (Sardina pilchardus) as a freshness indicator

In this study the usage of eye fluid refractive index as a freshness indicator for sardine (Sardina pilchardus) was investigated. Eye fluid refractive index measurements and quality control analyses of sardine during storage at 0degreesC and +4degreesC were performed at 24h intervals. According to the sensory analysis results, the sardines stored at 0degreesC and +4degreesC had a shelf life of 6 and 4days, respectively. The changes in eye fluid refractive index values during storage at 0degreesC were not significant while the changes at +4degreesC were significant (p<0.01). TVB-N and TMA-N values significantly (p<0.01) increased. No microbiological growth was observed at 0degreesC, however the increase in microorganism counts was significant at +4degreesC. As a result, eye fluid refractive index measurements can be used as a quality criterion for sardine freshness, when stored at +4degreesC.