Novel application of an optical inspection system to determine the freshness of (mackerel) stored at a low temperature.

This study evaluated the use of an optical inspection system (OIS) to determine the freshness of mackerel (). The correlations between the light reflection intensity (LRI) of mackerel eyes (determined using an OIS) and the volatile basic nitrogen content (VBN) and K-value were analyzed. After unloading at the harbor, the mackerel were stored at 4 °C for 9 days and the VBN, K-value, and LRI were determined at 3-day intervals.