Histamine Formation During Salting of Spanish Mackerel (Scomberomorus commerson)

The fresh gutted Spanish mackerel were used as raw material for salting by using ratios of fish to salt as follows: 1:1, 2:1 and 3:1 by weight. Histamine content, salt content, moisture, pH, water activity (Aw), total viable count (TVC) and histamine forming bacteria (HFB) were determined at 0, 2, 6, 7, 10 and 13 days after the salting process. The salt content increased to 19% on the 13th day and became steady through the process in all treatments. There was no significant difference in the salt content among treatments. Moisture and Aw changed inversely to salt content. The pH of all samples were 5.9-6.3 during salting. However, the histamine increased from 1.87 mg/100 g to 115.52, 158.28 and 125.10 mg/100 g on the 6th day of salting in samples with a fish to salt ratio of 1:1, 2:1 and 3:1, respectively. After 6 days, it decreased markedly in all samples until the end of the process. The highest number of TVC and HFB at both 20°C and 37°C were observed in the samples with the highest histamine content on the 6th day of salting and then decreased until the end.