Residual potassium sorbate level effective to control fungi in dried salted fish at tropical ambient temperature

Abstract

The use of sorbic acid and sorbate are permitted in all countries for preservation of fish and fishery products as effective
inhibitors of fungi. The dipping in 0.2 % potassium sorbate solution for 2 h was found to be sufficient for silver pomfret,
goat fish and rainbow sardine to maintain residual sorbate level close to the accepted permissible limit of 1000 ppm in
muscle (moisture level of 23 %). Jew fish and thread fin trevally required slightly longer dipping time to retain the same
sorbate level because of thick skin. During storage at ambient temperature (28 ± 5 0C) with RH 80 ± 15 %, the sorbate level
in dried rainbow sardine and trevally decreased rapidly to below 200 ppm in 6 months and visible fungal colonies appeared
on these samples during the same period. Dried fish samples of jew fish with lowest residual sorbate level i.e., 420 ppm,
could retain sorbate ion above 200 ppm and was free from visible fungal growth for 6 months. Residual sorbate level of
above 200 ppm in the muscle of dried fish samples was found necessary to inhibit/delay the fungal growth during storage