Effects of temperature and salt on the shelf quality of cured Chrysichthys nigrodigitatus

The effects of different drying temperatures (60oC, 75oC, 90oC, 105oC, 120oC) and salting, on the preservation and shelf life of smoked Chrysichthys nigrodigitatus caught from the upper reaches of the Cross River was studied. Freshly caught fishes with weight ranges of 150-230g were randomly sorted into two batches, gutted and washed. One batch was salted (360gNaCl/l) and the other batch was unsalted. All the fishes in the batches were cold smoked at the same level. Some representatives of the two batches were oven dried at the selected temperatures for 4 hours. Weight changes and microbial growth was monitored on the stored finished fish products. Organoleptic and microbial results show that temperature (90oC optimum) was the most critical factor for fish preservation and longer shelf life. Salting had no significant advantage on fish preservation (P>0.05). The highest total viable count (TVC) of 1.2 x 108 cells of bacteria/g and mould growth was found on the unsalted fish and the least TVC of 1.0 x 106 cells of bacteria/g was found on the salted fish. A “best before period” of 12 days for consumption was suggested for the fish so preserved. KEY WORDS: Temperature, Salting, Chrysichthys nigrodigitatus, microbial growth, shelf life. Global Jnl Pure and Applied Sciences Vol.10(4) 2004: 501-50