EFFECTS OF SALT AND STORAGE-TEMPERATURE ON CHEMICAL, MICROBIOLOGICAL AND SENSORY CHANGES IN COLD-SMOKED SALMON

Chemical, microbiological and sensory changes during storage of vacuum -packed cold-smoked salmon were studied using a factorial experimental design with two storage temperatures (5 and 10 degrees C) and two sal t levels (2.2 and 4.6%). The spoilage characteristics were typical of microbiological activity in all treatments, but there was no relation between sensory changes and any of the microbiological numbers (total viable counts, total psychrotrophes, lactic acid bacteria or Enterobac teriaceae). Total viable counts typically reached 10(8) cfu/g weeks be fore sensory rejection. Acetic acid, hypoxanthine, trimethylamine and ethanol concentrations increased with storage time in all treatments. The increase in ethanol depended on salt concentration but not storage temperature. Absolute values of trimethylamine ranged from 2-8 mg TMA -N/100 g initially, to 10 mg TMA-N/100 g at sensory rejection. Acetic acid levels increased with temperature and decreased with salt concent ration, but varied between 12-23 mu mol/g at rejection. Initial concen trations of hypoxanthine increased from 2-3 mu mol/g to maximum 8-9 mu mol/g, with values of 5-7 mu mol/g indicating the limit of sensory ac ceptability. Hypoxanthine was considered to be the best objective indi cator for sensory quality of cold-smoked salmon.