EFFECT OF COLD SMOKING AND STORAGE TEMPERATURES ON LISTERIA-MONOCYTOGENES IN INOCULATED COD FILLETS (GADUS-MORHUS)

Experiments were conducted to study the effects of the cold smoking process and storage on Listeria monocytogenes inoculated onto cod fillets. In three trials, cod fillets were surface inoculated with L. monocytogenes, cold smoked, vacuum-packaged, and stored at 4-degrees-C for 3 weeks or at -20-degrees-C for 3 months. Samples were removed at each stage of the smoking process and during storage, and Listeria were enumerated using the three-tube most probable number MPN method. The initial inoculation concentrations were 10(5) MPN/g in trial 1, 10(6) MPN/g in trial 2, and 10(1) in trial 3. Numbers or the organism remained relatively stable during the smoking process, increased with storage at 4-degrees-C, but decreased in cell number with storage at 20-degrees-C. Substantial growth occurred in trials 1 and 2, but was very slow in trial 3 where the inoculum level was low. Hence, L. monocytogenes contamination in smoked seafoods which are not cooked prior to consumption, may pose a health risk to the consumer.