OBSERVATIONS AND EXPERIMENTS ON EXTENDING SHELF-LIFE OF ROCKFISH (SEBASTES SPP) PRODUCTS WITH OZONE

On a fishing vessel and in the laboratory, trials were undertaken to s tudy the effect of ozonation on rockfish bacteria (Sebastes spp.) duri ng transport from fishing grounds. At the beginning of the experiment, bacterial loads were the same on ozone-treated and control samples. F ish transported in ozonated water Lost some of their bacterial film wi th surface slime when they were pumped from the boat's hold into the p rocessing plant. Ozonation appears to encourage the detachment of the surface slime and bacterial film by partly oxidizing the excess slime excreted during capture. When ozonated intermittently during transport the fish shelf-life was extended by about 36 h. The same ozonation tr eatment was simulated in the laboratory which revealed higher bacteria l counts on the ozonated fish than on the control samples. Fish used i n this trial are believed to-have been stored for several days prior t o ozonation. This storage may have resulted in changes in the properti es of the surface slime, counteracting the effect of ozonation.