The quality of frozen African sharptooth catfish (Clarias gariepinus) fillets under long-term storage conditions

The quality of frozen catfish fillets was monitored over a period of 11 mon ths at -20 degreesC, in two types of packaging materials, namely vacuum pac kaging (VP) and oxygen-permeable packaging (OPP). Representative samples (n = 5) from both types of packaging materials were drawn at random, monthly for the full period of the trial. Samples were pooled and analysed microbio logically using standard methods. Fatty acid analyses of total lipids, neut ral lipid: glycolipid and phospholipid fractions as well as sensory evaluat ion were also conducted every 3 months on the pooled samples. These tests w ere conducted to determine whether OPP (cheaper option) could be used inste ad of VP for long-term superchilling of catfish without detracting from its quality. Low microbiological counts were maintained throughout the trial, ie 4.1 x 10(4) cfug(-1) (VP) and 8.9 x 10(4) cfug(-1) (OPP) in the 11th mon th for aerobic plate count. Ne significant human pathogens were isolated, w ith the exception of Aeromonas hydrophilia (Stanier). Lipid oxidation, irre spective of packaging, showed no fixed trends during the 11 months of inves tigation. Also, no significant deviation from sensory characteristics was n oted. These results indicate that storing catfish fillets in OPP is a feasi ble and cheaper option for longterm freezing. (C) 2001 Society of Chemical industry.