INFLUENCE OF PROCESSING SCHEMES ON INDICATIVE BACTERIA AND QUALITY OFFRESH AQUACULTURED CATFISH FILLETS

Fresh aquacultured catfish fillets were obtained from three processors using different processing protocols in summer, autumn, winter, and s pring and evaluated for microbial quality. Twenty freshly processed fi llets were randomly selected and each fillet was placed in a sterile p olyethylene bag. The fillets were transported on ice-pack overnight by air immediately after processing. Five fillets were randomly selected for microbial assays. Each fillet was weighed and an equal volume of sterile 0.1% peptone water at 0 to 1 degrees C was added aseptically. The fillet was massaged (or rinsed) for 120 s and the rinse was used t o determine microbial quality. Aerobes (incubation at 35 degrees C for 48 h) and psychrotrophs (incubation at 20 degrees C for 96 h) were en umerated using 3M Petrifilm(TM) Aerobic Count plates. Escherichia coli (incubation at 35 degrees C for 24 to 48 h) and total coliforms (incu bation at 35 degrees C for 24 to 48 h) were enumerated on 3M Petrifilm (TM) E. coli Count plates. Staphylococcus aureus counts were determine d on Baird-Parker agar (incubation at 35 degrees C for 48 h). Signific ant differences (P less than or equal to 0.05) in aerobic, psychrotrop hic, total coliform, E. coli, and S. aureus counts due to temperature effects during production and variations in processing protocols were observed. E. coli and S. aureus counts were significantly different du ring the four seasons. E. coli and S. aureus counts were high during s ummer and low during winter weather There was a significant difference (P less than or equal to 0.05) in aerobic, psychrotrophic, and total c oliform counts among the three processors during warm weather; however , these differences were significantly (P less than or equal to 0.05) reduced in cold weather.