Lactic Acid Dipping for Inhibiting Microbial Spoilage of Refrigerated Catfish Fillet Pieces

Subdivided catfish fillets were dipped in chilled (7°C) solutions of 1.70% and 2.55% (v/v) lactic acid (LA) for 10 min. Control pieces were not dipped. All pieces were individually placed in sterile plastic bags and stored either at 7°C for 3 days or on ice in a 2°C cold room for 6 days. Aerobic plate count (APC) was periodically determined using plate count agar pour plate and Petrifilm™ film methods. At 7°C, APC for both LA treatments was significantly (P<0.05) lower than for controls during 3 days of storage. Day 3 APC values for 1.70% and 2.55% LA samples were lower than controls by 1.3 and 2.3 logs, respectively. Similarly, after 6 days at 2°C the APC values for 1.70% and 2.55% LA samples were 1.3 and 3.1 logs lower, respectively, than for control samples. Throughout storage at both temperatures, 2.55% LA samples had significantly (P<0.05) lower APC than 1.70% LA samples. No significant (P<0.05) difference was observed between pour plate and Petrifilm™ APC methods, although APC values for the latter method were consistently slightly higher. Untrained sensory evaluation panelists could not consistently distinguish between control and 1.70% LA catfish pieces that were dipped in batter, breaded, and fried. Control, 1.70% LA, and 2.55% LA‐dipped pieces were not rated as significantly different (P<0.05) in whiteness of flesh, tartness, and overall flavor acceptability. Acid dipping of catfish could be useful for extending the refrigerated shelf‐life of unfrozen catfish fillets.