Whole (deheaded and eviscerated) channel catfish were dipped in 1 or 2% lactic acid or sodium percarbonate (Pergenox ®). Whole and fillets were also washed with high‐pressure water or 8% sodium tripolyphosphate (STPP). Impedance detection time (IDT) was recorded for rinsates of the products. Fish dipped in 2% lactic acid had higher initial IDT than those dipped in 1 % lactic acid. Regardless of lactic acid concentration, IDT were the same in products held more than one day at 4C. Similar results were achieved for products dipped in Pergenox®. Fillets spray‐washed in STPP had higher IDT than those dipped or spray‐washed with water; the difference being pronounced after six days at 4C. For whole fish, STPP had a very significant initial reduction in microbial counts (higher IDT). Exposing the product to high‐pressure spray wash for a short time did not have a significant effect on IDT, but the addition of STPP in the water did increase IDT, thus shelf‐life.