GRAM-NEGATIVE BACTERIA INHIBITION BY LACTIC-ACID CULTURE AND FOOD PRESERVATIVES ON CATFISH FILLETS DURING REFRIGERATED STORAGE

Treating catfish fillets with sodium acetate (SA) and/or potassium sorbate (PS), with or without lactic culture (Lactococcus lactis spp. cremoris ATCC 19257 grown in 20% milk solids) was studied at 4 degrees C. Gram negative bacterial (CVT) counts on crystal violet tetrazolium chloride agar, pH, and sensory evaluation of fillets were assessed over time. Treatment with the combination of 0.50% SA, 0.25% PS with 2.50% lactic acid culture (LC) and, also, 0.50 to 1.00% SA alone completely inhibited growth for greater than or equal to 6 days at 4 degrees C. After 12 days, counts with this treatment and the 1.00% SA increased approximate to 1.3 and 1.2 log cycles, respectively. The antimicrobial effects did not appear to be due to pH values. The combination of 0.50% SA and 0.25% PS with 2.50% LC, or 1.00% SA, alone, improved catfish odor and appearance during 13 days storage.