SURVIVAL OF AEROMONAS-HYDROPHILA IN FRESH TOMATOES (LYCOPERSICON-ESCULENTUM MILL) STORED AT DIFFERENT TEMPERATURES AND TREATED WITH CHLORINE

This study examines the survival of two Aeromonas hydrophila strains ( A, hydrophila ATCC 7965 [strain A] and A. hydrophila isolated from foo d [strain BI) on the surface and core tissue of fresh tomatoes stored at different temperatures and the efficacy of chlorine treatment on th eir survival. Counts of A. hydrophila on the surface of tomatoes store d at 25 and 35 degrees C were significantly higher between days 1 and 4 for both strains as compared to results obtained at 6 degrees C. Cor e tissue counts of A. hydrophila cells on tomatoes dipped in a cellula r suspension at 25 degrees C and stored at 25 degrees C were significa ntly higher (P < 0.05) than counts obtained with dip suspensions at 6 or 35 degrees C. In chopped tomatoes stored at 25 and 35 degrees C, po pulations of aerobic mesophiles showed significant increases after 96 and 70 h, respectively. The populations of both A. hydrophila strains in chopped tomatoes stored at 6 degrees C increased significantly afte r 96 h, while at 25 and 35 degrees C the counts increased in the first hours of incubation. Viable counts of A, hydrophila on the surface an d central tissue of tomatoes significantly decreased (P < 0.05) when t he samples were dipped for 2 min in chlorine at a concentration of 50 ppm (50 mu g/ml). The results suggest that tomatoes should be kept at low temperatures during storage, shipping, and retail stocking and tha t chlorine at a concentration of 50 ppm should be used to reduce the l evels of A. hydrophila.