Characteristics and antagonistic activity of lactic acid bacteria isolated from chilled fish products

In fish products, contrary to other foods, the commercial use of starter cultures is relatively unexploited. In this study, 61 isolates of lactic acid bacteria from lightly preserved, chilled fish products were characterized with special emphasis on their antagonistic activity and their possible use as starter cultures. The strains were phenotypically identified and characterized with regard to gas production, carbohydrate fermentations, production of off odours, H2O2-production, antagonistic activity and growth at 2, 5 and 10 degrees C. Growth at 10 degrees C was detected for all strains within 4 days. At 5 degrees C, 90% of the isolates were growing within 3-9 days. At 2 degrees C only 33% of the strains were growing within 9 days. Fourteen strains were selected for further testing of antagonistic activity against spoilage- and pathogenic bacteria at different pH in a disc assay. Two strains, a Leuconostoc spp. (V 6) and a Lactobacillus plantarum (LKE 5), differed from the other lactic acid bacteria by a very wide inhibitory spectrum for V 6 and by very distinct inhibition zones for LKE 5. The mechanisms of their inhibitory effects are discussed.