Effect of a lactic starter culture on the growth and protease activity of Aeromonas hydrophila

Lactococcus lactis subsp. lactis strain Lac 388 (isolated from goats' cheese made without starter) had inhibitory activity against three strains of Aeromonas hydrophila either by the plating method or by the associative culture approach (broth, skim milk and ewes' milk). Low pH was only partially responsible for the antagonism. Inhibition due to hydrogen peroxide and nutrient depletion was excluded. This inhibitory compound(s) was not destroyed by proteolytic enzymes. In mixed cultures the strains of Aer, hydrophila did not produce detectable amounts of protease.