The inhibitory effect of commercial 'pure' oleuropein was tested against Salmonella enteritidis in a coliform broth and in reconstituted milk (model food system). It was found that the inhibition of this organism in the broth was influenced by the initial inoculum size, the pH of the medium and the concentration of additive. The inhibition was more pronounced in samples with low pH and low inoculum size. No such inhibition was evident in the model food system.