Evaluation of Inhibitors for Rapid Enumeration of Psychrotrophic Bacteria

Abstract

Two inhibitors of the 17 tested inhibited growth of gram positive bacteria without causing inhibition of gram negative bacteria. These were crystal violet at 2 mg/1 and neotetrazolium chloride at 2 mg/1. In addition, basic fuchsin at 6 mg/1 produced only marginal reduction in counts of gram negative bacteria. These inhibitors might find further use in developing a test for psychrotrophic bacteria in the presence of non-psychrotrophic bacteria.