INHIBITION OF LISTERIA-MONOCYTOGENES AND OTHER BACTERIA BY SODIUM DIACETATE

Growth and survival patterns of Listeria monocytogenes strain Scott A were studied in brain heart infusion broth containing sodium diacetate. Minimum inhibitory concentrations decreased with decrease in temperature, from 35 and 32 mM at 35C and 20C, respectively, to 28 mM at 5C. Broth pH containing 35, 32, and 28 mM sodium diacetate was 5.25, 5.40 and 5.60, respectively. Sodium diacetate was more effective than acetic acid alone in inhibiting the organism over the pH range of 5.0-6.0. Addition of 21 mM (0.3%) sodium diacetate to ground beef or beef slurry suppressed total aerobic counts during refrigerated storage. Although the meat pH decreased from 5.6 to 5.2 by the addition of the compound, a major part of the antimicrobial effect was attributed to the diacetate and not just pH. Sodium diacetate suppressed growth of three additional L. monocytogenes strains and strains of Escherichia coli, Pseudomonas fluorescens, Salmonella enteriditis and Shewanella putrefaciens. P. fragi, Yersinia enterocolitica, Enterococcus faecalis, Lactobacillus fermentis and Staphylococcus aureus were insensitive to the compound. Sodium diacetate has potential for use in controlling growth of listeriae in meat, poultry and fish products and suppressing growth of certain Gram-negative spoilage and pathogenic microorganisms.