COMPARISON OF EDTA AND APO-LACTOFERRIN WITH LYSOZYME ON THE GROWTH OF FOODBORNE PATHOGENIC AND SPOILAGE BACTERIA

Combinations of ethylenediamifietetraacetic acid (EDTA) or apo-lactoferrin (Apo-Lf) and lysozyme were evaluated for their antimicrobial effectiveness in ultra-high temperature pasteurized milk against Pseudomonas fluorescens, Salmonella typhimurium, Escherichia coli O157:117, and Listeria monocytogenes. Neither P. fluorescens nor S. typhimurium growth was influenced by EDTA, Apo-Lf or lysozyme alone or in combinations. Escherichia coli O157:H7 was inhibited by EDTA alone, but no increase in antimicrobial effectiveness was noted in the presence of lysozyme. In contrast, EDTA and lysozyme had a significant interactive antimicrobial effect against L. monocytogenes. Apo-Lf, at concentrations up to 2.5 mg/ml, displayed similar inhibition patterns with lysozyme against the E. coli O157:H7 and L. monocytogenes; however, the magnitude of inhibition was much less and of little practical significance. When evaluated over time, EDTA (1.5-2.5 mg/ml)-lysozyme (150 mu g/ml) slowed growth of E. coli and was bactericidal to L. monocytogenes. Apo-lactoferrin (15 mg/ml)-lysozyme (150 mu g/ml) had little practical effect on E. coli growth but did slow growth of L. monocytogenes.