Antibacterial properties of lauric acid in combination with organic acids against major pathogens causing dairy mastitis

Abstract

The objective of this study was to determine the antibacterial properties of lauric acid in combination with acetic acid and lactic acid against major dairy mastitis pathogens including Staphylococcus aureus, Streptococcus agalactiae, Streptococcus uberis, Escherichia coli and Klebsiella spp. The antibacterial effect of each acid and the acid mixtures was evaluated by their minimum inhibitory concentration (MIC) and minimum bactericidal concentrations (MBC) using broth microdilution method. The differences in, MIC and MBC values of lauric acid and acid mixtures for each pathogen were calculated by applying the one-way analysis of variance (ANOVA) and Turkey’s multiple-range tests were used for pairwise comparison. Results demonstrated that acetic acid had the highest inhibitory and bactericidal effect against all tested pathogens with the lowest MIC and MBC values of 0.125% and 0.25-1 %w/v, respectively. The mixture of lauric acid with acetic and lactic acid exhibited significant higher inhibitory and bactericidal effects by having the lower MIC and MBC values against all tested pathogens when compared with lauric acid alone (P < 0.05). In conclusion, acetic and lactic acid can enhance antibacterial properties of lauric acid against major mastitis pathogens.