Efficacy assessment of various natural and organic antimicrobials against Escherichia coli O157:H7, Salmonella enteritidis and Listeria monocytogenes

Abstract

Abstract Background Foodborne illness is a public health alarm with a deleterious effect on human health and the economy all over the world. Searching for possible solutions to beat foodborne pathogens is still a demanding concern. The scope of this study is to evaluate the antimicrobial activity of some natural and organic compounds against important pathogens including Escherichia coli O157:H7 C9490, Listeria monocytogenes Lm2 Scott A 4b, and Salmonella enteritidis 8-9-99. Results The bactericidal effect of eight compounds and their concentrations were evaluated by the tube dilution assay against the tested bacterial strains. Thymol was found to be superior to all tested compounds. Antimicrobial activities found to be highly influenced by varying pH values. Low pH 4.5 found to report higher inhibition when compared with pH 7.1. For instance, minimum inhibitory concentration (MIC) occurred at pH 7.1 with 25 ppm of thymol against Escherichia coli O157:H7 and Salmonella enteritidis, while 200 ppm against Listeria monocytogenes. However, MIC occurred at pH 4.5 with 25 ppm of thymol against all tested bacterial strains. Conclusions Thymol is the most active antimicrobial recorded in our study at low concentrations. Our results indicated thymol, benzoic acid, sodium benzoate, salicylic acid, 3-t-butyl-4-Hydroxyanisole, and acetylsalicylic acid have promising potential applications in controlling tested foodborne pathogens.

Keywords

• E. coli O157:H7
• L. monocytogenes
• S. enteritidis
• Food preservation
• Antimicrobials