Antimicrobial effects of mustard flour and acetic acid against Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica serovar Typhimurium

• Published in: Applied and Environmental Microbiology 2003-05, Vol.69 (5), p.2959-2963
• Main Authors: Rhee, M.S, Lee, S.Y, Dougherty, R.H, Kang, D.H
• Format: Article
• Language: English
• Subjects: acetic acid; Acetic Acid - pharmacology; Acids; Anti-Bacterial Agents - pharmacology; antibacterial properties; Bacteria; Biological and medical sciences; Escherichia coli O157 - drug effects; Escherichia coli O157 - growth & development; Escherichia coli O157 - pathogenicity; Escherichia coli O157:H7; flour; Food; Food Microbiology; food pathogens; food preservation; Food Preservation - methods; food preservatives; Food Preservatives - pharmacology; Foodborne Diseases - prevention & control; Fundamental and applied biological sciences. Psychology; Humans; Hydrogen-Ion Concentration; inactivation; Listeria monocytogenes; Listeria monocytogenes - drug effects; Listeria monocytogenes - growth & development; Listeria monocytogenes - pathogenicity; Microbiology; mustard; Mustard Plant - microbiology; pathogen survival; Public Health Microbiology; Safety; Salmonella; Salmonella enterica subsp. enterica serovar Typhimurium; Salmonella typhimurium - drug effects; Salmonella typhimurium - growth & development; Salmonella typhimurium - pathogenicity; storage temperature
• ISSN: 0099-2240; 1098-5336
• DOI: 10.1128/AEM.69.5.2959-2963.2003

This study was designed to investigate the individual and combined effects of mustard flour and acetic acid in the inactivation of food-borne pathogenic bacteria stored at 5 and 22°C. Samples were prepared to achieve various concentrations by the addition of acetic acid (0, 0.5, or 1%) along with mustard flour (0, 10, or 20%) and 2% sodium chloride (fixed amount). Acid-adapted three-strain mixtures of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica serovar Typhimurium strains (10(6) to 10(7) CFU/ml) were inoculated separately into prepared mustard samples stored at 5 and 22°C, and samples were assayed periodically. The order of bacterial resistance, assessed by the time required for the nominated populations to be reduced to undetectable levels against prepared mustards at 5°C, was S. enterica serovar Typhimurium (1 day) < E. coli O157:H7 (3 days) < L. monocytogenes (9 days). The food-borne pathogens tested were reduced much more rapidly at 22°C than at 5°C. There was no synergistic effect with regard to the killing of the pathogens tested with the addition of 0.5% acetic acid to the mustard flour (10 or 20%). Mustard in combination with 0.5% acetic acid had less bactericidal activity against the pathogens tested than did mustard alone. The reduction of E. coli O157:H7 and L. monocytogenes among the combined treatments on the same storage day was generally differentiated as follows: control < mustard in combination with 0.5% acetic acid < mustard alone < mustard in combination with 1% acetic acid < acetic acid alone. Our study indicates that acidic products may limit microbial growth or survival and that the addition of small amounts of acetic acid (0.5%) to mustard can retard the reduction of E. coli O157:H7 and L. monocytogenes. These antagonistic effects may be changed if mustard is used alone or in combination with >1% acetic acid.