Inactivation of Escherichia coli O157:H7 and Listeria monocytogenes in milk by caprylic acid and monocaprylin

• Published in: Food microbiology Vol. 21; no. 5; pp. 611 - 616
• Main Authors: Nair, Manoj Kumar Mohan, Vasudevan, Pradeep, Hoagland, Thomas, Venkitanarayanan, Kumar
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01.10.2004; Elsevier
• Subjects: antibacterial properties; bacterial contamination; Biological and medical sciences; Caprylic acid; E. coli O157:H7; Escherichia coli; Escherichia coli O157:H7; food contamination; Food industries; Food microbiology; food pathogens; food storage; free fatty acids; Fundamental and applied biological sciences. Psychology; inactivation; L. monocytogenes; Listeria monocytogenes; Milk; Milk and cheese industries. Ice creams; monoacylglycerols; Monocaprylin; pathogen survival; refrigeration; retail storage temperature; storage temperature; E. coli O157:H7; L. monocytogenes; Caprylic acid; Monocaprylin; Milk; Escherichia coli; Dairy product; Listeria monocytogenes; Bacteria; Inactivation; Enterobacteriaceae
• ISSN: 0740-0020; 1095-9998
• DOI: 10.1016/j.fm.2004.01.003

Listeria monocytogenes and Escherichia coli O157:H7 are major foodborne pathogens implicated in various outbreaks involving pasteurized or unpasteurized milk, and various dairy products. The objective of this study was to determine the antibacterial effect of caprylic acid (CA, C8:0) and its monoglyceride, monocaprylin (MC) on L. monocytogenes and E. coli O157:H7 in whole milk. A five-strain mixture of E. coli O157:H7 or L. monocytogenes was inoculated in autoclaved milk (106CFU/ml) containing 0, 25, or 50mM of CA or MC. At 37°C, all the treatments, excepting 25mm CA, reduced the population of both pathogens by approximately 5.0logCFU/ml in 6h. At 24h of storage at 8°C, MC at both levels and CA at 50mM decreased L. monocytogenes and E. coli O157:H7, respectively by >5.0log CFU/ml. At 48h of 4°C storage, populations of L. monocytogenes and E. coli O157:H7 were decreased to below detection level (enrichment negative) by 50mm of MC and CA, respectively. Results indicate that MC could potentially be used to inhibit L. monocytogenes and E. coli O157:H7 in milk and dairy products, but sensory studies need to be conducted before recommending their use.