89D-32 |
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S. A. IBRAHIM, S. R. K. Dharmavaram, and C. W. Seo. Food Science & Nutrition Program, North Carolina A&T State Univ., Dept. of Human Environment & Family Sciences, 171-B Carver Hall, Greensboro, NC 27411-1064 Escherichia coli O157:H7 and Salmonella are the major foodborne pathogens that are a great concern to consumers and cost annual significant losses to food industry. Origanox, a commercial spice, has been shown to have antimicrobial properties. The objective of this research was to determine the effectiveness of Origanox alone and in combination with sodium acetate and sodium lactate on inactivation of E. coli O157:H7 and Salmonella typhimurium in Brain Heart Infusion (BHI) broth. Batches of BHI broth containing several combinations of sodium lactate (0, 1, and 2 % w/v), sodium acetate (0, 0.05, and 1 % w/v), and Origanox (0, 0.075, and 0.15 % w/v) were prepared and sterilized at 121 C for 15 min. Overnight cultures of five E. coli O157:H7 strains (E1730, E 4546, E 0019, Cider and 944) and two strains of Salmonella typhimurium (O2 and O3)were then individually inoculated into BHI broth (2 log CFU/ml). The inoculated samples were then stored at 37o C for 12 hrs and changes in bacterial population were followed using optical density O.D. 610 nm) measurements. At the end of incubation period, samples were serially (1:10) diluted and 100ml of appropriate dilution was surface plated on Tryptic soy agar. The plates were then incubated at 37 C to determine the bacterial populations. Our results indicated that Origanox was effective in controlling the growth of both E. coli O157:H7 and salmonella at concentration of 0.15 % in BHI broth. Sodium lactate alone was found to be effective at 2% concentration. Sodium lactate or sodium acetate (1%) in combination with 0.075% Origanox was effective in controlling the growth of both E. coli O157:H7 and Salmonella > 3 log reduction. Treatments containing a combination of 1% sodium lactate, 1% sodium acetate and 0.075% Origanox showed significant reduction in bacterial population, > 5 log reductions. The use of Origanox as natural ingredient could reduce the usage of chemical preservatives such as sodium lactate and sodium acetate to inhibit the growth of E. coli O157:H7 and Salmonella typhimurium.
Session 89D, Food Microbiology: Antimicrobial effects on foodborne microorganisms
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |