99D-34 |
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T. KIM, Food Science and Technology, Mississippi State University, Box 9805, Starkville, MS 39762 and J. L. Silva, Dept. of Food Science & Technology, Mississippi State Univ., 205 Herzer Bldg., Campus Mailstop 9805, Mississippi State, MS 39762-9805. Numerous studies have been performed concerning the antimicrobial properties of plant sources. However, no studies have reported antimicrobial activities of muscadine (Vitis rotundifolia) seed extract (MSE) on food-borne pathogens. The ethanol extract of muscadine seed was examined for its antimicrobial activity against Eschericia coli O157:H7, Salmonella Typhimurium, or Listeria monocytogenes in saline solution. The minimum inhibition concentration (MIC) of MSE was determined on Listeria monocytogenes by using broth dilution assays. A stock solution of 350 mg/mL of MSE was diluted to appropriate concentrations (25 to 200 mg/mL or 1 to 25 mg/mL) with 1 mL of sterile saline solution or tryptic soy broth (TSB). Then, about 5.5 ~ 6.5 log cfu/mL of each of the three pathogens were added and incubated at 37 °C. After incubation for 1, 2, and 3 h in saline solution or 4, 8, 12, 16 and 24 h in TSB, samples were serially 10-fold diluted. The proper dilution was spread-plated on tryptic soy agar (TSA) in duplicate. After incubation at 37 °C for 24 ~ 48 h, viable counts were obtained. Listeria monocytogenes and Salmonella Typhimurium were completely inactivated at 25 mg/mL MSE in saline solution after 1 and 2 h, compared to the control (~ 5.5 log). E.coli O157:H7 in saline solution was completely inactivated at 100 mg/mL after 3 h. The MSE at 25 mg in TSB showed the highest log reduction (~6.5) at 24 h, showing that MIC of MSE was less than 5 mg/mL on Listeria monocytogenes.
Session 99D, Food Microbiology: General
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