89D-19

The phenolic antioxidants BHA, BHT, TBHQ, and PG are some of the most widely used antioxidants in the food industry.  In addition to the antioxidant ability of these phenolics, many studies have provided information on the killing effects of phenolic antioxidants on pathogenic fungi and a large number of bacteria including foodborne pathogens.  One approach for the control and prevention of foodborne pathogens and spoilage organisms is using naturally occurring food ingredients.  Spice plants' secondary components have been found to be powerful antimicrobials.  Commercial dried plums (Prunus domestica cv. French) contain phenolics, such as hydroxycinnamates, neochlorogenic acid and chlorogenic acid.  Previous studies with dried plum mixtures have shown that dried plum mixtures are capable of reducing foodborne pathogens in brain heart infusion broth using mixed five organism cocktail of foodborne pathogens but single organism cocktails have not been studied.  The objective of this study was to determine the effect of fresh plum juice concentrate concentration on microbial growth of Escherichia coli O157:H7 and Salmonella Typhimurium in three different liquid media. 

Separate bottles of brain heart infusion broth, distilled water, or 0.1% peptone with 0, 4, 6, or 10% plum juice concentrate were inoculated with separate two strain cocktail solutions of E. coli O157:H7 and S. Typhimurium.  The plum/broth mixtures were stored at 35°C and microbial analysis was performed at 0, 12, and 72 hours using tryptic soy agar.  

The distilled water and peptone water samples had static growth to 12 hours and then decrease at 72 hours.  The BHI samples had increased growth to 12 hours and showed fairly static growth to 72 hours with the majority of the treatment samples having less than the controls. 

The addition of fresh plum juice concentrate is able to prevent and decrease E. coli O157:H7 and S. Typhimurium growth in liquid systems.