Survival of Vegetative Pathogens in Model Flavor Systems Containing Medium Chain Triglycerides

Introduction: The most commonly used carrier compounds in flavor-based systems in the food industry are ethyl alcohol, propylene glycol, medium chain triglycerides, or triacetin. Previously we have presented a study on the antimicrobial properties of ethyl alcohol, propylene glycol, and triacetin in food flavor systems.  The new study was undertaken to evaluate the bactericidal effect of medium chain triglycerides at different concentrations on the survival of various vegetative pathogens.

Purpose: The objectives of this study were: (1) to evaluate the antimicrobial properties of medium chain triglycerides on the survival of Salmonella spp., E. coli O157:H7, S. aureus, and L. monocytogenes, (2) to find the optimum concentration of this carrier compound that may be bactericidal (ex: 5-log reduction) for vegetative pathogens

Methods: Cultures (1 g) of S. Typhimurium, E. coli O157:H7, S. aureus, and L. monocytogenes were added to 9 ml of glycerol with the medium chain triglyceride concentrations of 50, 60, 70, 80, and 90% to achieve an initial inoculation of 6-7 log CFU/ml. All the sample concentrations were performed in duplicate. The samples were stored at ambient temperature. Microbiological analysis was performed following 0, 1, 3, 7, 14, 21, and 31 days of storage.

Results: Results indicated that the bactericidal effect was due to the combination of concentration and storage time. The optimum bactericidal concentrations that caused a 5-log reduction (P < 0.05) in vegetative pathogens were 90% for medium chain triglycerides.

Significance: The current study provides additional scientific basis for the antimicrobial effect of different chemical carrier compounds routinely used in food flavor systems.