Antimicrobial Activity of Cinnamaldehyde, Carvacrol, and Lauric Arginate against Salmonella Tennessee in a Glycerol-Sucrose Model and Peanut Paste at Different Fat Concentrations

Abstract

The objective of this study was to investigate the antimicrobial activities of carvacrol, cinnamaldehyde, and lauric arginate (LAE) against Salmonella in a low water activity (aw) glycerol-sucrose model and in peanut paste with different fat concentrations. Salmonella Tennessee was inoculated into the model and the low fat (<5%) and high fat (50%) peanut paste adjusted to aw 1.0, 0.7, 0.5, and 0.3 and with or without cinnamaldehyde, carvacrol, or LAE. The survival of the bacterium over 3 or 5 days at 25°C was evaluated. Reduced aw alone decreased the viable population over time, with the highest reduction at the lowest aw. In the glycerol-sucrose model, all antimicrobial agents significantly reduced the population over time (P < 0.05) compared with the controls. LAE was more lethal than the essential oil components, reducing the population to undetectable levels by day 2 for all aw. Cinnamaldehyde was more effective than carvacrol at aw 0.5 and 0.3 (2.7- to 2.9-log versus 0.39- to 1.97-log reductions on day 3). In low-fat peanut paste, none of the antimicrobial agents inhibited growth of the pathogen at aw 1.0. However, inactivation was enhanced at reduced aw. Cinnamaldehyde and LAE both reduced the pathogen population to undetectable levels on day 5 at the highest concentration tested (ca. 10 times higher than that in the glycerol-sucrose model). Inactivation efficacy of all antimicrobial agents was greatly decreased but not eliminated in 50% fat peanut paste. Results suggest that the test antimicrobial agents were effective under low aw conditions, but significantly higher concentrations are needed for potential food applications, and fat concentration can negatively impact the efficacy of these antimicrobial agents.