Antibacterial Efficacy of Essential Oils from Four Spices against Salmonella typhimurium: Mathematical Modelling and Application in Enhancing Salad Cream Safety

Phattaraporn Lertchirakarn¹ and Rattana Muangrat^2,3*

¹Division of Food Science and Technology, Faculty of Agro-Industry, Chiang Mai University, Mae-Here, Muang, Chiang Mai, Thailand.

²Division of Food Process Engineering, Faculty of Agro-Industry, Chiang Mai University, Mae-Here, Muang, Chiang Mai, Thailand.

³Bioactive Compound Extraction Research Unit, Faculty of Agro-Industry, Chiang Mai University, Chiang Mai, Thailand.

Corresponding Author E-mail: rattana.m@cmu.ac.th

The study was conducted to investigate the inhibitory effects of certain natural substances (finger root, clove, lemongrass, cardamom, and the combination of lemongrass with cardamom) against Salmonella typhimurium, a type of bacteria known to cause foodborne illnesses. The result showed that finger root, clove, lemongrass, cardamom, and the combination of lemongrass with cardamom exhibited strong inhibitory effects against S. typhimurium. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were evaluated. MIC values ranged from 0.049 to 0.781 µl/ml, and MBC values ranged from 0.049 to 6.250 µl/ml. Furthermore, the study aimed to develop mathematical models that accurately describe S. typhimurium survival in the presence of these essential oils. By understanding how the S. typhimurium respond to the oils over time, it was found that the mathematical models accurately described bacterial survival, with the modified Gompertz model fitting for finger root essential oil and the Weibull and modified Gompertz models suitable for the other oils. Additionally, the study sought to evaluate the practical viability of incorporating these essential oils into salad cream formulations, primarily aiming to assess their potential in reducing S. typhimurium counts and ensuring compliance with established quality standards. Specifically, the inclusion of finger root, clove, lemongrass, cardamom, and the combination of lemongrass with cardamom in salad cream formulations, maintained at a controlled temperature of 4 °C, yielded positive outcomes, meeting the required quality standards. Importantly, the presence of S. typhimurium was rendered undetectable, and an overall reduction in microbial count was observed when compared to cream formulations lacking these essential oils. This study effectively underscores the potential of the examined essential oils as natural antimicrobial agents suitable for incorporation in food products

Essential Oil; Kinetic Models; Minimum Inhibition Concentration; Minimum Bactericidal Concentration; Salmonella typhimurium

[ HTML Full Text]