Natural antimicrobial activity of Thai red curry’s herbs on Salmonella Typhimurium DT104b

Abstract

The outbreaks of Salmonella spp. have been reported as the major cause of food- borne illnesses worldwide. Thai red curry paste is an important ingredient of cultural foods and consists of herbs that have potential natural antibacterial activity. The objective of this experimental study was to measure the individual antibacterial activity of Thai red curry herbs on Salmonella under three different extraction methods (Kaeng Kathi - oil using fresh coconut milk, Kaeng Kathi - oil using UHT coconut milk, and Kaeng Pa - water). During the conducted experiments, the individual activities of the extracted herbs on Salmonella enterica serovar Typhimurium U302 (DT104b) were investigated by agar diffusion method using SS agar followed by MIC and MBC assay using broth dilution method. Among the three extraction methods, the extraction using fresh coconut milk gave the highest antibacterial activity in all herbs, followed by UHT coconut milk and water. Fresh coconut milk extracted cumin (Cuminum cyminum) and lemongrass (Citronella citrate) gave the highest antibacterial activity, 1.6 ± 0.22 cm and 1.4 ± 0.24 cm, respectively. The MIC assay showed 125 μl/ml and 100 µl/ml, while the MBC showed 125 μl/ml and 150 μl/ml, respectively. Thai red curry paste ingredients possess a significantly promising antibacterial activity against the food-borne pathogen S. enterica Typhimurium U302 (DT104b).