Quantitative LAMP and PCR Detection of Salmonella in Chicken Samples Collected from Local Markets around Pathum Thani Province, Thailand

Abstract

Salmonella is a bacterium that infects people when they consume contaminated food or liquids. To prevent humans from becoming ill, it is useful to have an efficient method of detecting Salmonella before the disease is passed on through the food chain. In this research, the efficiency of Salmonella detection was compared using the following four methods: conventional loop-mediated isothermal amplification (LAMP), PCR, quantitative LAMP (qLAMP), and qPCR. The artificial infection of chicken samples started with incubating of 10 mL of 108 CFU of S. typhimurium for 6 hr. and enriching for 2 hr. to represent real contamination of the samples. The results show that the sensitivity of Salmonella DNA detection in PCR, qPCR, LAMP, and qLAMP were 50 ng, 5 ng, 50 pg, and and 500 fg, respectively. Thirty samples of 10 g chicken were collected from 10 markets in Pathum Thani, Thailand; then, the infection was detected. The conventional LAMP, qLAMP, and qPCR methods detected Salmonella in all the chicken samples. However, the conventional PCR method detected Salmonella infection in only eight of the samples. Overall, the qLAMP method had the highest sensitivity of Salmonella DNA detection.