Occurrence of Listeria monocytogenes and Salmonella Typhimurium in Fruit Juices from Local Stalls and Restaurant in Kuching, Sarawak

Abstract

Listeria spp. and Salmonella spp. are capable of causing food-borne outbreaks and diseases in humans. This study aimed to quantify and detect the occurrence of Listeria monocytogenes and Salmonella Typhimurium in fruit juices by utilizing Most Probable Number (MPN) in combination with Polymerase Chain Reaction (PCR). In this study, a total of 50 fruit juice samples, consisting of orange, papaya, watermelon, honeydew and apple were collected from Kota Samarahan and Kuching. Specific Polymerase Chain Reaction (PCR) assay targeting the virulence gene, hlyA gene in L. monocytogenes and fliC gene in S. Typhimurium was performed, with the expected size of 730 bp and 559 bp, respectively. MPN analysis showed that the estimated microbial loads of Listeria spp. and Salmonella spp. in all samples were more than 1100 MPN/g. However, based on the PCR analysis, none of the samples (0%) were positive for L. monocytogenes or S. Typhimurium. This study presented as a preliminary food safety screening for the occurrence of Listeria spp. and Salmonella spp. from retailed fruit juices. Hygienic practices and food safety measures should be adhered by all food vendors and restaurants in order to avoid foodborne disease outbreaks in the future. Keywords: fliC, hlyA, Listeria, PCR, Salmonella