Survey of Listeria spp. and Salmonella spp. in Food, 2024

DOI: 10.6524/EB.202608_42(17).0001

Hsiao-Lun Wei^*, Jui-Hsien Chang, Ying-Shu Liao, Shiu-Yun Liang, Ru-Hsiou Teng, Chien-Shun Chiou

2026 Vol.42 NO.17

Correspondence Author： Hsiao-Lun Wei^*

Abstract：

Listeria monocytogenes and Salmonella spp. are important foodborne pathogens. This study, conducted in 2024, investigated Listeria spp. contamination in 100 dairy products, and both Listeria spp. and Salmonella spp. contamination in 57 shellfish samples, to assess potential sources of human infection. Results showed that Listeria spp. was not detected in any of the dairy products tested; however, some opportunistic pathogens with infection potential were found. In bivalve shellfish (29 oysters and 28 clams), Listeria spp. was not detected, but Salmonella spp. was found in 22.8% of the samples. The detection rates of Salmonella spp. in oysters and clams were 13.8% (4/29) and 32.1% (9/28), respectively. The Salmonella spp. isolates included 9 serotypes and 15 pulsed-field gel electrophoresis (PFGE) patterns. Among these, 5 PFGE patterns were identical to common human clinical serotypes. Some PFGE patterns matched strains of animal origin, indicating a possible epidemiological link between Salmonella in humans, animals, and food (environmental sources). This study revealed oysters and clams as high-risk foods for Salmonella contamination in the country. Strengthening public health education and emphasizing proper cooking methods are recommended to reduce infection risks. In addition, to mitigate Salmonella contamination in oysters and clams, the principles of the One Health should be implemented to improve water quality and waste management around livestock and aquaculture areas, blocking the transmission of zoonotic pathogens into the farming environment.