A survey of foodborne bacterial contamination in Chiang Mai Province, Thailand: A pilot study focused on Aeromonas and Vibrio

Background: The consumption of raw or undercooked food contaminated with microbial pathogens is a major cause of foodborne illness. Vibrio and Aeromonas are significant pathogenic bacteria found in raw seafood. Currently, the consumption of raw and undercooked seafood, including salmon, is becoming popular in Thailand. Nevertheless, studies focusing on the prevalence of human pathogenic Vibrio and Aeromonas in seafood and salmon in Thailand are scarce. Objective: This study aimed to detect Vibrio and Aeromonas in undercooked foods from Chiang Mai Province, Thailand. Materials and methods: Ten food samples (five spicy mixed seafood salads and five salmon sushi) individually collected in Chiang Mai, Thailand, from August to October 2024. Samples were processed as previously described and bacteria were identified by 16S rRNA gene amplification by PCR and Sanger sequencing. Results: The results indicated that three of ten (30%) were contaminated with human pathogenic Vibrio, V. parahaemolyticus, V. cholerae, and V. vulnificus. Moreover, Aeromonas species regarded as potential human pathogens, A. caviae, A. dhakensis, A. veronii, and A. hydrophila, were isolated from eight food samples (80%). Conclusion: Our findings suggest that undercooked seafood in Chiang Mai, Northern Thailand, frequently contains pathogenic bacteria, posing significant food safety risks.