Biofilms and antimicrobial-resistant food borne bacteria in informal markets and street-vended ready to eat foods: Lessons and priorities for Cambodia

Abstract

Foodborne infections remain a persistent public health challenge in low- and middle-income settings where informal markets and street-vended ready-to-eat foods play a major role in daily diets. In Cambodia, recent evidence from Phnom Penh city indicates substantial contamination of market foods and street-vended products with Escherichia coli (88% prevalence in ready-to-eat foods) and Salmonella (60% in street foods, 48.4% overall in market foods), suggesting significant exposure risks and gaps in food safety control. This narrative review synthesizes available evidence on microbial contamination in Cambodia's informal food sector, examines the role of biofilms in sustaining contamination on food-contact surfaces, explores the linkages between biofilms and antimicrobial resistance from a One Health perspective, and proposes practical, scalable surveillance and control options suitable for informal market settings. We conducted literature searches using PubMed, Web of Science, and Google Scholar for Cambodia-specific food safety studies and global literature on biofilm formation, persistence, and control in food environments. We included peer-reviewed publications, technical reports, and international guidance documents published between 2015 and 2025, with foundational earlier works. Available evidence from Phnom Penh (Cambodia) reveals high contamination prevalence in traditional markets and street-vended foods. The biofilm phenotype can enhance antimicrobial resistance through multiple mechanisms, including facilitation of horizontal gene transfer, sub-lethal antimicrobial exposure creating selection pressure, and harboring stress-tolerant cells. However, direct investigation of biofilm presence on food-contact surfaces in Cambodian markets has not been conducted, representing a critical research gap. Reducing foodborne disease risk and antimicrobial resistance transmission in Cambodia's informal food sector requires integrated actions addressing infrastructure, surveillance, and behavior change. Priority actions include expanding monitoring to include food-contact surface sampling; investing in water access and handwashing infrastructure; implementing vendor-focused training on proper cleaning sequences and equipment separation; piloting subsidized equipment upgrade programs; aligning with Codex Alimentarius frameworks for antimicrobial resistance surveillance; and conducting implementation research to identify feasible, effective interventions. Evidence is currently limited to Phnom Penh; geographic expansion and direct biofilm investigation represent important research priorities.