Improving food safety in Vietnam’s traditional pork supply chain: evaluation of interventions in slaughterhouses and markets through a One Health approach

Foodborne diseases linked with pork consumption remain a major public health concern in low- and middle- income countries, where traditional supply chains dominate, food safety controls are limited, and interventions are under-explored. This thesis tested and evaluated food safety interventions in pig slaughterhouses and traditional markets, using a One Health approach that integrates microbiological, behavioural, economic, and socio-cultural perspectives. Two intervention studies were conducted across five provinces in the north, central, and south of Vietnam. At 16 slaughterhouses, a controlled trial evaluated a technique-based (low-cost equipment and hygiene training) and an incentive-based (performance-based inspection with financial rewards) intervention. At 68 traditional markets, a randomised controlled trial assessed interventions including vendor training, inspection and public disclosure, equipment provision, and a consumer awareness campaign. A total of 192 samples from slaughterhouses (pig carcasses and workers’ hand swabs) and 814 samples from markets (cut pork and cutting board swabs) were analysed for total bacterial count, Salmonella, coliforms, and Escherichia coli, alongside pre- and post- intervention observations and interviews (486 participants each round). Baseline findings demonstrated high microbiological contamination and poor hygiene practices at both slaughterhouses and markets. Interventions improved knowledge, hygiene practices, equipment availability, and additionally at the market level, increased vendor revenues. Microbiological reductions were observed for certain indicators at slaughterhouses but remained consistently high at markets, indicating the influence of interacting factors, including hygienic practice, infrastructure, environmental conditions, and socio-economic dynamics along the supply chain. Consumer awareness and risk perception exhibited a limited response to the consumer campaign, and purchasing behaviour remained unchanged. This thesis contributes to the evidence based on intervention effectiveness under real-world conditions, suggesting that future strategies should emphasise consumers as active drivers of demand for safe food, combined with coordinated structural and regulatory improvements across the supply chain.