Hidden middle governance reduces antibiotic residue health risks and food loss in aquatic supply chains

The "hidden middle" of food supply chains, referring to the small- and medium-scale intermediaries linking producers to markets, often obscures food safety risks and exacerbates losses. Integrating aquatic product testing data from 247 Chinese prefectures (2015-2022), we assessed the cross-regional impact of antibiotic residues (ARs) through the hidden middle of China's aquatic supply chains. We found that AR above legal limits caused 44,200 tons of food loss and health risks exceeding safe thresholds in six provinces. We then developed an optimization model to allocate sampling resources, resulting in 14,702 tons of food loss reduction and 77% decrease in health risks. Relative to current monitoring schemes, the optimized strategy delivered an additional 6,951-ton reduction in food loss and a 17% larger risk reduction per province per year. Our results demonstrate that focusing governance on AR spread through the hidden middle can improve food safety and reduce risks to food security and public health.