<p>Food loss in perishable agri-food systems undermines farmer livelihoods and global sustainability by wasting scarce natural resources and generating avoidable greenhouse gas emissions. Addressing this challenge requires integrated approaches that link financial, technological, and operational levers to strengthen resilience and reduce environmental burdens. This study develops a quantitative modelling framework that integrates advance payments from buyers with permissible trade credit from suppliers, channelling these financial flows toward preservation technologies that slow deterioration and toward innovation that stimulates demand and lowers processing costs. The model incorporates price- and innovation-sensitive demand, exponential preservation effects, and dynamic inventory equations across production and depletion phases. Analytical expressions for inventory trajectory, cycle length, and profit are derived, and the nonlinear optimization problem is solved using two swarm intelligence algorithms: weighted and constriction Particle Swarm Optimization. Numerical results show that near-complete advance payments combined with modest preservation investment can cut spoilage to roughly one-quarter of production while maintaining high profitability. Relative to a baseline without financing, the integrated strategy reduces food loss by nearly six per cent and increases profit by over eight per cent. Sensitivity analysis reveals that demand scale and processing cost are the dominant drivers of performance. Overall, the framework provides a decision-support tool that connects supply chain finance with preservation and innovation, offering a sustainable pathway for reducing food loss and improving environmental sustainability in perishable agri-food systems.</p>