The product’s freshness is essential in light of the current situation and the health-conscious consumer. As the product ages, its vitality diminishes, resulting in a decrease in demand at the same price. The selection of an appropriate credit strategy can generate a multitude of advantages for retailers by growing demand. Additionally, implementing a time-dependent reduction in selling price might enhance sales by serving as a type of price discount.Therefore, driven by this factor, the business provides a limited term of credit to the merchant. This study investigates the influence of customers’ credit amount, credit term, and item retail price on market demand. Given that the quality and freshness of a product have a direct influence on its attractiveness and appeal. The market demand is subject to temporal fluctuations. This study introduces a supply chain model for a perishable agricultural product that encompasses suppliers, retailers, and consumers. The model considers the fluctuating demand and suggests that the merchant should implement a partial credit policy to incentivize consumers to make larger purchases. The best option is selected by maximizing the average profit derived by the system. A search operation is executed using a Particle Swarm Optimization (PSO) method that has been devised, verified, and implemented. Speculative illustrations are employed to produce a model representation.