The paper seeks to address the inventory management problems of perishable food items being faced in a firm. We have provided a solution approach to the managers to help them in planning based on customer behavior and demand. The inventory management of perishable or Non- Instantaneous deteriorating items is the biggest issue in the present global market conditions. Due to the organoleptic properties of perishable inventory, it is difficult to maintain the standard. Variation in demand patterns is an important parameter to be considered from the management perspective. In this study, we used a Particle Swarm Optimization technique to optimize the inventory problem. The proposed method predicts the probability of demand and demand pattern at a particular period through particle swarm optimization and analyzed understock and overstock strategy of the fast food delivery firms.