This research focuses on a proposal to improve the purchase and supply processes for the food sector. An appropriate model for procurement management and monitoring is established. It is then validated that an adequate input purchase process reduces costs and improves the service quality of companies, which reduces delivery times to provide satisfactory service. Lean manufacturing tools, such as Value Stream Mapping (VSM), were applied to carry out the initial diagnosis of the process, activity analysis, and time measurements. Finally, the new process was standardized, and continuous improvement was achieved by applying purchasing management techniques. The research was experimental, and a pilot test was carried out in a company in the food sector. The results show that with the implementation of the new procedures, this company reduced the percentage of late deliveries, improved its service level and therefore its position in the industry.