OPTIMAL SCHEDULING FOR RETORTS OF DIFFERENT CAPACITIES IN FOOD CANNERIES

Our research objective was to develop a mathematical model for optimized scheduling at a food cannery that uses different capacity retorts to sterilize a given amount of different canned food products with specific quality requirements. The developed model was based on mixed-integer linear programming (MILP) and incorporated the possibility of simultaneous sterilization. Simultaneous sterilization could be characterized as a capability that allows for sterilization of different products in various container sizes in the same retort. The possibility of simultaneous sterilization became a cornerstone of the optimization approach proposed in this study. A polynomial time computer procedure for generating nondominated simultaneous sterilization vectors was proposed. Its utilization avoids the computation of all possible subsets of products and, therefore, significantly reduces the time needed for computation of nondominated simultaneous sterilization vectors. In order to demonstrate the feasibility of the MILP model, several examples involving the sterilization of different products were included in the present research. This study presents examples demonstrating that for randomly generated quantities of products a reduction in plant operation time between simultaneous and nonsimultaneous operations occurs within the range of 20–25%, which could, of course, be significant for achieving higher economic returns. The proposed methodology is of special relevance for small- and medium-sized food canneries that normally work with many different products simultaneously. PRACTICAL APPLICATIONS In the present research, a mathematical model was developed for optimized scheduling at a food cannery that uses different capacity retorts to sterilize a given amount of different canned food products with specific quality requirements. The examples presented in this study demonstrate that a reduction in plant operation time between simultaneous and nonsimultaneous operations was in the range of 20–25%, which could, of course, be significant for achieving higher economic returns. The proposed methodology is of special relevance for small- and medium-sized food canneries that normally work with many different products simultaneously.