Simulation Modeling of a Multi Product Tomato Processing Plant S. A. Starbird, M. Ghiassi ABSTRACT T HE network based simulation language SLAM was used to model a proposed tomato processing operation. The model evaluates the feasibility of the proposed plant design in meeting pack plan (market share) requirements and the effect of various scheduling alternatives on the proposed plant's profitability. The results indicate that the proposed design will meet market share requirements and that scheduling based upon raw product quality will increase plant profit by $518,000 (12.8%) over net income earned from a traditional scheduling policy. INTRODUCTION Tomatoes are the second most important vegetable processed, in terms of raw product value, in the United States. California is the dominant producer with 84% of U.S. production valued at $421 million in 1982 (California, 1983). Other major producing regions are the Midwest (Illinois, Indiana, Ohio) with 7% of U.S. production valued at $85 million in 1982 and the East (New Jersey, Pennsylvania, New York, and the Delmarva Peninsula) with 1% of U.S. production valued at $26 million. California dominates the tomato processing market primarily because of the natural and technological advantages of the state. The natural advantages include favorable weather, adequate water, and available fertile land. The technological advantages of California include the development and early application of the mechanical harvester, higher yielding varieties of tomatoes, and the existence of an extensive transportation network (Brant, 1978). Processing tomatoes are harvested in California during an approximate 10-wk period beginning in mid- July and ending the first week of October. A tomato processing firm operating in the Santa Clara Valley of California recently completed a relocation study in response to a shift in the location of the principle growing regions of processing tomatoes, and the industrial expansion of Silicon Valley. The primary issue considered in the study was the location of its new processing facility. Plant design, pack plan (which refers to the quantity and allocation of end products), and raw product quality were secondary considerations of the study. This paper uses a simulation model to define the general structure of this multi-product tomato processing operation and to examine the affects of plant design and raw product quality on the profitability of the Article has been reviewed and approved for publication by the Food Engineering Div. of ASAE. The authors are: S. A. STARBIRD, Institute of Agribusiness, and M. GHIASSI, Assistant Professor, Decision and Information Sciences, University of Santa Clara, CA. proposed plant. The use of a model to examine these issues is essential since the crop's brief 10-wk season makes in-plant experimentation impractical and costly. The primary objectives in creating the model were: 1. To determine the technological feasibility (design vertification) of the proposed plant to meet production objectives. 2. To evaluate several production scheduling alternatives for feasibility and profitability, and 3. To investigate strategies for planting, harvesting and business planning. BACKGROUND AND SYSTEM DESCRIPTION Fig. 1 represents the entire tomato processing system from growing to distribution and Fig. 2 represents the major activities occurring within the processing subsystem. Activities that occur outside the processing subsystem are not considered in this paper. The modern tomato processing plant is a multi- product flow /job shop manufacturing facility through which tomatoes are routed to produce one of two broad product categories: paste products or peeled products. Paste products are created by disintegrating raw tomato solids and skins. The pulp is then concentrated by evaporating water from it. Ingredients such as spices, sugar, salt, soybean oil, and citric acid are added to the concentrated pulp to differentiate end products. End products are classified based upon percentage solids, particle size, and ingredients. Pado's Pizza Sauce (11% solids, 3.81 mm particle size) and 26% Tomato Catsup (26% solids, 0.838 mm particle size) are examples of paste products. Peeled products are created by peeling the whole tomato, chopping it into various sizes, adding ingredients, and canning the product. Peeled tomatoes are easily examined by the consumer, so high quality tomatoes are required. Mac's Salsa (25.4 x 25.4 x 0.635 GROWING \ f HARVESTING y 1 ASSEMBLY y ' PROCESSING y ' 1 DISTRIBUTION Fig. 1—Major functions of the tomato processing industry. 324 © 1986 American Society of Agricultural Engineers 0001-2351/86/2901-324$02.00 TRANSACTIONS of the ASAE