A preferred supplier has the benefits of economies of scale, high quality and freshness, low lead time, low out of stock and yield loss, low number of suppliers, low distribution cost, contractual arrangements, quality control systems, and low negotiation and risk factors; whereas the drawbacks include potential rejection of products, financial penalties, and high asset specificity. TOPS converted its regular suppliers into value-added suppliers by adding such activities as quality control, cutting, trimming and packing.
Furthermore, Rong et al. [25] analyzed the design and operation of a food distribution system to maintain optimal quality of fresh food throughout the supply chain, using a mixed-integer linear programming model.
Their model considered quality degradation, temperature control, shelf life, and transportation lead times.
Several recent research reports are directly applicable to mangosteen farmers. Jaritngam [26] investigated a method of checking for defects in mangosteens. Rattanatraipob [27] studied methods to extend mangosteen shelf life.
Other researchers who have studied the benefits of farmers groups and cooperatives are Kladpuang [9] and Bamrungcheep [8].
Focusing on the marketing and distribution of mangosteens, the Kenan Institute Asia [28] studied the potential for central market settlement in Chantaburi, and a distribution system for domestic and international markets. In addition, a survey of the mangosteen supply chain in Indonesia was carried out by Dimyati.