Assessing sustainability of food supply chains by using a novel method integrating group multi-criteria decision-making and interval Type-2 fuzzy set

A framework is required to assess the current sustainability status of food supply chains (FSCs) and identify the weak aspects. This paper proposes a novel method integrating group multi-criteria decision-making and interval Type-2 trapezoidal fuzzy (IT2TrF) set to develop a sustainability index for FSCs. A food company and five industry experts are selected to participate in a case study to demonstrate the application of this method. Fifteen criteria and 33 sub-criteria related to the FSC are identified based on the available literature and the opinions of the participating experts. The company’s performance in terms of sub-criteria is obtained using the Bonferroni mean operator to aggregate the judgment of a group of experts. The best–worst decision-making method is applied to determine an expert’s weights of criteria and sub-criteria. Due to the existence of qualitative criteria, sub-criteria, and incomplete information in experts’ judgment, an IT2TrF set-based approach is utilized to obtain the overall sustainability index. The Euclidean distance measure is applied to determine the sustainability status through the entire FSC based on the IT2TrF calculations, and the FSC sustainability index is obtained. The case study results indicated a “very sustainable” sustainability status. Also, using the ranking score method and threshold analysis, nine weak points are identified, including efficiency, agility, professional development, modes of transportation, time utilization, equal opportunities, health and prosperity. In addition, improvement measures are suggested for each weak point. Finally, comparative analyses with other cases are carried out to validate the results. The results confirm the efficiency of the proposed model and its ability to include more levels of uncertainty than the conventional fuzzy approaches.