sustainability Review Analyzing Barriers of Circular Food Supply Chains and Proposing Industry 4.0 Solutions Nesrin Ada 1 , Yigit Kazancoglu 2 , Muruvvet Deniz Sezer 3, * , Cigdem Ede-Senturk 3 , Idil Ozer 3 and Mangey Ram 4,5   Citation: Ada, N.; Kazancoglu, Y.; Sezer, M.D.; Ede-Senturk, C.; Ozer, I.; Ram, M. Analyzing Barriers of Circular Food Supply Chains and Proposing Industry 4.0 Solutions. Sustainability 2021, 13, 6812. https://doi.org/10.3390/su13126812 Academic Editors: Guo Li, Sachin Mangla, Jiasen Sun, Huamin Wu, Xiaohang Yue and Riccardo Testa Received: 19 February 2021 Accepted: 12 June 2021 Published: 16 June 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Department of Business Administration, Ege University, Izmir 35100, Turkey; nesrin.ada@ege.edu.tr 2 Department of Logistics Management, Yasar University, Izmir 35100, Turkey; yigit.kazancoglu@yasar.edu.tr 3 Department of Business Administration, Yasar University, Izmir 35100, Turkey; edecigdem@gmail.com (C.E.-S.); idilozer83@gmail.com (I.O.) 4 Department of Mathematics, Computer Science and Engineering, Graphic Era Deemed to be University, Dehradun 248002, India; mangeyram@geu.ac.in 5 Institute of Advanced Manufacturing Technologies, Peter the Great St. Petersburg Polytechnic University, 195251 Saint Petersburg, Russia * Correspondence: deniz.sezer@yasar.edu.tr; Tel.: +90-(232)-570-8978 Abstract: The concept of the circular economy (CE) has gained importance worldwide recently since it offers a wider perspective in terms of promoting sustainable production and consumption with limited resources. However, few studies have investigated the barriers to CE in circular food supply chains. Accordingly, this paper presents a systematic literature review of 136 papers from 2010 to 2020 from WOS and Scopus databases regarding these barriers to understand CE implementation in food supply chains. The barriers are classified under seven categories: “cultural”, “business and business finance”, “regulatory and governmental”, “technological”, “managerial”, “supply-chain management”, “knowledge and skills”. The findings show the need to identify barriers preventing the transition to CE. The findings also indicate that these challenges to CE can be overcome through Industry 4.0, which includes a variety of technologies, such as the Internet of Things (IoT), cloud technologies, machine learning, and blockchain. Specifically, machine learning can offer support by making workflows more efficient through the forecasting and analytical capabilities of food supply chains. Blockchain and big data analytics can provide the necessary support to establish legal systems and improve environmental regulations since transparency is a crucial issue for taxation and incentives systems. Thus, CE can be promoted via adequate laws, policies, and innovative technologies. Keywords: circular economy; food supply chain; industry 4.0; sustainability 1. Introduction According to the UN’s Food and Agriculture Organization, one third of food produced is lost or wasted every year [1]. The report also notes differences between low- and medium-, and high-income countries in terms of the losses at various stages of supply chains. In low- and medium-income countries, food loss mostly occurs at the beginning of the production and supply chains whereas food in high-income countries is thrown away by retailers or consumers to become food waste at the consumption stage [1]. Additionally, the reasons for food losses and waste vary by countries’ income level. In low-income countries, the causes are mostly related to financial restrictions and lack of technical knowledge in harvesting techniques and infrastructure whereas in medium or high-income countries the causes are connected to consumer behaviors and lack of coordination among stakeholders in the food supply chain. Overall, increasing food waste is becoming a global issue regarding food security, which requires simultaneous management of environmental, economic, and social impacts. Sustainability 2021, 13, 6812. https://doi.org/10.3390/su13126812 https://www.mdpi.com/journal/sustainability