**3. Circular and lean food supply chain**

Today's business environment is a very dynamic one with the rapidly changing consumer preferences, which pressures the business to respond to customers' needs and wants, become more sustainable, and cost efficient. In recent years, sustainability has become an emerging goal of food supply chain due to the sustained attention of various aspects to environmental issues. According to Consumers are increasingly interested in the sustainability behind products (raw materials, procurement, packaging and transportation). In addition, due to the pressure of government regulation and consumers' increasing awareness of environmental issues in consumption, many enterprises are forced to turn their supply chain model into a circular supply chain. However, the circular food supply chain can also bring many other benefits to the company. For instance, Beske et al. [64] pointed out that circular supply chain can help companies provide consumers with higher quality and safer food [64]. Geissdoerfer et al. [65] also mentioned that the circular supply chain can reduce food waste, improve brand benefit and increase long-term profits [65–67]. As a result, food companies need to use a circular supply chain to improve their customer loyalty and competitive advantage.

At the same time, some scholars also discussed challenges faced by the circular food supply chain. Carbon emissions and other environmental pollution of the food supply chain (waste cooking oil supply chain) after the implementation of the circular supply chain and concluded that the impact of the supply chain on the environment has been significantly reduced, but the short-term economic benefit is still a challenge. Food waste is caused by food packaging, so food packaging is a challenge for the circular supply chain. In addition, many farmers in developing countries generally lack sustainable knowledge, which may affect the implementation of the circular supply chain Finally, weak regulation of laws and regulations, lack of pressure from the market and lack of support from other stakeholders in the supply chain are all challenges faced by the circular food supply chain. Circular economy brings the advantages renewability, reusage and recycling that the food sector needs.

On the other hand, lean supply chain provides food companies with a series of practices that optimize supply chains through more efficient routes and usage of materials, cost efficiency and better management of customer demand. Due to the simplicity of lean principles, high productivity, short lead-time, and improved overall efficiency were able to replace the decline of Computer Integrated Manufacturing (CIM) and became the standard of today's manufacturing practice.

Many research studies carried out in manufacturing industries showed that the owners are likely to adopt lean principles to the production due to the advantages that they acquire regardless of its scale. This is because either small or large business has its advantages of lean principles. The biggest size of SMEs is taken place in China with less than 999 employees, where in EU & UK estimated should be less than 250 employees. SMEs aim to have a better relationship with higher flexibility and strong work communication internally to have a simple and clear infrastructure for everyone to follow. On the contrary, large businesses aim to find access to resources and exploit them which will allow them to capitalize a market with a better lean supply chain than SMEs.

Lean production can help to reduce inventories for manufacturers since high inventories can result in inventory costs and available workplaces are minimized. Also, it can decrease any unnecessary times in supply chains such as lead times for customers, changeover time in using machineries and idle time of workers and educate managerial skills to upper managers and improved unskilled workers in the production. Applying lean principles, company will gain advantages in terms of increasing availability of machines and reducing manpower, bettering work environment in terms of higher safety and more organized workplace and also, more cost saving and higher profits as all potential wastes are eliminated, all hidden will also be eliminated.

Nevertheless, even though there are many advantages from applying lean principles, there are barriers obstructing lean productions to be implemented, which taken in accounts every organizations. Lean production is not suitable for applications that have high variations of customer demands and highly customized product. This is because lean principle aims to balance the flow production, which cannot respond to the rapid change in demand fluctuation. Thus, the lean idea such as Just-In-Time (JIT) can be ambiguous to be implemented in the production. Availability of supplies can also cause trouble since lean aims to keep only a small amount of inventory in the production in order to minimize unnecessary cost. This will trouble companies if unexpected circumstances occur such as employee strikes, error on products and transportation delays which can damage customer relationships and whole supply chains. Another factor is financial plan since it needs huge investment to develop regard to training cost, purchasing cost and takes huge amount of time to revolutionize entire organizations to have strong mindset; some employees are not willing to change their traditional way of working and afraid to make any mistakes regard to the new system.
