1 Introduction

In recent years, extreme climate change and the COVID-19 pandemic have severely affected world food production (Cheng et al., 2020; Si et al., 2020; Zhong et al., 2020). Furthermore, the Russian-Ukrainian war has also affected the world food supply (Ben Hassen & El Bilali, 2022). A series of events has also further highlighted the vulnerability of agricultural food systemsFootnote 1 (Fan et al., 2022). Food waste mitigation is an essential factor and a global problem (Alamar et al., 2018; Avagyan, 2017, 2020; Morone et al., 2019b). Statistics show that the world food waste reached 931 million tons in 2019, and 17% of the world's total food production may end up wasted. In addition, compared to previous studies, food waste was high in all countries, regardless of income level. The State of Food Security and Nutrition in the World 2022 shows that the number of people affected by hunger in the world in 2021 reached 828 million, and approximately 29.3% of the world's population face moderate or even severe food insecurity (FAO et al., 2022).

Food waste significantly impacts the economy, society, and the environment (Avagyan, 2020; Garnett, 2011; Kibler et al., 2018; Liu et al., 2013). Relevant data show that the total cost of food waste is US $2.5 trillion per year worldwideFootnote 2. Among the impacts of food waste are the inefficient use of water and land and unnecessary greenhouse gas emissions, leading to diminished natural ecosystems and the services they provide (Alvarado et al., 2021; Cattaneo et al., 2021; Jafari et al., 2020; Otles & Kartal, 2018). If global food waste were considered a country, it would be the world's third-largest emitter of greenhouse gases. Additionally, food waste will lead to the decline of biodiversity,Footnote 3 affect farmers' income, increase the burden on low-income people, and hinder the realization of the world's poverty reduction goals. A rise in carbon emissions has a significant effect on infant mortality (Shobande, 2020). If this trend continues, SDG 12.3Footnote 4 will be difficult to achieve. Environmental sustainability will not be achieved and hunger will persist (Shobande, 2023; Shobande & Asongu, 2022).

Currently, the academic research on food waste primarily focuses on the definition of related concepts, the measurement methods, and the data collection of food waste. A small number of scholars have conducted empirical studies related to food waste. Fewer studies have collated and compared food waste policies.

Many studies have been conducted on the concepts related to food loss and food waste. However, there is no uniform definition of food waste. In addition, the different methodological approaches adopted address different types of “loss” or “waste”, leading to results which are not comparable (Corrado & Sala, 2018; Xue et al., 2017). Table S1 summarizes the major international organizations and scholars' current definitions of food waste. It can be seen that the definition of food waste is defined by many scholars and institutions as the end of the supply chain and has a strong relationship with human behavior (Chaboud & Daviron, 2017; Parfitt et al., 2010; Zhang et al., 2019). Some scholars also believe that food waste should include the gap between the energy value of food consumed per capita and the energy value of food required per capita (Smil, 2004). Indeed, the absence of a consolidated methodological approach could undermine a deep understanding of the results from the recipient of the information (Corrado et al., 2019).

The measurement of food waste varies by stage. FAO's material flow model, research methods, and literature review methods are the more common measurements. The FAO material flow model divides the food supply chain into five segments. The five segments include production, post-harvest handling and storage, processing, distribution, and consumption. Calculation of food waste by stage using data from FAO food balance sheets (Huang & Nie, 2016; Kummu et al., 2012). The research method investigates food waste in one or more areas and at one or more points in the food supply chain and includes a variety of methods such as bookkeeping, archeological methods, weighing, and dietary review (Lu et al., 2022b). The literature review method makes judgments about the status of the food waste in response to the consolidation of the relevant research literature. The advantages and disadvantages of the various methods are compared in Table S2.

Food waste mitigation is a global problem, and many countries in the world have taken certain measures for food waste in terms of laws, systems, and policies. Policies play an important role in reducing food waste (Fesenfeld et al., 2022). Reducing food waste would contribute to addressing interconnected sustainability challenges, such as climate change, food security, and natural resource shortages. Therefore, developing an appropriate strategy for reducing FLW is one of the important issues related to sustainable development (Ishangulyyev et al., 2019). China has a tradition of food conservation since ancient times, but mostly restrains human behavior in terms of morality and habits. With modern management, including national policies, legislative system, action guidelines, and international cooperation, it still lags behind the international community, especially developed countries. Some scholars in China have reviewed the anti-food waste policies of the EU, the USA and some Asian countries (Shen, 2020; Shen et al., 2022; Yang et al., 2021; Zong, 2015). Huang Xisheng conducted a review and comparative study of overseas food conservation legislation, which provided a useful reference for China's Anti-Food Waste Law (Huang & Rao, 2021). Rosalinda Nicastro provides an overview of case studies and examples of legislation in different countries and actions taken by various players in the food chain and non-profit organizations in order to effectively prevent or reduce food loss and waste (Nicastro & Carillo, 2021a,b). The current academic review of food waste policies is primarily focused on individual countries and therefore lacks policy comparisons of the same measures in different countries.

In this study, we present a literature review of the existing scholarly discussion on the policy for reducing food waste in a systematic, transparent, and replicable way. We compared the major global policies to reduce food waste and make recommendations for improving them based on the Chinese context. We hope to systematically sort out China's food waste policies in different periods and make a comparative analysis of different countries' food waste reduction policies, so as to provide reference for developing countries to formulate food waste reduction policies and promote the realization of Sustainable Development Goals.

The contribution provided by this systematic literature review is threefold: firstly, this study will compare the major global food waste reduction policies and summarize the existing experiences; secondly, to propose recommendations to enhance the implementation of food waste reduction policies in China in the Chinese context; and finally, to advance the development of food waste reduction policies globally, especially in developing countries, and reduce the resource and environmental effects caused by food waste, thus promoting the achievement of sustainable development.

The subsequent sections of this paper are divided as follows: Sect. 2 describes the research methods used in this research; Sect. 3 analyzes the results of the study; Sect. 4 discusses the results of the study and discusses future research directions; Sect. 5 gives the research conclusions.

2 Materials and methods

To interrogate the extant literature in this area in a comprehensive manner, a systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (Li et al., 2022; Page et al., 2021; Petticrew & Roberts, 2006). While every effort is made to ensure that the most relevant studies are selected for the SLR, it is acknowledged some factors could limit the generalization this study's findings and analysis due to selection/exclusion criteria, research design, limited.

In our study, we first positioned relevant studies based on our synthesis objective, which was to compare global policies to reduce food waste. We first searched for peer-reviewed journal articles published in English and Chinese. Also, because policy materials involve many reports and online literature, we collected some of the "gray" literature through other methods and included it in our study. In fact, this gray literature provides a lot of valuable information.

The databases Web of Science, Scopus, and CNKI were used as a basis for the literature search. The initial key word search included the search strings “food waste” AND “reducing” AND “policy” as well as “食物浪费” AND “政策” AND “国际经验” in Chinese characters. At the same time, we searched part of the content through organizations, websites and reports (Table 1). Subsequently, the articles generated from the initial search were checked manually (mainly by reading through the abstract). We excluded studies that (1) studies involving only the quantification of food waste were excluded; (2) only empirical analysis of food waste is available and does not involve policy research; and (3) those involving only food loss not food waste (Table 2).

Table 1 Search strategy
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Table 2 Exclusion criteria
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According to the literature and reports we retrieved, we excluded the materials that were not relevant to our research content. A total of 78 articles were finally included in the research, including 63 literatures and 15 reports (Fig. 1). All the included information is described in the attachment.

Fig. 1
figure 1

Literature search chart

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While this paper has taken a global focus, we are more focused on how developing countries can learn from the advanced food waste reduction policies of developed countries. Therefore, in the final discussion section, we take China as an example and make corresponding suggestions based on national conditions by comparing global food waste reduction policies. This could be a potential avenue for further research on the factors that should be considered in the development of these policies and the effects of their implementation.

3 Result

3.1 National law documents

3.1.1 Focusing on food waste at a strategic national level

The initial measures, which were introduced in the International Agreement on World Food Security, were primarily aimed at food security. It was adopted by the World Food Conference in 1974 (Yang, 2001) and clearly stated the need to reduce food waste, achieve increased food consumption and reduce losses, and avoid a world food crisis. The Convention on Biological Diversity and the Rome Declaration on World Food Security, issued later, also had provisions for reducing food waste. After 2011, the United Nations began to expand the fight against food waste to the entire food chain. Several later documents have clarified the impact of food waste on the global economy, society, and the environment. The 2030 Agenda for Sustainable Development, adopted in 2015, also specifies a target to be achieved by 2030 against food waste. The EU has started to introduce a series of measures to reduce food waste in its member states after 2015 with the Circular Economy Package, including the EU Food Waste Measurement Methodology, and the Key Recommendations for Action of the EU (Garske et al., 2020), as well as the establishment of the "EU Food Loss and Food Waste Platform." European countries such as Germany and Norway have elevated the fight against food waste to the level of national strategies. Germany has made reducing or avoiding food waste a national task in its National Strategy to Reduce Food Waste in 2019. Norwegian Government's 2017 Food Waste Reduction Agreement specifies that all actors in the food supply chain and the Government must take responsibility for food waste. Many countries, such as the USA, Argentina, South Korea, and Japan (Table 3), have elevated the fight against food waste to a national strategic level and introduced relevant laws and regulations.

Table 3 Anti-food waste strategy level documents of the world's leading countries and institutions
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Thrift and diligence have long been traditional virtues in China; however, with the development of the economy, waste has become more severe. The Party and the State have noticed this problem, and Table 4 summarizes the relevant policy documents on anti-food waste since Economic Reform and Opening. The initial period was primarily for food loss and waste of party and government organs. Since the 18th CPC National Congress, President Xi Jinping has made many speeches and instructions on the issues surrounding food and beverage waste. Furthermore, anti-food waste has risen to the level of national strategy. The introduction of this stage has also expanded from the initial opposition to grain waste to the opposition to food waste (Zhao, 2020). The main body of anti-food waste has been expanding, from the initial party and government organs to all walks of life.

Table 4 Documents related to the anti-food waste in China
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3.1.2 Enactment of a single-line anti-food waste law

Currently, four countries in the world have introduced a single law with the primary goal of opposing food waste (Table 5) and consist of five laws concentrated in the European region. France was the first country to introduce an Anti-Food Waste Law. By comparing the anti-food waste laws of each country, the primary legal measures can be divided into punishment and encouragement. France, Spain, and China all have a legal policy based on punishment (Feng et al., 2022). In contrast, Italian law adheres to the principle of encouragement (Franco & Cicatiello, 2021). Regarding the specific content of the laws, France's Anti-Food Waste Law has explicit legal provisions for subjects in all parts of the food supply chain, with Italy's law primarily using incentives for food donations to reduce food waste. Spain's Anti-Food Waste Law requires all sectors of the entire food chain, from the primary or agricultural sector to the tertiary sector or retail and hospitality, to develop a reduction waste program. China's law focuses on food waste on the consumer side, and the main subjects are primarily catering service enterprises (Table S3).

Table 5 Comparison of single-line World Anti-Food Waste law
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We found that the focus on food waste reduction as an explicit national strategic goal and series of measures is mainly in developed countries, while developing countries are currently not paying enough attention to food waste reduction. The single law on food waste in China mainly focuses on the consumption end and pays less attention to the production end. Compared with developed countries, there are few incentive measures.

3.2 Food donations and food banks

3.2.1 Regulating and encouraging food donations

Food donation is one of the most significant measures to solve today’s food waste (Busetti, 2019; Kinach et al., 2020; Sundin et al., 2022). Developed countries such as Europe and the USA have comprehensive laws on food donation, and explicit provisions for possible disputes and liabilities (Eriksson et al., 2015; González-Torre & Coque, 2016; Vlaholias et al., 2015). Some countries have tax deductions for companies or individuals who donate food. A summary of the current food donation laws worldwide shows that the incentives for food donation are generally the same in all countries (Table 6), with "escape clause + tax incentives" comprise the majority of tax incentives. These policies have given a strong impetus to the Act of food donation. The models of food donation can be divided into advocacy donation, represented by the US model, and compulsory donation, represented by France. The only Chinese law regarding food donations is Article 23Footnote 5 of the Anti-Food Waste Law, and The Chinese Civil Code.Footnote 6 The Law on Public Welfare Donations make only vague references to donations of goods of all property types.

Table 6 Comparison of relevant national (regional, institutional) laws and regulations on food donation
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3.2.2 Food bank

Most food donations are distributed through food banks as a single organization. Food banks first originated in the USA to address the coexistence of waste and hunger. The world's first food bank was established in the United States in 19,676.Footnote 7 After more than half a century of development, there are now nearly 1,000 food banks worldwide and at least 400 charities worldwide. The Global Food Bank Network is currently the largest food bank organization, connecting and empowering food banks affiliated with regional and national food bank networks in more than 40 countries.Footnote 8 The main item distributed by food banks is food, but the USA, Canada, and other areas also distribute money or paraphernalia such as food stamps (Table 7).There are two main sources of donations to food banks, one is social donations and the other is government funding (Lambie-Mumford 2013; Warshawsky, 2011; Yadlowski & Theriault, 1998). The governments of USA and Canada provide funds to food banks in order to support their food purchases, and the US Department of Agriculture cooperates with food banks to promote certain projects. In terms of the role played by food banks, they play a significant role in assisting the disadvantaged and reducing food waste. Due to the traditional attitude of the Chinese, many needy groups will not go to food banks to receive help due to pride and dignity. Therefore, the Oasis Food Bank has innovated and developed the world's first online pilot food bank, where users in need can get help from food banks by placing orders for online delivery.

Table 7 Comparison of food banks in major countries around the world
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In general, food donation plays an important role in reducing food waste, and developed countries are quite complete in terms of specific requirements and exemption clauses for donations. As a major distributor of food donations, food banks are growing rapidly around the world and playing an important role in reducing food waste. China's food banks are still in the early stages of development, but their online distribution method is worth promoting.

3.3 Food recovery

Food waste recycling is also an important measure to reduce food waste. How to develop an effective food recycling framework has attracted wide attention from countries around the world. Korea has adopted a strict food waste charging policy for food waste. The Korean government has executed three methods of charging for food waste, which include Radio Frequency Identification (RFID) cards, prepaid garbage bags, and barcode management systems to reduce food waste. According to a study in Korea, the adoption of a measured food waste fee has reduced the amount of food waste generated in Korea by 300 tons per day. The US Environmental Protection Agency provides a food recovery hierarchy chart to address food waste, with favorite and least favorite options from the top to the bottom of the pyramid. These methods include "Source Reduction", "Feeding the Hungry", "Feeding Animals", "Industrial Use", "Vomposting" and "Landfill/Incineration". The EU has also made detailed regulations on the recycling hierarchy of food waste (Table S4). However, China has only made simple regulations based on the 3R (Reducing, Reusing, and Recycling) principle, and does not currently have a clear food recycling hierarchy. Although the policy of waste separation has been implemented, the food waste generated is not recycled sufficiently, and much of it is wasted. Developing countries, such as China, should focus on setting reasonable levels of food recovery and refining implementation measures in order to minimize unnecessary waste and greenhouse gas emissions, thereby contributing to the achievement of sustainable development goals.

3.4 Anti-food waste social governance

Food waste exists in the entire supply chain of food production and involves a variety of subjects. Therefore, to solve food waste, we cannot rely on the power of the Government alone but need the participation of multiple social subjects to solve the problems related to food waste.

3.4.1 Multiple subjects participation

Germany launched a "Too Good for Bins!" competition in 2012, which is for all companies, startups, tours, farms, research institutions, NGOs, and individuals to participate in a program of ideas and actions to reduce food waste. In the United States, the US Food Waste Challenge was launched in 2013 by the Agriculture and Environmental Protection Agency, calling on entities throughout the food chain, including farms, Agri-processors, food manufacturers, grocery stores, and tours. Norway established Matvett, a public interest organization that brings together food manufacturers, wholesalers, supermarkets, and consumers to reduce food waste by 12 percent between 2010 and 2015. In 2020, core members of the Norwegian food service industry launched the “Food Waste Reduction 2020" program”, which mobilized 50 percent of industry participants to join the effort.

3.4.2 Civic education

Household waste is the primary source of food waste (Dou & Toth, 2021); therefore, strengthening public education is a significant way to reduce waste. Italy, France, and other European countries have introduced food waste reduction into the classroom and used educational measures to raise students' awareness against food waste (Hou et al., 2018). Japan has enacted the Basic Law of Food Education to educate all citizens to value food and reduce waste. Germany has organized an annual nationwide "Save Food in Germany" awareness week since 2020. China also had several activities related to anti-waste including the so-called “Clean Plate 2.0 campaign”, to raise public awareness of the issue, cultivate thrifty habits and foster a social environment where waste is less acceptable and thriftiness is good, to prevent food waste.

3.5 Labeling of food dates

A study by the European Commission in 2018 showed that up to 10% of the 88 million tons of food waste generated annually in the EU is related to the date label (European Commission. Directorate General for Health and Food Safety. et al., 2018). Consumers determine whether food is ready for consumption by the expiration date on the food packaging. Globally, the terms used for food dates appear on food packaging (Table 8) and include "expired", "sell by", and "best before". This greatly confuses consumers and increases food waste; therefore, improving the consistency and clarity of food date labels can effectively reduce waste. Most countries have adopted laws and regulations to clarify the use of food label dates and circumstances (Weis et al., 2021). The US Department of Agriculture (USDA) unified food label dates as "Best if used by" in order to solve the confusion of food label dates and the waste caused by the public misunderstandings about food shelf life. At the same time, the definition also has actively strengthened public knowledge. In Denmark and the UK, social organizations actively cooperate with supermarkets in order to educate people about food shelf life. In China, the shelf life of food is uniformly marked on the date of labeling, but it is a broad concept of shelf life. Date labelling and shelf life standards for food are not specified in the law, resulting in the waste of much foods that could have been recycled and donated. There is a lack of relevant education at the social level, resulting in more food being wasted by Chinese families due to date.

Table 8 Comparison of the content of food date labels
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3.6 Data collection on food waste

Strengthening international cooperation and scientific research projects in food waste data collection has a very important role to play in reducing food waste. One of the critical shortcomings of food waste research is the shortage of food waste data (Fabi et al., 2021; Nicastro & Carillo, 2021b). Internationally, FAO has been collecting food waste data and has published in The State of Food Security and Nutrition in the World and Food Loss and Waste annually in recent years. The World Food Waste Index published by the United Nations Environment Programme (UNEP) is in collaboration with WRAP. The Report is the most authoritative and complete food waste data in the world. The UNEP and WRAP released the World Food Waste Index report and is the most authoritative and complete food waste data in the world. The EU makes explicit reference in the document to the establishment of a food loss and waste database and the EU common food waste measurement standards. The USA has also started collecting food waste data for quite a while, with the Department of Agriculture as the main body and various companies cooperating to collect relevant food waste data (Table 9). China's food waste data collection is abridged, and the majority of data used is China's food waste data collection which is extremely short. The database most commonly used is CHNS database (Min et al., 2021; Qi et al., 2021) and the China Restaurant Waste Report (Xu et al., 2020).

Table 9 Comparison of significant food waste databases
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4 Discussion

4.1 A comparison of global food waste policy experiences

Food waste management has implications in several policy areas including sustainable resource management, climate change, energy, biodiversity, habitat protection, agriculture and soil protection (Garcia-Herrero et al., 2018; Secondi et al., 2015). Policy-driven is the main measure to reduce food waste (Hamilton & Richards, 2019; Tang et al., 2022; Thyberg & Tonjes, 2016; Urrutia et al., 2019). One potential regulatory instrument is the review and elimination of unnecessary food safety standards that lead to high food waste rates. In comparison to fiscal and economic incentives, well-defined regulations seem to be a more effective tool to combat household food waste generation (Chalak et al., 2016). Following the introduction of the UN Sustainable Development Goals in 2015, several countries have elevated food waste reduction to the level of national strategies (Mourad, 2016). However, through our analysis, we found that most of them belong to developed countries at present, and developing countries are less concerned about food waste due to the existence of hunger and other phenomena.

Food sharing and food banks are a good solution to the problem of excess food and have a significant effect in reducing food waste (Capodistrias et al., 2022; Falcone & Imbert, 2017; Makov et al., 2020; Morone et al., 2018). Countries mainly use economic incentives for food banks, which include tax incentives and subsidies. Economic incentives aim to reduce food waste through costs or other market signals (Driesen, 2006). Exemption clauses are also important in the area of surplus food donations, and China's current legal policies are very lacking in this area, resulting in the current slow development of food banks.

The prevention and recycling of food waste contribute to a circular economy due to improvements in resource efficiency and energy recovery (Fujii & Kondo, 2018; Lin et al., 2014). Studies have found that sound food recycling policies can contribute to sustainable development, especially for developing countries (Fogarty et al., 2021; Fujii & Kondo, 2018; Lu et al., 2022a; Sarker et al., 2022). Our results found that Europe and the United States have a more rational food recovery structure with detailed rules for reducing food waste. In this regard, developing countries such as China need to learn from this, which currently has a shi'dian food recovery hierarchy in some cities.

Reducing food waste requires the participation of the entire community, information campaigns present one of the most widespreadtools used for food waste prevention and reduction (Priefer et al., 2016). Increased education of the population to reduce food waste is also very essential, such as cooking classes to help reduce household food waste (Mondéjar-Jiménez et al., 2016), and in some countries, food education has been added to the curriculum. Interventions that place a household's food waste level in relation to societal averages or a socially endorsed goal (bench marking) result in stronger norm activation (Porpino et al., 2016). Therefore, a culture of reducing food waste should be developed in the whole society, and there are still sectoral shortcomings in China in this regard.

Date labelling on packages is a key instrument of food policy, situated between production, retailing and consumption (Milne, 2012). Education about the meaning of date labels and efforts to improve the acceptability of imperfect foods (e.g., foods that are not fresh, unattractive, or close to their expiration dates) are also important measures to reduce food waste (Milne, 2012; Newsome et al., 2014). To prevent consumer confusion about expiration dates, a huge potential for reducing food waste lies in optimizing the labeling of prepackaged foods. There are a number of labeling technology innovations that can be adopted to reduce food waste.

Due to uniform food waste measurement standards and methods, there is less food waste data in the world, and it is especially difficult to collect food waste data for developing countries. In the future, it is necessary to further strengthen international cooperation to obtain food waste data in various aspects, to further measure the resource and environmental effects caused by food waste around the world, and to promote the process of global sustainable development.

We have compared current policies on food waste in countries around the world; however, there are many factors that influence the food waste phenomenon, and its policy development needs to take into account with national conditions in many ways (Morone et al., 2019a). For example, multinational companies and cultural industries can affect food waste, and in some countries, there are "food deserts" where hunger and waste coexist (Dagar et al., 2021). Therefore, we need to strengthen international cooperation and develop policies to reduce food waste according to local conditions.

4.2 Experience and inspiration for China

As the world’s largest emerging economy, China’s food security is of special concern, particularly because while it contains approximately 20% of the world’s population, China only encompasses 7% of the world’s arable land. Through the previous comparison of global food waste reduction policies, we found that there are still some problems in the process of policy development and implementation in China. Combining the current development situation in China and learning from foreign advanced experience, we propose the following recommendations to promote the implementation of China's food waste reduction policy, help “carbon neutral &carbon peak”, and to achieve sustainable development.

4.2.1 Improve the legal system against food waste and refine the norms for implementing legal policies

China has enacted several anti-food waste policies, and in 2021 introduced the Anti-Food Waste Law to elevates food waste to a national strategic level. However, laws such as the Anti-Food Waste Law do not specify how to enforce the law, define anti-food waste behavior, and punishment or reward. Meanwhile, China's laws and policies are primarily aimed at consumer-level waste, with little design for other stages of the food supply chain. First, the rules for implementing the law should be further improved. According to the specific situation in China and the international experience, specific measures and policies can be issued by localities, considering both penalties and rewards, stipulating wasteful behaviors of various subjects in the food supply chain, and specific implementation methods such as rewards and fines. Second, the collaboration among various departments should be strengthened to promote the implementation of relevant laws and policies jointly.

4.2.2 Formulate legal policies related to food donation and regulate the development of food banks

Food donation plays an essential role in addressing the issue of food waste and hunger at an international level. Article 23 of the Anti-Food Waste Law introduces the concept of food donation at the legislative level in China. China's food banks are in the early stages of development, and a single law cannot satisfy the establishment of China's food donation system and the development of food banks. It is recommended that food donation-related legislation should be introduced as soon as possible and that special legislation on food donation be considered, which is a single law regulating food donation and specifies the donation process and exemption measures of the law. Increase tax incentives, propose to revise relevant tax regulations, introduce relevant tax relief measures, and encourage enterprises, and individuals to donate food. The government needs to cooperate with non-profit organizations to build a food donation platform and strengthen the guidance for food banks to establish a food bank system with Chinese characteristics.

4.2.3 Establish a multi-level food recovery system to enhance the efficiency of food recovery and reuse

First, focus on multiple measures to reduce waste at the source. Increase investments in science and technology to reduce food loss and waste in the post-harvest grain and food supply chain. In accordance with the South Korean garbage metering and charging model, a nationwide waste metering and charging pilot will need to be carried out. Domestic waste will be charged step by step, and relevant expired food donations will be collected. Moreover, all these steps will need to be taken in order to reduce food waste at the source. The next step is to recycle food. Following the international experience, food that is not fit for human consumption should be fed to animals. The waste separation system should be improved. Following the example of Germany, catering enterprises should install oil–water separation equipment, and provide waste oil, which can be used as industrial fuel, compost or biogas to generate electricity. Finally, the remaining food waste should be disposed of in a uniform "landfill or incinerator."

4.2.4 Engaging diverse social actors to make anti-food waste conscious

Food waste involves all subjects in the food supply chain and requires the concerted efforts of all community sectors to solve this problem. First, we should strengthen the publicity of green consumption, create a green living culture in the community, establish positive and negative models, and increase rewards and punishments. In addition, we also should strengthen publicity and education, carry out anti-food waste education in all classrooms, and guide social subjects to spontaneously carry out anti-food waste work. Finally, we should learn from overseas experience and carry out more a government-funded anti-food waste campaign attracting the participation of various social organizations.

4.2.5 Strengthen research projects and collect food waste data on multiple levels

The lack of food waste data is a major shortcoming of China's food waste prevention and control. A comprehensive collection of food waste data will help us to understand the food waste problem scientifically and systematically so that we can better implement relevant measures to solve the issue. It is recommended to strengthen the establishment of scientific research projects on food waste, integrate multidisciplinary research on food waste, and provide academic support for policies. Meanwhile, it is also recommended to strengthen the collection of food waste data, set up nationwide food waste data collection points, and mobilize universities, research institutes, local governments, and companies to collaborate and collect food waste data in a comprehensive and multidisciplinary manner in order to provide data support for the fight against food waste.

5 Conclusion

We compared global food waste reduction policies in terms of legislation, food donation, food recovery, social engagement, date labeling and data collection. We found that most countries have elevated food waste reduction to the level of a national strategy, while some have enacted one-line laws against food waste. Food donations and food banks are effective measures to reduce food waste, with the main policy being "exemptions + tax incentives". Because hunger is still a problem in some developing countries, food donation policies have been slow to spread in developing countries.

A multi-level food recovery system not only reduces unnecessary food waste, but also facilitates the development of a circular economy, reduces unnecessary greenhouse gas emissions, and thus promotes the achievement of sustainable development goals. Household food waste is a major contributor to the waste phenomenon, and increased education of residents, such as shelf life and cooking knowledge, is also an important means of reducing food waste. Strengthening international cooperation by collecting food waste data in a comprehensive manner is also an important goal for future research.

Our study also found that food waste policy development requires consideration of multiple factors, and the measurement of implementation effectiveness during implementation, especially for developing countries, is an important issue. Food waste is predicted to increase in the upcoming years as low- and middle-income countries become more wealthy (Barrera & Hertel, 2021; Gil, 2020). Most countries have policies in place to combat food waste, and these policies have had some effect. Developed countries are doing better at the level of legislation, leading social participation, and food donation. However, China's current anti-food waste policy is in its infancy and still has shortcomings.

China can improve its food waste policy in the future by refining legislation, guiding the development of food banks, promoting social governance, and strengthening scientific research projects. This will reduce food waste, reduce greenhouse gas emissions, and reduce the loss of resources and environment caused by food waste, thus advancing China's sustainable development process and contributing to the achievement of the UN 2030 Sustainable Development Goals.

In addition, establishing criteria to evaluate the actual effectiveness of different policies in order to develop the best measures against food waste is key to future anti-food waste policy research. The evaluation of policy formulation and implementation effects in developing countries will also be a focus of future country studies. In our future research, we will further assess the implementation effects of China's food waste policy and its impact on resource environment and sustainable development.