The opportunity of tracking food waste in school canteens: Guidelines for self-assessment

Food waste generation and its industrial utilization: An overview

Food waste is produced for intended human consumption and is normally lost, discharged, contaminated, or finally degraded. The rising problem of food waste is increasing rapidly, so every sector is involved in minimizing food waste generation as well as waste management from collection to disposal, and scientists are developing the best eco-friendly and sustainable solutions for all sectors in the food supply chain, from the agricultural sector to the industrial sector and even up to the retailer to human consumption. Sustainable management is needed for the food wastes in the agricultural and industrial sectors, which are a major burning headache for environmentalists, health departments, and the government all over the earth. Various strategies can be employed to effectively control food waste, and these strategies can be ranked in a manner similar to the waste management hierarchy. The most desirable options involve the act of avoiding and donating edible portions to social agencies. Food waste is utilized in industrial operations to produce biofuels or biopolymers. The next stages involve the retrieval of nutrients and the sequestration of carbon through composting. The government implements appropriate management practices, laws, and orders to minimize food waste generation. Different contemporary methods are utilized to produce biofuel utilizing various types of food waste. In order for composting techniques to recover nutrients and fix carbon, food waste must be processed. Both the management of food waste and the creation of outgrowths utilizing biomaterials require additional study. This review aims to present a comprehensive analysis of the ongoing discourse surrounding the definitions of food waste, the production and implementation of methods to reduce it, the emergence of conversion technologies, and the most recent trends.

Reducing Plate Waste in Latvian Schools: Evaluating Interventions to Promote Sustainable Food Consumption Practices

Food waste (FW) threatens food security, environmental sustainability, and economic efficiency, with about one-third of global food production lost or wasted. Schools play a crucial role in addressing FW, representing lost resources and missed educational opportunities. The present research assessed three interventions to reduce plate waste (PW) in Rezekne City schools, namely (S1) a plate waste tracker, (S2) an awareness and educational campaign, and (S3) organizational changes, including larger plates, extended lunch breaks, and teacher supervision. Implemented in three schools with a fourth as a control, PW was measured at three intervals, at pre-intervention, short-term, and long-term post-intervention. The PW data analysis utilized two models (day view and class view) and a Wilcoxon signed-rank test. While the plate waste tracker initially reduced PW, sustained impact required continuous reinforcement. The awareness and educational campaign alone proved insufficient, highlighting the need for complex strategies. The organizational changes unexpectedly increased PW, underscoring FW's complexity. The research has concluded that reducing FW requires tailored and multi-faceted approaches. According to the MOA framework, the school catering model in Rezekne City lacks essential "Opportunities" for effective FW reduction, as students have limited flexibility in portion sizes and food choices, which hinders the interventions' effectiveness. Future research should explore adaptable FW-reducing interventions suited to specific school contexts.

Analysis of hotspots and emerging trends in school foodservice research using CiteSpace

BACKGROUND/OBJECTIVES

The school foodservice is a facility that offers catering services to students and exerts a significant influence on their well-being and academic performance. Hence, it is crucial to comprehend the present global research status and development trends of school foodservice over the last decade, investigate their future direction of progress and enhancement strategies, offer guidance to school canteen managers and policymakers, and foster the wholesome advancement of school foodservice.

MATERIALS/METHODS

The Web of ScienceTM (WoS) core collection was utilized as the data source to search for publications pertaining to the topics of school foodservices, school meals, and school foodservice/cafeterias. Subsequently, the CiteSpace software, a widely used tool for the visual exploration of scientific literature, was used for a visual study of the literature published on the topic.

RESULTS

A total of 1,500 papers published between the years 2013 and 2023 were selected from the WoS core collection and analyzed using CiteSpace. The research findings indicated that the primary areas of interest since 2013 in overseas research on school foodservice were centered around concerns regarding food quality, food waste, operational models including new methods and the correlation between coronavirus pneumonia and other related factors.

CONCLUSION

Future studies should focus on the utilization of emerging technologies, global efforts, and the development and implementation of policies and regulations on food safety in school foodservice. This will offer both theoretical backing and practical direction for advancing the sustainable development of school foodservice.

Global school plate waste estimates highlight the need for building a sustainable food education system

Food waste reduction is essential for supporting the sustainability of food systems. Wasteful behaviours are difficult to change after they have been formed, highlighting the importance of early interventions. Here we present an assessment of school plate food waste from 29 countries, and examine the environmental implications, causes, and interventions. School plate waste ranged from 4% to 46% per capita per meal and was positively correlated with country income levels. On a global scale, this waste embodies ∼150 Mha of cropland and ∼770 MtCO2e of greenhouse gas emissions; hence, reducing school plate food waste offers potentially large environmental gains. We propose a comprehensive, multistakeholder framework centred around sustainable food education that cultivates food systems knowledge and skills, and an appreciation for nature and food labour to reduce the psychological distance between youth and their food waste. To effectively implement the framework requires the support and engagement of families, communities and the broader society beyond the confines of schools.

The concept of food waste and food loss prevention and measuring tools

Food waste (FW) has become a global concern, with an estimated 1.3 billion tonnes lost annually, costing about $1 trillion. Environmental and social consequences of FW are significant, contributing to 6% of European Unions' greenhouse gasemissions and affecting global food security. FW occurs is a complex issue occurring at various stages of the food supply chain (FSC) and is influenced by multiple factors such as infrastructure, available knowledge and socio-economic conditions. Developed countries FW is more prevalent at the consumption stage, whereas in the developing countries losses occur in agricultural production, post-harvest and distribution stage. Accurate quantification of FW across the supply chain is crucial and monitoring key performance indicators helps identify areas for improvement. The European Union mandates FW measurement, aligning with sustainable development goals, emphasizing the need for effective waste prevention measures. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses approach was utilized to conduct a systematic literature review on FW key performance indicators (KPIs) and monitoring tools. The research identified 22 KPIs, categorized into three levels of the FSC: primary, secondary and tertiary. The most common KPIs included FW per capita, FW per portion and FW percentage. The study further discusses FW prevention measures and essential monitoring tools for addressing FW throughout the supply chain.

Effects of increasing the availability of vegetarian options on main meal choices, meal offer satisfaction and liking: a pre-post analysis in a French university cafeteria

BACKGROUND

Changing the food environment is an important public health lever for encouraging sustainable food choices. Targeting the availability of vegetarian main meals served in cafeterias substantially affects food choice, but acceptability has never been assessed. We examined the effects of an availability intervention at a French university cafeteria on students' main meal choices, meal offer satisfaction and liking.

METHODS

A four-week controlled trial was conducted in a university cafeteria in Dijon, France. During the two-week control period, vegetarian main meals constituted 24% of the offer. In the subsequent two-week intervention period, this proportion increased to 48%, while all the other menu items remained unchanged. Students were not informed of the change. Student choices were tracked using production data, and daily paper ballots were used to assess student satisfaction with the meal offer and liking of the main meal they chose (score range [1;5]). Nutritional quality, environmental impact, and cost of production of meal choices were calculated for each lunchtime. Food waste was measured over 4 lunchtimes during control and intervention periods. An online questionnaire collected student feedback at the end of the study.

RESULTS

Doubling availability of vegetarian main meals significantly increased the likelihood of choosing vegetarian options (OR = 2.57, 95% CI = [2.41; 2.74]). Responses of the paper ballots (n = 18,342) indicated slight improvements in meal offer satisfaction from 4.05 ± 0.92 to 4.07 ± 0.93 (p = 0.028) and in liking from 4.09 ± 0.90 to 4.13 ± 0.92 (p < 0.001) during control and intervention periods, respectively. The end-of-study questionnaire (n = 510) revealed that only 6% of students noticed a change the availability of vegetarian main meals. The intervention led to a decrease in the environmental impact of the main meals chosen, a slight decrease in nutritional quality, a slight increase in meal costs and no change in food waste.

CONCLUSIONS

Doubling availability of vegetarian main meals in a university cafeteria resulted in a twofold increase in their selection, with students reporting being more satisfied and liking the main meals more during the intervention period. These results suggest that serving an equal proportion of vegetarian and nonvegetarian main meals could be considered in French university cafeterias to tackle environmental issues.

TRIAL REGISTRATION

Study protocol and analysis plan were pre-registered on the Open Science Framework ( https://osf.io/pf3x7/ ).

From the shopping basket to the landfill: Drivers of consumer food waste behaviour

The EU, where nearly 57 million tonnes of food waste are generated annually, has set a target to halve this amount by 2030. However, the amount of food waste produced varies greatly between EU countries. While several EU countries are far from reaching this target, the Czech Republic already meets it. Despite this, little to no attention is paid to Czech consumers' food waste behaviour. This study responds to the unfulfilled need by drawing attention to food waste and its reduction, and possibly even serving as a model example for the EU target. We identify key factors influencing food waste by conducting a survey with 1,551 respondents on stated preferences. The results using the PLS-SEM approach show that the price of food does not have as great an impact on the level of food waste as its characteristics or planning, which is part of consumers' purchasing behaviour. Furthermore, consumers' attitudes and awareness of food waste reduce food losses. The causes of food waste remain decidedly similar before and during the pandemic COVID-19, except that people paid more attention to food attributes during the pandemic. Product attributes are an essential part of decision-making, especially for women and people with higher levels of education. We conclude that it is desirable to sufficiently educate and teach consumers to properly plan their consumption and better estimate the amount of food needed when shopping, which should be a conscious decision rather than an impulsive one.

Institutional pressures for SDGs in Indian food supply chains

Purpose

This paper aims to analyze the influence of institutional pressures on Indian Food Supply Chain (FSC) actors’ intention to adopt strategies for Sustainable Development Goals (SDGs). By focusing on an agrarian state, this paper explores the prioritizations of SDGs by FSC actors and analyzes the relative impact of institutional pressures in adopting strategies for SDGs.

Design/methodology/approach

Quantitative data was collected using questionnaires from 303 respondents engaged in the food industry in an agrarian state in India.

Findings

The SDG prioritizations of FSC actors are evidenced using SDG models, thereby suggesting the presence of tradeoffs and synergies within SDGs in FSCs. By using institutional theory, this study defines the impact of sustainability drivers on Indian FSCs, and contrary to previous studies, normative institutional pressures are found not significant – this paper explicates the reasons for this.

Originality/value

Differing stakeholder groups and their prioritizations can result in ranking one SDG over another, thereby resulting in SDG tradeoffs. Such tradeoffs imply that the achievement of one SDG could negate the achievement of another SDG, and therefore, this study explicates the need for a holistic managerial approach to adopting SDGs.

Influencing across multiple levels: The positive effect of a school-based intervention on food waste and household behaviours

Changing consumer food waste-related behaviours is critical to meeting global targets of halving food loss and waste. This paper presents a food waste reduction intervention trialled in five Australian schools and explores its influence on food provisioning practices, changed behaviours and food waste. Consisting of a mix of educational, skills-based, and whole-of-school-events, the intervention sought to reduce food waste by encouraging students to be more involved at home in choosing and/or preparing food to take to school. Students reported greater involvement in the target behaviours and there was a reduction in avoidable food waste in participating schools. Utilising a multi-level perspective, this study demonstrates how food-related practices and behaviours emerge from the interactions of macro and meso-level factors and highlights the value of this perspective when designing food waste reduction interventions.

Plate Waste in School Catering in Rezekne, Latvia

This research was conducted within the framework of a research project aimed at detecting patterns of plate waste and developing recommendations for improving catering in seven schools in Rezekne city (Latvia) by a combination of observation, physical weighing, semi-structured interview approaches and statistical analysis of variance (ANOVA). We identified plate waste (including wasted beverages), which remains after the lunch of schoolchildren in grades 1–7, examining a total of 7064 lunch samples. The originality of the research is due to the fact that a unified menu was designed for the field study, which ensured the same field study conditions in all the schools. The results of the research revealed that the average weight of plate waste per schoolchild reached 178 g, and the total weight of plate waste accounted for 28.75% of the total weight of food served. No significant differences in plate waste weight between various age groups and grades of schoolchildren were found, which was also confirmed by a one-way ANOVA test. An analysis of plate waste by food category showed that beverages accounted for the largest share of total plate waste (42.24%), followed by staple food (28.38%) and meat (11.77%). An analysis of plate waste shares of food served (%) by food category revealed a similar situation: the largest share of food served was made up of beverages (37.56%), followed by staple food (36.48%) and meat (28.77%). An analysis of the monetary value of food waste showed that the average cost of plate waste (excluding beverage) per schoolchild was EUR 0.236, which represented 16.6% of the national and municipal funding of EUR 1.42 per portion. Given the research results, the authors have concluded that in order to reduce the amount of plate waste generated by Rezekne city schools, school menus should be based not only on the requirements prescribed by relevant legal acts but also on cooking processes that meet the requirements of modern consumers (learners), e.g., by following trends in cooking practices in society to make the learners interested in consuming school food.

From evaluation to action: Testing nudging strategies to prevent food waste in school canteens

Food waste (FW) prevention is an essential measure to contribute to the achievement of the Sustainable Development Goal target 12.3, achieve more sustainable food systems and tackle the climate crisis. This paper aims at evaluating nudging strategies' impact on FW prevention in school canteens. To do so, it applies a four-stage methodology in 4 school canteens of the Metropolitan Region of Barcelona as case studies. This study has three main contributions. First, it provided real FW data by estimating a daily FW of 46 g per dinner. Secondly, it observed a 41% FW prevention impact when specific nudging strategies were applied. Dessert was the course with bigger reductions, especially when fruits were served. In addition, strategies involving canteen staff seemed to be more effective. Third, it proposed a methodological framework to co-design and evaluate the impact of FW prevention strategies by quantifying plate waste at school canteens. Thus, this study suggests nudging strategies as innovative interventions to improve food systems' sustainability by preventing FW in school canteens.

Are the Slimmer More Wasteful? The Correlation between Body Mass Index and Food Wastage among Chinese Youth

With the economic growth and living standard improvement, food waste has become increasingly common among Chinese youth. To test whether body size affects the food waste performance of youth, we examined university students as representative of the Chinese youth and conducted a large-sample survey in 29 universities across 29 provinces. Based on 9192 questionnaires collected from Chinese college canteens, we found that body size was correlated with food waste. The smaller the body mass index (BMI) value, the higher the likelihood of plate waste, the higher the amount of waste, and the higher the ratio of food waste. Heterogeneity analyses revealed that BMI exerted a more significant impact on males than females, as well as a more substantial impact on northerners than southerners. Robust tests using other proxies to measure body size, robust regressions based on the new adjusted samples, and robust tests with an instrumental variable to overcome the endogenous issue suggested that the slimmer participants tended to be more wasteful. Hence, this study confirms that the slimmer youth tend to leave plate waste and waste more food per capita per meal. This study is the first attempt to analyze food wastage from the perspective of BMI in China to our best knowledge, and it provides a unique viewpoint for understanding young people’s food wastage.

School canteens and the food waste challenge: Which public initiatives can help?

Foodservice is estimated to produce 12% of the total food waste in Europe, and it is a major target for policies against food waste. The amount of food lost during foodservice operations has been assessed in the literature as a figure ranging from 10% to 41% of the quantity prepared in the kitchen, either as non-served food or as plate waste. In this paper, a systematization of the current initiatives against food waste in EU school foodservice is provided. This background is used as a base to discuss the results of a direct assessment of food waste conducted in 78 primary schools in Italy, where 28.6% of the food prepared was not consumed by the diners. Part of it was saved for reuse, while the rest was disposed and treated as organic waste or, to a lesser extent, as unsorted waste. The flows of food waste, represented by a Sankey diagram, show that some actions may be implemented in order to save more food from disposal; for example, implementing donation programmes for non-served food or using doggy bags to avoid the disposal of plate waste. A greater effort shall be put on preventive actions, aimed at avoiding the generation of food waste; in this sense regular monitoring at schools may act as a first preventive measure as it can increase the awareness of students, teachers and foodservice staff over the issue of food waste.

Food Waste in Schools: A Pre-/Post-test Study Design Examining the Impact of a Food Service Training Intervention to Reduce Food Waste

This study aimed to assess change in school-based food waste after training and implementing the Smarter Lunchrooms Movement (SLM) strategies with school food service workers. This non-controlled trial was implemented in a random sample of 15 elementary and middle schools in a Community Eligibility Program school district in the Northeast, the United States. Baseline and post-intervention food waste measurements were collected at two different time points in each school (n = 9258 total trays measured). Descriptive statistics, independent t-tests, and regression analyses were used to assess SLM strategies’ impact on changes in percent food waste. The mean number of strategies schools implemented consistently was 7.40 ± 6.97 SD, with a range of 0 to 28 consistent strategies. Independent t-tests revealed that at post-test, there was a significant (p < 0.001) percent reduction (7.0%) in total student food waste and for each food component: fruit (13.6%), vegetable (7.1%), and milk (4.3%). Overall, a training session on food waste and the SLM strategies with school-based food service workers reduced school food waste. However, the extent of the training and SLM strategies to reduce food waste varied on the basis of the consistency and type of strategies implemented.

Analytical Assessment and Nutritional Adequacy of School Lunches in Sintra's Public Primary Schools

School meals present several cost benefits overtime at the short, medium, and long term for individuals and society. This cross-sectional study aims to analyse the nutritional composition and evaluate the adequacy of school lunches. One hundred and fifty-eight samples were collected and analysed from 10 primary schools in Sintra's municipality, served during one week. On average, energy (27.7% daily energetic requirements) and carbohydrate (48.1%) contents did not reach the reference values, and the content of protein (19.5%) exceeded the reference value (p < 0.05). The mean total fat (28.8%) and saturated fatty acids (5.4%) content complied with the recommendations. The mean salt (1.7 g) and dietary fibre (8.3 g) content exceeded the reference value but did not differ significantly from the recommendations. Addressing school canteens is crucial, not only in a nutritional approach, but also as an opportunity to achieve healthier, sustainable, and accessible food systems, aligned with the Sustainable Development Goals 2030. We highlighted the importance of evaluating evidence-based practices and disseminated practice-based evidence regarding the adequacy of school lunches.

Sustainable Agri-Food Systems: Environment, Economy, Society, and Policy

Agri-food systems (AFS) have been central in the debate on sustainable development. Despite this growing interest in AFS, comprehensive analyses of the scholarly literature are hard to find. Therefore, the present systematic review delineated the contours of this growing research strand and analyzed how it relates to sustainability. A search performed on the Web of Science in January 2020 yielded 1389 documents, and 1289 were selected and underwent bibliometric and topical analyses. The topical analysis was informed by the SAFA (Sustainability Assessment of Food and Agriculture systems) approach of FAO and structured along four dimensions viz. environment, economy, society and culture, and policy and governance. The review shows an increasing interest in AFS with an exponential increase in publications number. However, the study field is north-biased and dominated by researchers and organizations from developed countries. Moreover, the analysis suggests that while environmental aspects are sufficiently addressed, social, economic, and political ones are generally overlooked. The paper ends by providing directions for future research and listing some topics to be integrated into a comprehensive, multidisciplinary agenda addressing the multifaceted (un)sustainability of AFS. It makes the case for adopting a holistic, 4-P (planet, people, profit, policy) approach in agri-food system studies.

A systematic literature review on food waste/loss prevention and minimization methods

Several initiatives have been proposed to address food waste and loss issues and support stakeholders throughout the food chain. However, the literature still lacks a review paper that compiles methods, practices, and solutions to reduce food waste and loss. With the goal of filling this gap, this paper aims to compile and gather food waste and loss prevention and minimization methods to support decision-makers and other stakeholders along the food chain. Through a systematic literature review, we have outlined research findings and empirical studies on food waste and loss prevention and minimization methods previously published, studied, implemented, and discussed in the scientific literature worldwide. A sample of 84 articles was analyzed. As a result, this study provides a bibliometric analysis of the sample and a classification of the prevention and minimization methods found in the articles in 10 fields established by the authors. A coverage analysis of empirical studies was also performed, cross-checking the data with the type of food extracted from the case studies application. Lastly, suggestions of future research extracted from the articles were compiled into a research agenda to indicate trends and support academics, researchers, practitioners, and other stakeholders involved in the food chain to develop and study practices to minimize and prevent food waste and loss. The main contribution of this study is an inventory of the theoretical and practical methods of prevention and minimization of food waste and loss found in the literature, grouping them according to their similarities, to support stakeholders improving actions to reduce food waste in cities, farms, retail, and other sustainable ecosystems.

Promoting Food Waste Reduction at Primary Schools. A Case Study

Food waste (FW) has recently attracted the interest of different institutions and has been the focus of many studies due to its important environmental, social and economic impact. This paper aims to analyze whether a didactic intervention, consisting of informing teachers and pupils and involving pupils in reducing FW, could bring about changes in the level of knowledge and attitude towards FW and in the amount of FW generated during the mid-morning break and lunch at schools. This study was conducted at a public Primary School in Valencia (Spain). Subtle changes in the level of knowledge and attitude towards FW were detected in teachers and pupils after the intervention. Around 30% of FW reduction at lunch was observed in the intervention group but not in the other groups. A decrease of almost half of the average weight was observed during the mid-morning break in the rest of primary groups. The results apparently show that addressing the FW issue in classrooms can have a very positive effect on children’s attitudes. As it is such a cross-cutting issue; it raises awareness about a large group of Sustainable Development Goals, and encourages these young citizens to make conscious decisions and to act responsibly.

Sustainability-Oriented Innovations in Food Waste Management Technology

Food is essential to our survival, yet the Food and Agriculture Organization of the United Nations (FAO) estimates that about 820 million people were undernourished in 2018. In this context, food waste generation is a particularly salient issue. Wasting food means missing opportunities to feed the growing world population and consuming scarce resources, such as land, water and energy used in the production, processing, distribution and consumption of food. Firms in HORECA (hospitality, restaurant and catering) represent a considerable share of total food waste and, more importantly, are characterized by an overall low sense of awareness about the sustainability-oriented innovation opportunities and challenges of minimizing food waste. This article draws on an in-depth case study to explore the use of technological advancements in downstream value chain. This case study draws on a tech startup providing services for HORECA companies to address a new way for companies to solve the food waste challenge. Adopting technological innovations to quantify and minimize wastage via collaborations with third-party companies can be a strategic and cost-effective way to supplement a company’s open innovation activities.

The Effect of the Perceived Utility of a Management Control System with a Broad Scope on the Use of Food Waste Information and on Financial and Non-Financial Performances in Restaurants

The purpose of this study is to analyse the effect of the perceived utility of a management control system with a broad scope on the use of food waste information and on financial and non-financial performances in restaurants. To collect data, a questionnaire was administered in Brazilian restaurants. Data from 206 restaurants were analysed with structural equation modelling, which was performed with SmartPLS software. The results reveal that a management control system of broad scope, which includes non-financial information, is oriented towards the future, and contains an external and long-term focus, assists in the use of information on food waste. In addition, the use of information about food waste by managers improves the financial and non-financial performance of restaurants. The study contributes to the literature by showing that broader information systems are effective in managing food waste, and they can also contribute to improving performance.

Food waste at school. The environmental and cost impact of a canteen meal

The challenge of increasing food demand due to population growth urges all stakeholders to act against food losses and waste, especially in light of their environmental, cost, and social impacts. In developed countries, awareness raising, and prevention are particularly important at the consumption level, where food waste mainly occurs. In this sense, public school canteens represent a unique setting, because of their capacity of conveying food habits, while sustainably managing available resources. This research assessed the environmental and cost impact of food consumption and wastage in public school canteens through a case study in Italy. It combined life cycle assessment, environmental life cycle costing, and quarter-waste visual methods. The functional unit was defined as the average meal provided by the catering service to 3-10 years old students. Primary data on type and amounts of purchased food, transport, and utilities consumption were provided by the catering service, while food waste assessment was performed in selected representative school canteens. Secondary data on background processes were mainly sourced from databases and literature. Food waste at schools represented 20-29% of the prepared meal, depending on students' age and seasonal menu. The global warming potential (GWP) of the average meal was 1.11-1.50 kg CO₂-eq, mostly due to the food production impact. The meal preparation had the largest impact on costs. When considering embedded impacts, food waste was responsible for 14-18% of GWP and 6-11% of the costs. The sensitivity analysis showed promising environmental and cost reductions by introducing changes in the meal composition and preparation.

A comparative experimental study of the anaerobic treatment of food wastes using an anaerobic digester with a polyamide stirring rake or a stainless-steel stirring rake

A low treatment capacity and unstable operation are the main drawbacks of the anaerobic digestion of food wastes. The present work improved the efficiency and stabilization of the anaerobic digestion of food wastes using digesters with a polyamide stirring rake (DPSR) and compared it to a traditional digester with a stainless-steel stirring rake (DSSSR). The DPSR had a higher reliability and produced 3.97 times the methane yield of DSSSR in batch experiments at high loading rates (105 VS/L). Uniform design experiments were applied to investigate the relationship between methane yield and the stirring factors of the DPSR. A regression analysis of the uniform design indicated that stirring factors synergistically affect methane yield. The experiment verifying the optimal conditions showed that in the DPSR with 82 r/min stirring intensity and 10 min/d stirring time, the first 20 days of methane yield (392.1 mL/g VS) achieved to 85.26% of the theoretically derived methane yield. In brief, in the anaerobic digestion of food wastes for high methane production and stable operation, the DPSR was more beneficial for the anaerobic digestion of food wastes than the DSSSR.