Household Food Waste from an International Perspective

The food waste debate has flourished during the last years, leading to an impressive increase in the number of scientific publications [...]

The food waste debate has flourished during the last years, leading to an impressive increase in the number of scientific publications. After FAO [1] stated that about onethird of the total food produced at the global level goes wasted, the topic has been given increasing attention, and it became a specific sub-goal of the SDG 12 of Agenda 2030. The most recent study published by UNEP [2] reported that globally around 931 million tons of food waste was generated in 2019, 61% of which came from households.
The European Commission has devoted much effort to this concern by financing large projects specifically dedicated to addressing the issue. The FUSIONS project (2013-2016) provided a comprehensive attempt of harmonized methodology that was largely integrated by the EC Delegated Decision (2019) [3]. Within this project was also published the first assessment of waste generated in the EU food supply chain, where households were found to have contributed to 53% of the total food waste production.
Actually, households are the stage of the food supply chain where the greater part of food waste is generated in absolute terms. Scientific research followed this evidence by rapidly increasing studies on the issue. If we select the words "household" AND "food" AND "waste" on Scopus and limit the research to social science, business, economics, and agriculture, which are the relevant subject areas to this Special Issue, we get a total number of 739 documents, observing a 10 times increase in published papers, grown from 14 in 2010 to 141 in 2020 (see Figure 1).
Searching in the Scopus database for "food waste" only and limiting the results to the same subject areas, the number of documents is quite impressive: 443 in 2010 and 1986 in 2020. However, if we go in detail into the different stages of the food supply chain, the figures of the related documents are not so high. Food waste in retail, for instance, shows a peak of 54 documents in 2019. The search for food waste in agriculture reports slightly larger numbers, but it is not possible to associate all these documents directly to the field production stage. Food waste at the processing stage shows lower figures; this can be attributed to the fact that it is the most difficult to analyze as its quantification depends on whether companies provide data or allow researchers to perform audits; on the other hand, there is not a compulsory law anywhere in the world that makes the auditing of or reporting on food waste mandatory for private companies. This is the reason why the food waste literature concerning this stage of the food supply chain is often associated with energy recovery and recycling, chemistry, or environmental science [4].
What are the reasons that caused such a predominant interest in household food waste? Probably its relevance to the quantity of food waste and the fact that household food waste is hardly recovered for other uses; thus, it is destined for the garbage bin most of the time. In other words, preventing food waste is the only mitigation measure of its impact, so analyzing drivers and causes is the first action to be run. What are the reasons that caused such a predominant interest in household food waste?
Probably its relevance to the quantity of food waste and the fact that household food waste is hardly recovered for other uses; thus, it is destined for the garbage bin most of the time. In other words, preventing food waste is the only mitigation measure of its impact, so analyzing drivers and causes is the first action to be run.
Nonetheless, other very practical reasons might motivate researchers' interest. Studying household food waste allows researchers a great autonomy: a simple questionnaire that might be run online, using free internet tools, allows creating and analyzing large datasets in terms of the range of data collected and sample size. The same autonomy is not possible for other stages of the food supply chain: retailers and canteens require an interaction with other stakeholders, which might hinder, slow down, or complicate data collection. This encourages the proliferation of questionnaire-based studies at the expense of other methods that might be more accurate in detecting behaviors and reliable quantities [5][6][7][8][9] but are known to be more expensive and "slow" [10,11].
However, despite the low predictive value of the questionnaires, they are able to detect respondents' sensitiveness to this problem, revealing the way people perceive themselves toward the food waste issue [12][13][14][15]. All these results might be able to feed awareness-raising campaigns and initiatives possibly able to change behavior at home [15][16][17]. There is a wide range of results related to the determinants of food waste at home, well summed up in the reviews of [18][19][20][21]; some key findings are recurrent, such as the role of household size and its correlation with waste quantities.
Despite the proliferation of household food waste studies, many of them have been produced by a relatively "small" club of countries, while little or no information is available about most of the other countries in the world ( Figure 2). Indeed, there is a high presence of literature generated in the so-called Global North and former BRICS-namely, advanced economies plus Brazil, China, India, and South Africa in our case. As Figure 2 shows, there is a large number of countries, especially developing economies, that report no studies (in grey) or just one (in light blue). Nonetheless, other very practical reasons might motivate researchers' interest. Studying household food waste allows researchers a great autonomy: a simple questionnaire that might be run online, using free internet tools, allows creating and analyzing large datasets in terms of the range of data collected and sample size. The same autonomy is not possible for other stages of the food supply chain: retailers and canteens require an interaction with other stakeholders, which might hinder, slow down, or complicate data collection. This encourages the proliferation of questionnaire-based studies at the expense of other methods that might be more accurate in detecting behaviors and reliable quantities [5][6][7][8][9] but are known to be more expensive and "slow" [10,11].
However, despite the low predictive value of the questionnaires, they are able to detect respondents' sensitiveness to this problem, revealing the way people perceive themselves toward the food waste issue [12][13][14][15]. All these results might be able to feed awarenessraising campaigns and initiatives possibly able to change behavior at home [15][16][17]. There is a wide range of results related to the determinants of food waste at home, well summed up in the reviews of [18][19][20][21]; some key findings are recurrent, such as the role of household size and its correlation with waste quantities.
Despite the proliferation of household food waste studies, many of them have been produced by a relatively "small" club of countries, while little or no information is available about most of the other countries in the world ( Figure 2). Indeed, there is a high presence of literature generated in the so-called Global North and former BRICS-namely, advanced economies plus Brazil, China, India, and South Africa in our case. As Figure 2 shows, there is a large number of countries, especially developing economies, that report no studies (in grey) or just one (in light blue). On the whole, the scientific debate is strongly lead by the US, UK, and Italy, at least in numerical terms. Among the countries that count more than 10 studies on household food waste, 12 out of 26 are from the EU, while most of the others are OECD countries (US, Canada, Australia, Norway, Switzerland) and 4 are former BRICS countries (Brazil, India, China, South Africa). Eventually, we have 32 studies reported in Scopus not fitting into one of the above country classifications, as well as Iran and Vietnam with 11 studies each ( Figure 3). Not surprisingly, the scientific production by country partially reflects the funding capabilities of a sponsoring country, which sees a predominance of EU, US, Canadian, and Chinese sponsors. The strict connection with the economic power of the countries and their wealth is probably applicable to all the scientific research, including other disciplines On the whole, the scientific debate is strongly lead by the US, UK, and Italy, at least in numerical terms. Among the countries that count more than 10 studies on household food waste, 12 out of 26 are from the EU, while most of the others are OECD countries (US, Canada, Australia, Norway, Switzerland) and 4 are former BRICS countries (Brazil, India, China, South Africa). Eventually, we have 32 studies reported in Scopus not fitting into one of the above country classifications, as well as Iran and Vietnam with 11 studies each ( Figure 3). On the whole, the scientific debate is strongly lead by the US, UK, and Italy, at least in numerical terms. Among the countries that count more than 10 studies on household food waste, 12 out of 26 are from the EU, while most of the others are OECD countries (US, Canada, Australia, Norway, Switzerland) and 4 are former BRICS countries (Brazil, India, China, South Africa). Eventually, we have 32 studies reported in Scopus not fitting into one of the above country classifications, as well as Iran and Vietnam with 11 studies each ( Figure 3). Not surprisingly, the scientific production by country partially reflects the funding capabilities of a sponsoring country, which sees a predominance of EU, US, Canadian, and Chinese sponsors. The strict connection with the economic power of the countries and their wealth is probably applicable to all the scientific research, including other disciplines Not surprisingly, the scientific production by country partially reflects the funding capabilities of a sponsoring country, which sees a predominance of EU, US, Canadian, and Chinese sponsors. The strict connection with the economic power of the countries and their wealth is probably applicable to all the scientific research, including other disciplines and topics. Looking at the sponsors, it is clear that the top 15 contributors are basically supported by public funding, especially the EU, China, US, and Canada, followed by UK and Norway (Figure 4).  Thus, on the whole, the debate about household food waste seems to be strictly related to the availability of a country's financial resources for research funding. For a decade and based on [1], it has been thought that developing economies have less household food waste than developed economies and more post-harvest food loss due to lack of infrastructure. While this is partially true, it is necessary to remind ourselves that developing economies have a wide variety of differences in food culture, food availability, and inequality in food access and consumption, both among and within them; for instance, Soma et al. [22,23] found that Indonesian households have alarming data on food waste in certain strata of the population, characterized by geography, status, and income. The most recent UNEP report [2] highlighted this concept, showing that developing economies present household food waste data not dissimilar from high-income countries. The phenomenon of increasing urbanization, along with upper-income consumption patterns and changes in food habits, lead to the so-called nutritional transition [24]: this might increase the relevance of household food waste studies in developing economies, as food habits tend to present common features in urban areas around the globe.
For all these reasons, we decided to open a Special Issue on household food waste, trying to stimulate the contribution from less represented countries and with a variety of sub-topics admitted.
It has been an ambitious challenge, first because this is an open access journal, which foresees a fee that is not affordable in the same way for all countries. Another challenge we had to consider was our network: despite having contacts with many researchers all over the world, we realized how difficult it was to reach countries outside of the US, Canada, and Europe, as our research network is mostly based in the Global North as well.
In order to encourage studies from different countries, we also advocated the contribution of small case studies, qualitative approaches, and mixed methodologies; nevertheless, a prevalence of on-line questionnaire studies has been noted. COVID-19 has been a hindering factor for the application of different methods, as contacts with people have been forbidden during the recurrent 2020-2021 lockdowns (and lockdowns are still occurring at the time of writing this editorial), thus limiting the opportunities to enquire into the issue with other methods (diary, waste audits, ethnographic approaches).
Therefore, both from a geographical and methodological point of view, we did not collect the variety of studies we were aiming to, especially contributions from developing Thus, on the whole, the debate about household food waste seems to be strictly related to the availability of a country's financial resources for research funding. For a decade and based on [1], it has been thought that developing economies have less household food waste than developed economies and more post-harvest food loss due to lack of infrastructure. While this is partially true, it is necessary to remind ourselves that developing economies have a wide variety of differences in food culture, food availability, and inequality in food access and consumption, both among and within them; for instance, Soma et al. [22,23] found that Indonesian households have alarming data on food waste in certain strata of the population, characterized by geography, status, and income. The most recent UNEP report [2] highlighted this concept, showing that developing economies present household food waste data not dissimilar from high-income countries. The phenomenon of increasing urbanization, along with upper-income consumption patterns and changes in food habits, lead to the so-called nutritional transition [24]: this might increase the relevance of household food waste studies in developing economies, as food habits tend to present common features in urban areas around the globe.
For all these reasons, we decided to open a Special Issue on household food waste, trying to stimulate the contribution from less represented countries and with a variety of sub-topics admitted.
It has been an ambitious challenge, first because this is an open access journal, which foresees a fee that is not affordable in the same way for all countries. Another challenge we had to consider was our network: despite having contacts with many researchers all over the world, we realized how difficult it was to reach countries outside of the US, Canada, and Europe, as our research network is mostly based in the Global North as well.
In order to encourage studies from different countries, we also advocated the contribution of small case studies, qualitative approaches, and mixed methodologies; nevertheless, a prevalence of on-line questionnaire studies has been noted. COVID-19 has been a hindering factor for the application of different methods, as contacts with people have been forbidden during the recurrent 2020-2021 lockdowns (and lockdowns are still occurring at the time of writing this editorial), thus limiting the opportunities to enquire into the issue with other methods (diary, waste audits, ethnographic approaches).
Therefore, both from a geographical and methodological point of view, we did not collect the variety of studies we were aiming to, especially contributions from developing economies (see Table 1). Eight out of ten countries belong to the so-called Global North, with Brazil and Malaysia making exception. Five out of ten are questionnaire-based. For instance, Herzberg et al. [25] produced an impressive dataset on household food waste in Germany based on a diary study: 6853 households were surveyed between 2016 and 2017. The study proposes a type of digital diary, which is suitable for large scale samples-indeed, a good tool for EU countries that are requested to account for and monitor food waste at national scale. To our knowledge, this is the largest database on household food waste produced by a country that is based on a diary study. Other EU countries may be inspired by this opportunity in order to comply with their mandatory reporting.
Van Der Werf et al. [26] present a four-season waste characterization study of over 200 single-family households across eight neighborhoods in Toronto, which adopted a Pay as You Throw (PAYT) system. Results are a milestone since PAYT is increasingly being adopted in Europe and Italy as well, with the belief it can reduce waste and increase garbage separation. In this study, it clearly emerges that the second statement is true but not the first. Such a result should be debated with pros and cons of adopting a PAYT system and producing an evidence-based set of policy measures.
The third study we received was [27] from Malaysia, where a proxy was applied to the total quantity of waste collected before and during lockdown by the waste management company in town and district areas of the Klang Valley. Authors assume that a decrease of food waste is recorded along with a whole decrease of waste, proportionally. Despite being a risky hypothesis, it is true that no waste compositional analysis has been allowed anywhere in the world due to the COVID-19 pandemic, thus legitimating a speculation with available data. Future studies should be based on a waste compositional analysis if possible, or else other methods might be of help (mass balance or volumetric assessment based on separated fraction of food waste; interviews).
Pelau et al. [28] performed an analysis aimed at testing the hypothesis that the quantity of food waste of fruit and vegetables is influenced by the characteristics of the "national culture" according to Hofstede's theoretical framework [29]. In order to test hypotheses, two panel regression models were developed, where data were retrieved from FAO and Eurostat. Their results confirm that "national culture", according to Hofestede's definition, has an impact on the quantity of wasted fruit and vegetables. The analysis is one of the most original reads about food waste: a very different approach, one that was more qualitative, was adopted. Limitations of the study are briefly listed at the end of the article, and a question arises in the last sentence: "it would be interesting to analyze whether food waste is a matter of a natural born characteristic or if it can be re-educated in order to reduce the quantities of wasted food." It is not clear what the authors assume to be a "natural born characteristic", especially with reference to food waste, but further studies based on qualitative approaches are advocated by us too, perhaps focused on how to change social norms that might support food waste reduction at the collective and individual level.
Another group of researchers in Romania [30] present a study based on an on-line questionnaire that reached out to 2541 respondents. By using a K-means clustering model, they created three clusters: the "careless", the "precautious", and the "ignorant" (namely, those people who have not formed anti-waste habits), according to how much they declare to care about the issue, their daily actions in food waste management, and their perception of food waste being a problem for which they are responsible. This type of analysis (clustering consumers according to their answers to a questionnaire) is a kind of exercise that has already been proposed many times in the literature, see for instance [31][32][33].
The studies from [34] with reference to Japan, as well as [35] from Spain and [36] from Brazil, reported that the COVID-19 pandemic has had an influence on households' perception of food waste, where respondents declared that they have cared more about food waste during the lockdown. Previous studies demonstrated the same, such as [37][38][39]. On the one hand, these studies all rely on questionnaires, so distorted self-perceptions of respondents are possible [5][6][7][8]. On the other hand, all these studies let emerge a strong social norm, common to all these countries, which suggests that "wasting food is wrong", especially during an emergency situation.
Przezbórska-Skobiej and Wiza [40] surveyed the food waste behavior of two age-based classes of consumers in Poland, one mostly 19-26, the other mostly 35-50 (all respondents were students of their department): their results suggest that young people declare to waste more food than older people.
Last but not least, Keegan, E.; Breadsell [41] ran a study in Australia based on Social Practice Theory. They also involved the participants in the "Grow It Local" movement: Grow It Local seeks to engage the community in growing, sharing, and eating locally grown food. On the whole, 21 people completed food diaries (for two weeks) and 64 completed the on-line questionnaires. This study is particularly interesting since it starts to answer the question: Do people who grow their own food waste as much as people who do not? The answer seems to be that no, those who grow their food are more sensitive and actually waste less. Limitations of the study are again included in the sphere of self-reporting, despite the fact that diaries ensure a lower rate of self-reporting bias than questionnaires. However, this study asks a crucial research question about household food waste quantities in relation to sustainable practices of food purchasing, such those offered by Alternative Food Networks (AFNs), which is an important gap in the current literature [42]. After all, reducing food waste is part of creating sustainable food systems, and it is a component of the SDG 12: sustainable production and consumption. The mainstream approach adopted by research and policy making until now has split production and consumption in two parts, mostly focusing on (and blaming) the consumer for the second component [43,44]. A general lack of contestation to the current food provisioning regime is recorded in literature related to food waste, disconnecting the consumer from the surrounding economic context and thus limiting the real transformative potential of the alternatives [45]. Indeed, we hope that the study by [41] will be the first of a new series analyzing the relation between AFNs and household food waste.
It is clear that the food waste debate is highly centered in Europe and the Global North and that this feature might be nourished by both the wide acceptance in these countries of the publish-or-perish system and by the availability of public funding for research. Indeed, an important knowledge gap is noted for all the countries being outside this "club". Despite years of thinking that developing countries see their food waste happening most at the first stages of the food supply chain [1], recent studies are revealing different conclusions. Increasing urbanization [46] is leading to deep change in diets and food consumption habits [23], driven by the so-called "nutritional transitions" [24].
As outlined by [23], we need to rethink the food waste debate in developing countries and transition economies, as new consumption habits are leading to a higher food waste in urban areas, and we need to be particularly careful because some countries do not have efficient waste management infrastructures and services that are suitable for mitigating food waste impact, such as methane emissions. In the meantime, Global North countries need to harmonize the strengths for quantification through standardized methodologies that allow comparison and monitoring.
Another consideration is related to the mainstream narrative about household food waste: consumers seem to be analyzed out of their economic context, and they are framed as being entirely responsible for lowering food waste toward the SDG 12.3 [4,44]. How the consumer deals with organizing, planning, and cooking meals and managing leftovers seems to be at the core of food waste reduction at the household stage, based on the idea that food provision and consumption can be a perfectly rational act, disconnected from crucial external issues such as corporate marketing strategies, daily-life context, and social and psychological factors. Conversely, psychological factors influencing food-related actions are many [47] because shopping is neither a completely rational nor conscious process [48] and consumers are notoriously poor planners [49]. Any approach that requires the final consumer alone to address the systematic problem of over-production and overconsumption pushed purposively by the economic system [44] is not able to fully face the problem of household food waste. Therefore, our suggestion for future research in the field encourages studies based on holistic analysis of the food system, abandoning the sector-based approach that sees the final consumers as the undisputed stars of the household food waste solution. At the same time, food waste studies in developing economies, especially in urban areas, are particularly encouraged to fill the current gap of knowledge.
Author Contributions: Conceptualization, C.G. and S.F.; methodology, C.G. and S.F.; investigation, C.G.; writing-original draft preparation C.G. Review and editing, C.G. and S.F. Both authors have read and agreed to the published version of the manuscript.