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Abstract Landfilling wasted food (WF) is a significant source of greenhouse gas emissions. Anaerobic digestion (AD) is emerging as a promising alternative to jointly manage WF and generate bio-based energy, yet its widespread adoption is limited by transportation and operating costs. To reduce costs, AD facilities must be sited reasonably close to WF sources, energy transmission infrastructure, and available cropland for managing digestate, the liquid by-product from AD. Nutrient-rich digestate can displace synthetic fertilizer use on farms but can also runoff and create ecological risks, depending on location and application rate. Here, we introduce a multi-criteria geospatial model to assess the placement of future AD systems relative to (1) the distance over which AD feedstocks and products must be transported and (2) ecological risks created by land-application of digestate. Using Western New York State as a case study, we show that only 12% of land within the study area is suitable for siting AD systems. Further, the distance that digestate can be transported for land application is constrained to between 6 and 15 km to avoid exceeding crop nutrient demand. However, runoff modeling using the long-term hydrological impact analysis (L-THIA) tool showed that even sites with sufficient capacity to accept digestate could be sources of downstream water quality risk. This type of integrated analysis of ecological and economic constraints to AD siting is critical for sustainable food waste management strategies. 

Abstract The food industry consumes more than a third of all plastic packaging, much of which is discarded along with excess and wasted food. As the diversion of food waste (FW) from landfills to more sustainable disposal pathways like anaerobic digestion (AD) increases, food-associated plastics may follow, degrading to form microplastics (MPs) along the way. MPs pose a threat to ecosystems when digestate, the liquid residue of AD, is land-applied as fertilizer or sent to a wastewater treatment plant. To improve understanding of the prevalence, sources, and attributes of MPs associated with AD, we quantified and characterized MPs in liquid digestate from three full-scale digesters that vary in feedstock composition and digester operating conditions. MP abundance ranged from 400 to 25 033 particles L⁻¹across the three digesters with substantial variation in polymer type, color, and size. Polyethylene terephthalate and polyethylene fragments and films were most common. MP abundance and heterogeneity were higher where facilities accept FW from a greater number of sources. However, there was also variability in MP abundance and composition within each site, related to operational changes or disruptions. We estimated that at typical field spreading rates, approximately 2000–13 200 MP particles m⁻²may enter the environment per application. These results point to a need for improved separation of waste streams prior to AD, especially for facilities that accept organic waste from grocery stores and other post-consumer sources. 

Abstract Managing food waste (FW) by composting and anaerobic digestion offers potential sustainability benefits compared to conventional disposal practices. However, these processes can be unintended sources of plastic pollution to the environment, due to the presence of plastic contaminants originating upstream in the food system. During FW processing, plastic contaminants may partially degrade, ultimately leading to microplastic releases by way of agricultural use of compost and other bio-based products. Preventing and managing these releases requires a better understanding of the sources, magnitude, and nature of plastic contaminants traveling through FW management systems. This research collected representative FW samples from common generators, including restaurants, groceries, schools, and households, characterized the abundance, type, and material composition of contaminants present, and interpreted results through the lens of potential economic and ecological risks. Contaminants were observed in 80% of FW samples and were predominantly composite plastics, including multi-layer films, plastic-coated paperboard, and mixed polymer containers. The most common contaminants observed were fruit and vegetable stickers (30% by item count), but their small size and light weight make an insignificant contribution to total contaminant mass (<1%). The majority of contaminants were thin, flexible items, including plastic wraps, bags, gloves, and containers, which present added challenge to FW management due to the potential to impede mechanical equipment and reduce the production and quality of compost products. These results offer insights into potential strategies, including education, policy, and technology development, that can be leveraged across the FW management system to prevent contamination and improve food system sustainability. 

IntroductionThis project took a novel approach to reducing wasted food and improving food donation by prioritizing and centering the ideas and experiences of frontline grocery retail workers, who were integrally involved in each step of the research process. In this paper, we describe in detail the methods used in the Food Donation Champions Project, a worker-centered project in collaboration with a large US grocery retail chain. We provide the context, process, and lessons learned through our partnership with corporate leaders and frontline workers. MethodsThis project was conducted using a convergent, human-centered design process, involving design, public health, and anthropology research methodologies. The process involved six steps: planning, research, synthesis, ideation, prototype development and testing, and strategy finalization. We collected qualitative data through interviews and observations with grocery retail workers, members of corporate leadership, and stores' donation partners (i.e., food pantries and food banks). Frontline workers informed this research strategy and participated in all stages of analysis and strategy development. DiscussionThe process and findings described in this paper provide researchers and leaders in grocery retail a guide to a novel methodology and research approach that may be used to enhance projects that elevate the lived experience of people most central to addressing social and environmental problems. 

Abstract The United States food supply chain is a complex and critical network that links production to consumption, contributing to food access and security for people across the country and the world. In recent years, this network has faced significant shocks, including a trade war with China, the COVID-19 pandemic, and severe flooding and drought. While some studies have examined these impacts at the national or state level, there remains a very limited understanding of how the agri-food supply chain responded to these shocks at a finer spatial resolution. In this research, we aim to fill this gap by estimating the annual domestic agri-food flows in the US at the county spatial scale from 2018 to 2022. We analyze the spatiotemporal shifts in the food flow network and assess whether diversity in domestic trade mitigates the reductions in inflows during shocks. Our results show that significant spatial heterogeneity exists in commodity-specific responses to a shock. We also find that specific periods, which were beneficial to certain regions, could be simultaneously adverse to others. Moreover, we show that diversity in domestic trade plays a key role in minimizing inflows losses during a disruption. Our findings suggest that commodity-specific policies can be strengthened by accounting for regional socioeconomic and environmental conditions that shape network behavior during shocks. Furthermore, enhancing local diversification of inflows can make the food flows network more robust against disruptions. 

Abstract We investigate the subnational impact of trade on water use in the contiguous United States (CONUS). We develop an econometric model employing the instrumental variable (IV) approach to understand the causal impact of previous-year trade on current-year water use. Specifically, our analysis focuses on irrigated area and irrigation water use by water source (surface, groundwater, and total) across states in the CONUS for 2012–13, 2017–18, and 2022–23. We find that at the subnational scale, trade openness reduces groundwater withdrawals during droughts; a unit increase in previous-year trade openness results in a 2%–2.5% and 1.4%–2% reduction in groundwater irrigation withdrawals during 2012–13 and 2022–2023, respectively. This effect is identified as being driven by reductions in irrigated area and shifts towards advanced irrigation technologies. These findings enhance our understanding of how trade influences water use at the subnational scale and may provide helpful insights to policymakers. 

Abstract This study provides theoretical and experimental evidence that consumers adjust their premeditated food waste by date labels and their risk and loss preferences. The “Use by” date label leads to more premeditated food waste than “Best by” for deli meat and spaghetti sauce. However, changing date labels may not lower premeditated food waste relative to no label at all. Greater loss aversion correlates with higher premeditated food waste regardless of date labels and products. For participants with high loss aversion, they have higher premediated waste with no statistical difference in response for “Best by” and “Use by” labels. These results highlight the heterogeneous response to date labels. 

Abstract We contribute to the debate on trade and the environment by investigating the relationship between countries’ international trade and their groundwater use. We go beyond the virtual water literature that calculates the virtual water content of trade to assess how water use relates to international trade. We develop a suite of econometric regressions to account for the impact of trade liberalizations in a framework that includes standard determinants of countries’ water supply and demand. We focus on the agricultural sector and on the contribution of regional trade agreements (RTAs) to capture the impact of trade liberalizations. We find that more openness to trade due to an increasing number of RTAs may actually reduce total groundwater abstractions, which is qualified by countries’ comparative advantage. We do not find a statistically significant impact of trade on groundwater depletion, which also depends on the recharge rate of aquifers. Our analysis calls for assessing water use in a global world and in a framework that accounts for all the drivers of water use on the demand and supply side, including those behind international trade. 

PurposeFreezing extends the shelf life of food. Home freezing of fresh foods and the purchase of frozen foods have been advocated as approaches to reduce food waste in US households. This paper discusses how commonly US households apply these practices, quantifies frozen food waste and relates these practices to food waste. Design/methodology/approachWe add questions to the summer 2022 wave of the US Household Food Waste Tracking Survey. The novel survey data provide important baseline information and household behaviours, such as food waste, home freezing of fresh food and the purchase of frozen foods. We analyse the association among these behaviours from more than 1,000 US households. FindingsWe find that US household wastes about 26 g per person per week of food that was once frozen, which is about 6% of all household food waste. The finding indicates that a small portion of food waste in US households comes from frozen food. Vegetables and meats are the most commonly discarded frozen foods. Among the frozen items reported as discarded, about 30% were purchased as frozen rather than purchased fresh and then frozen at home by the consumer and about 30% more were reported as discarded from the refrigerator rather than directly from the freezer. The findings are important for informing strategies to reduce household food waste. Research limitations/implicationsWhile the data provide important baseline information and correlate the use of freezing with lower waste levels, more work is needed to understand if interventions encouraging frozen food purchase or home freezing would reduce household food waste. Originality/valueWe provide unique, detailed information about the quantity of frozen food waste in US households and the relationships between consumer food waste and the practices of frozen food purchasing and home freezing. 

Abstract Global agricultural trade, production, and harvested area have steadily increased between 1961 and 2021. In this paper, we construct, decompose, and compare various measures of global physical crop yield that rely on countries’ crop area, production, and trade weights that vary over time. We document how the composition of exports and imports irrespective of the particular drivers of globalization is skewed towards higher crop yields compared to the changing international patterns of countries’ production as evidenced by the distribution of harvested area and production. We also document how the physical yield of exporting countries has consistently surpassed that of importing countries, indicating as well how a globalized world in which countries can trade and alter the pattern of crop production offers a way to ensure that worldwide higher-yield crops are being consumed. As such, the increasingly globalized agricultural sector with its many drivers of trade substitutes for and/or complements efforts to close the yield gap by upgrading countries crop production methods. For the exercise, we use national-scale data for 60 years from the Food and Agricultural Organization of the United Nations.