The management of staggering volume of food waste generated (∼1.3 billion tons) is a serious challenge. The readily available untapped food waste can be promising feedstock for setting up biorefineries and one good example is bread waste (BW). The current review emphasis on capability of BW as feedstock for sustainable production of platform and commercially important chemicals. It describes the availability of BW (>100 million tons) to serve as a feedstock for sustainable biorefineries followed by examples of platform chemicals which have been produced using BW including ethanol, lactic acid, succinic acid and 2,3-butanediol through biological route. The BW-based production of these metabolites is compared against 1G and 2G (lignocellulosic biomass) feedstocks. The review also discusses logistic and supply chain challenges associated with use of BW as feedstock. Towards the end, it is concluded with a discussion on life cycle analysis of BW-based production and comparison with other feedstocks.

Efficient and purposeful transport of food, from primary production to waste management, is essential to drive the necessary transition towards sustainable production and consumption of food within planetary boundaries. This is particularly the case for bread, one of the most frequently wasted food items in Europe. In Sweden, bread is often sold under a take-back agreement where bakeries are responsible for transportation up to the supermarket shelf and for the collection of unsold products. This provides an opportunity for reverse logistics, but creates a risk of inefficient transport that could reduce the environmental benefits of prevention and valorization of surplus bread. This study assessed the climate change impact of bread transport in Sweden and evaluated the impact of alternative food transport pathways. Life cycle assessment revealed the climate change impact of conventional bread transport, from bakery gate to waste management, to be on average 49.0 g CO2e per kg bread with 68 % deriving from long-distance transport, 26 % from short-distance delivery, and 6 % from waste transport. Evaluation of alternative bread transport pathways showed the highest climate savings with a collaborative transport approach that also reduced the need for small vehicles and decreased transport distances. The overall contribution of waste transport to the total climate impact of food transport was low for all scenario routes analyzed, suggesting that food waste management facilitating high-value recovery and valorization could be prioritized without increasing the climate impact due to longer transport. It has been claimed that conventional take-back agreements are responsible for most of the climate change impact related to bread transport, but we identified long distances between bakeries and retailers as the main contributor to transport climate impacts. © 2023 The Authors

Current understanding of food waste quantities in the Brazilian retail sector is limited. In order to develop efficient measures for food waste prevention and valorisation, reliable data on waste generation and composition are necessary. In this study, a compositional analysis of street market waste was conducted in São Paulo, Brazil. In total, 4.1 tonnes of waste were sorted into 27 waste fractions, categorised using a three-level approach. The average waste generation in the studied street markets was 23.7 kg per stall, of which 12.8 kg was classified as unavoidable food waste, 3.6 kg as packaging waste, and 7.4 kg as avoidable waste. The results show large amounts of unavoidable food waste, comprised of coconut, sugarcane bagasse, and peels. A large share of the avoidable food waste is comprised of single leaves, tomatoes, oranges, and bananas. Large variations were observed among the street markets analysed, both in terms of the food waste generation rate, and composition. The results from scaling up the data at the city level indicated a total wastage of 59,300 tonnes per year, of which 18,400 tonnes are classified as avoidable food waste.

The global food system is a major driver of many environmental impacts, particularly those related to climate change, biodiversity loss, and depletion of freshwater resources. These problems are aggravated by a substantial waste of food throughout the supply chain, where retailers are responsible for large quantities of waste. Although other parts of the supply chain account for relatively higher waste generation, retailers are particularly important because of their influence both downstream and upstream in the supply chain. 

This thesis aims to design and evaluate strategies for food waste prevention and valorisation, particularly for bread products, by analysing food waste quantities, identifying the causes and risk factors, and proposing and evaluating measures for preventing and valorising food waste.

This aim was achieved through a variety of approaches. First, food waste was quantified for one year in a typical mid-sized urban supermarket in Sweden. This information was used to identify hotspots at the product-level in relation to mass, environmental impacts, and cost. Bread was identified as a hotspot and also as a product with a high potential for waste prevention and valorisation measures. A second quantification was performed with the goal of estimating the quantity of surplus bread throughout the Swedish supply chain and to identify the risk factors for waste generation, particularly at the supplier–retailer interface. Finally, this thesis investigated current and future circular economy strategies for the prevention, valorisation, and management of bread surplus by evaluating the environmental performance of multiple strategies and comparing them with current waste management practices. 

The results from the first quantification indicated that bread was a category with significant contribution in all environmental impact categories analysed, with the greatest contribution in terms of the total mass of waste and the economic costs incurred by the supermarket. The second quantification estimated 80 500 tonnes of bread waste/year in Sweden, equivalent to 8 kg per person/year, which was mainly concentrated at household and retail levels, specifically at the supplier–retailer interface. The results provided evidence that the take-back agreement between suppliers and retailers is a risk factor for high waste generation. Therefore, current business models may need to be changed to achieve a more sustainable bread supply chain with lower waste generation. However, the currently established return system between bakeries and retailers enables a segregated flow of bread waste that is not contaminated with other food waste products. This provides an opportunity for alternative valorisation and waste management options that are not viable for mixed waste streams.

The results from the environmental assessment for the prevention, valorisation and waste management pathways supported a waste hierarchy, where prevention has the highest environmental savings, followed by donation, the use of surplus bread as animal feed, and for beer and ethanol production. Anaerobic digestion and incineration offer the lowest environmental savings, particularly in low impact energy systems. The results suggest that Sweden can make use of the established return system to implement environmentally preferred options for the management of surplus bread.

The use of food waste as feedstock in the manufacture of high-value products is a promising avenue to contribute to circular economy. Considering that the majority of environmental impacts of products are determined in the early phases of product development, it is crucial to integrate life cycle assessment during these phases. This study integrates environmental considerations in the development of solid-state fermentation based on the cultivation of N. intermedia for the production of a fungal food product using surplus bread as a substrate. The product can be sold as a ready-to-eat meal to reduce waste while generating additional income. Four inoculation scenarios were proposed, based on the use of bread, molasses, and glucose as substrate, and one scenario based on backslopping. The environmental performance was assessed, and the quality of the fungal product was evaluated in terms of morphology and protein content. The protein content of the fungal food product was similar in all scenarios, varying from 25% to 29%. The scenario based on backslopping showed the lowest environmental impacts while maintaining high protein content. The results show that the inoculum production and the solid-state fermentation are the two environmental hotspots and should be in focus when optimizing the process. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Reducing food waste is necessary for achieving healthy diets and sustainable food systems due to its negative impacts on resource conservation, food security, and environmental, social and economic costs. This paper aim is to quantify the amount and types of food that is wasted by the consumers in different restaurant configurations. The second aim is to understand the reasons which lead them to waste food and the greenhouse gas emissions associated with the waste. To fulfil the aims, a mixed methodology was used, including primary data collection in restaurants for the quantification of food waste, interviewing consumers and staff, along with calculating the environmental impact from the waste using life cycle assessment. The results show that different incentives and levels of interaction in consumer’s choice of food types exert influence on plate food waste. When incentive and interaction are low, the amount of food waste is larger. It is the case of a la carte restaurants. The best performance in the restaurant categories was when both incentive and level of interaction were higher. Buffet where the consumers pay by weight, therefore, is the configuration that generates less food waste on the consumer's plate. The main wasted products are rice and beans, followed by beef, and then other carbohydrates. The life cycle assessment indicated a carbon footprint varying from 128 to 324 g CO2 eq./plate from the wasted food. The result of the interviews showed that the food waste on the plate is not visible to consumers, since in the majority of cases, they believe that their food waste on the plate in the day of the observation was an exception. There is a large potential to reduce food waste by giving consumers the possibility to influence the serving to get the right portion size. Also, to further emphasize this behaviour by creating incentives for consumers only to serve as much food as they actually eat.

Bread waste represents a significant part of food waste in Sweden. At the same time, the return system established between bakeries and retailers enables a flow of bread waste that is not contaminated with other food waste products. This provides an opportunity for alternative valorisation and waste management options, in addition to the most common municipal waste treatment, namely anaerobic digestion and incineration. An attributional life cycle assessment of the management of 1 kg of surplus bread was conducted to assess the relative environmental impacts of alternative and existing waste management options. Eighteen impact categories were assessed using the ReCiPe methodology. The different management options that were investigated for the surplus bread are donation, use as animal feed, beer production, ethanol production, anaerobic digestion, and incineration. These results are also compared to reducing the production of bread by the amount of surplus bread (reduction at the source). The results support a waste hierarchy where reduction at the source has the highest environmental savings, followed by use of surplus bread as animal feed, donation, for beer production and for ethanol production. Anaerobic digestion and incineration offer the lowest environmental savings, particularly in a low-impact energy system. The results suggests that Sweden can make use of the established return system to implement environmentally preferred options for the management of surplus bread.

This paper quantifies bread waste throughout the Swedish supply chain and investigates the loss rate of prepackagedbread products at the supplier-retailer interface. The goal is to understand the extent of bread waste inSweden and to identify risk factors for high quantities of waste at the supplier-retailer interface, in order toprovide information supporting waste prevention measures. The study uses primary data, in combination withnational statistics and data from sustainability reports and the literature. Primary data were collected from 380stores of a Swedish retail company and a bakery. Bread waste was calculated to be 80 410 tons/year in Sweden,the equivalent of 8.1 kg per person/year, and was found to be concentrated at households and in retail, specificallyat the supplier-retailer interface. The results provide evidence that take-back agreements between suppliersand retailers, where the retailer only pays for sold products and the supplier bears the cost of the unsoldproducts and their collection and treatment, are risk factors for high waste generation. Current business modelsmay need to be changed to achieve a more sustainable bread supply chain with less waste.