## 1 Introduction  
Materials, intended or not, for human consumption that are discharged, lost, degraded, contaminated, or eliminated from the food supply chain (FSC), as well as the previous or forward stages and operations are known as food loss (FL) and food waste (FW) [1]. According to the Food and Agriculture Organisation of the United Nations (FAO) [2], FL is defined as any kind of change in the availability, or the quality of edible material that prevents it from being consumed by people. Due to this, food waste can be a consequence of FL. Traditionally, FW was considered as the FL accrued at the retail and final consumption stages, so its generation is relegated to retailer and consumer behaviour [3]. Nowadays, the definition of FW also includes the losses incurred in the FSC stages or any other step of the agri-food industry, therefore it is defined as \"_any food and inedible parts of food, removed from (lost to or diverted form) the food supply chain to be recovered or disposed (including compost, crops plughed in/not harvested, anaerobic digestion, bio-energy production, co-generation, incineration, disposal to sewer, landfill or discarded to sea_\". The FSC begins, in any case, with the agricultural sector (farming) that produces by-product (i.e., manure, waffle, cornstalk) and FW and FL in the form of low quality products, damaged production, or products with no commercial value. Adequate products are used by the processing and manufacturing industry, where FL and FW are mainly generated within the entire process chain due to problems in storage, damages during transport, contamination along the process, or in separation stages that create by-products not intended for human consumption (i.e., feathers, skins, fruit peels... ) [4]. In the case of food markets and retail systems, FL and FW is generated in association with problems in storage, conservation, or unsold perishable products [3]. At the final stage of the product live cycle (end consumer), the FW is generated by a purchasing excess, over preparation processes, bad storage conditions, and other consumption behaviour patterns. It is estimated that around a 33% of all food produced worldwide is wasted globally in form of FW and FL [5,6]. Particularly the European Union (EU), 90 million tons of FW are generated annually [7]. That means that each European Citizen produces 76 kg of FW per year [8] only at household level, but if all the FSC is considered, then this number does increase up to 179 kg of FW and FL per capita [9]. This kind of waste production represents 12% of all the food entering a home [10], and a 25% of all the food of the FSC. This implies that within the complete FSC, 40% of FW, and FL occurs during postharvest and processing stages and another 40% during the retail and consumer levels. The generation of FW effectuates an impact in social, economic, and environmental spheres [1]. The most remarkable effects are environmental: for example, soil depletion due to landfill saturation, or the ground needs for agricultural raw materials and the consequent soil contamination. FW and FL also contribute to emissions of Green House Effect gases in transportation, storage and distribution operations, in landfill disposal due to methane emissions, or other disposal operations, such as incineration [11]. Social effects are related with ethical behaviours in terms of excessive resource consumption, and economic impacts may be ascribed to the costs that are related to food waste. Meaning that waste treatment methods for FW are currently evaluated, not only according to their treatment efficiency, but also in their environmental and social impacts [12]. Life cycle assessment seems to be a perfectly fitted tool for evaluating this determinants, especially environmental ones [13,14], such as carbon print, or its influence in climate change [15]. In this context, many legislative instruments arise to minimize the impact of FW.