Résumé
Specific links between food waste and cities in a zero waste and circular economy perspective are analyzed by: i) reviewing high potential socio-technological innovations in food waste prevention and valorization ii) extracting research questions contributing to accompanying cities’ breakthrough strategies towards sustainable food systems. Based on the initiatives collected in the literature, 20 experts have extracted key measures expected to be particularly efficient in food waste reduction or valorization. These key measures are the following: 1) Education of public and professionals, 2) More flexible supply chain specifications, 3) Collaborative use of data, flow monitoring and smart sensors, 4) Regulation, taxation and financial tools, 5) Gradual withdrawal of food from market, stock clearance, on-site processing and donations, 6) Breakthrough manufacturing and packaging technologies, 7) Urban practices and urban planning, 8) Biomass valorization and biorefinery, 9) Fair distribution of responsibility between stakeholders. These key measures are analyzed according to a multi-criteria approach on the base of their expected high impact potential and transferability in many different settings. Numerous research questions addressing the food science community are also discussed; among them the question of downscaling is particularly relevant. This for logistic, where unconventional and short supply chains but also low scale reversed logistics (adapted both for collection of unsold food and of food waste) have to be developed. Dow scaling has also to be considered for processing, as small-scale transformations are required to face i) the new urban food practices such as note à note cooking, connected cooking, street food, etc., ii) the increase of new practices such as swap, urban gleaning, leftover cooking, collaborative and social solidarity food preparation actions, etc.) and iii) the development of flexible bio-refineries to transform locally produced bio-waste. Safety issues, which are particularly difficult to address in this new context of unconventional new food systems are highlighted.