Reduce, Reuse, Recycle for Food Waste: A Second Life for Fresh-Cut Leafy Salad Crops in Animal Diets

SIMPLE SUMMARY: There is a historical link between co/by-products and animal feed, however innovative options are now available. Adopting the principles of the circular economy guarantees further progress for the food–feed chain. By-products and biomasses, such as former foodstuffs or plant by-products (PBPs) from the food processing industries, could be recycled as feedstuff for farms. This review focuses on the biomass derived from the processing of vegetables, and in particular on fresh-cut leafy salad crops as potential ruminant feedstuff. The chemical composition of this class of PBPs makes them comparable to other traditional feeds, such as fresh forage, and suggests that they could be considered for ruminant nutrition. Although at a very early stage, the potential of this new biomass seems high. These products can be used to reduce the environmental impact of both the food and livestock sectors. ABSTRACT: The world’s population is growing rapidly, which means that the environmental impact of food production needs to be reduced and that food should be considered as something precious and not wasted. Moreover, an urgent challenge facing the planet is the competition between the food produced for humans and the feed for animals. There are various solutions such as the use of plant/vegetable by-products (PBPs) and former foodstuffs, which are the co/by-products of processing industries, or the food losses generated by the food production chain for human consumption. This paper reviews the by-co-products derived from the transformation of fresh-cut leafy salad crops. A preliminary nutritional evaluation of these materials is thus proposed. Based on their composition and nutritional features, in some cases similar to fresh forage and grasses, this biomass seems to be a suitable feedstuff for selected farm animals, such as ruminants. In conclusion, although the present data are not exhaustive and further studies are needed to weigh up the possible advantages and disadvantages of these materials, fresh-cut leafy salad crops represent a potential unconventional feed ingredient that could help in exploiting the circular economy in livestock production, thereby improving sustainability.