From plate to waste: Composition of school meal waste and associated carbon footprint and nutrient loss

Food waste significantly impacts the environment and nutrient availability. In Sweden, public meals generate 33,000 tonnes of food waste annually, with elementary schools contributing 9,200 tonnes. A composition analysis of plate waste from 4913 meals in two elementary schools in Uppsala, Sweden identified the wasted food components and quantities. This assessment aimed to gauge the embedded climate impact and nutrient loss. Findings revealed a carbon footprint of 1.0 kg CO2e/kg plate waste. Despite staple foods (potatoes, pasta, rice) being wasted the most (59 %), meat waste constituted the largest portion of the carbon footprint (61 %), despite being wasted the least (10 %). Plate waste was nutrient-dense, containing 4.8 MJ energy/kg and significant levels of protein (57 g/kg), and fiber (19 g/kg). To enhance the sustainability of school meal programs, tailored food waste prevention strategies in Swedish school canteens are recommended to mitigate their environmental impact and preserve valuable nutrients for children's nourishment.