Does the way workplace canteens are managed influence users’ plate waste?

Abstract Background Plate waste (PW) is part of the food waste and is defined as the amount of edible food served not eaten. There are few estimates of PW in the food services, mainly in school canteens, where PW appears to differ depending on the provider. Our aim was to analyse the role of different canteen management in determining PW in three hospital canteens in Italy. Methods On 5 working days between August and September 2022, healthcare workers’ trays were photographed before and after meal consumption. We compared two canteens managed by an external catering service (EC) with one internally managed (IC). The two canteens with similar sample size had different management. A modified visual Comstock scale was used to assess the PW. The Carbon Footprint (CF), Water Footprint (WF), energy and nutrient content were estimated using the SU-EATABLE LIFE database and the Italian Food Composition Database for Epidemiological Studies (www.bda-ieo.it). Significance was set at p < 0.05. Results 1227 trays were analysed (1026 in EC; 201 in IC), most of which contained no waste. The percentage of trays with leftovers was higher in EC (34%) than in IC (21%), as was the mean amount of PW (104g EC vs 60g IC) (p < 0.001). The PW contained significantly more energy (125 kcal vs 73 kcal) and protein (6.0g vs 2.4g) and had higher CF (204 CO2eq EC vs 76 CO2eq IC) and WF (178 LH20 EC vs 75 LH20 IC) in CE than in IC. The significance was confirmed independently to the sample size of the canteens, and when the analysis was repeated and only the first access of each user was considered. Conclusions Results suggest that an internally managed canteen produces less leftovers than a canteen operated by an external provider. This could be because an internally managed canteen is more adaptable to users in terms of food offerings and portion sizes, despite a smaller number of food options. However, further studies are needed to confirm our findings and to identify the causes of PW in food service. Key messages • Internally managed canteens seem to reduce plate waste, probably due to certain flexibility according to users’ plate waste. • Non-served food of the canteen should be estimated to confirm our data.