Resources, Barriers, and Tradeoffs: A Mixed Methods Analysis of School Pre-Consumer Food Waste

Background Food waste is a global problem. School food waste before the point of purchase, pre-consumer waste, has been little studied. Objective Our aim was to elicit a comprehensive assessment and understanding of preconsumer food waste amounts, behaviors, policies, and attitudes. Design This study used mixed methods, featuring a convergent parallel design using key respondent interviews (n=20) and 80 hours of structured kitchen observations, including food waste measurement. Participants/setting School and district kitchens (n=14) using stratified random sampling to ensure school level and kitchen type reflected the population of three Colorado school districts in 2016-2017. Kitchen managers, district-level nutrition services directors, and sustainability staff were interviewed. Statistical analyses performed Mean food waste volumes and percentages were calculated. Linear regressions were used to determine the relationship between school kitchen characteristics and food waste volumes. Interviews were coded to identify common themes. Results Trim waste and overproduction contributed the most to overall pre-consumer food waste; substandard foods and overproduction were the most common reasons for edible waste. Several competing priorities conflicted with schools' and districts' waste reduction efforts: food safety, promoting diet quality, food choice, and customer satisfaction. Batch cooking, production record use, shallow salad bar pans, and other inventory management techniques facilitated waste reduction. Staffing, space, and time constraints made it more difficult to implement these strategies. Increased food choice options were positively associated with pre-consumer waste volume (beta=49.5, P=0.04), and this relationship remained significant once regression models adjusted for district, salad bar use, and new menu items (beta=70.3, P=0.05). Conclusions School nutrition programs are complex, and a systems approach is warranted to reduce overall waste in the context of existing food safety and nutrition policies. More research is needed to elucidate the impact of food choice on overall food waste of the school meal system.