Unveiling food waste in schools based on a low-cost and simplified approach to waste assessment

Public school feeding programs provide nutritional support to approximately 418 million children worldwide with an annual financial allocation of 48 billion dollars. Despite their significant scale, many developing nations, including Brazil, exhibit a notable deficiency in comprehensive data regarding food waste within educational establishments. Most of the food waste assessment methodologies present challenges to be widely adopted by schools, such as cost and time constraints. In response to this gap, the present study conducted a large-scale assessment of food waste across 20 educational institutions in Brazil with a student population of approximately 9000 individuals, utilizing a low-cost methodology, which encompasses management interviews and compositional analyses. This new and simplified methodological approach enabled the identification of food waste causes and confirmed that it occurs in both preparation and consumption stages, involving school management practices and student behavior. Instead of measuring the leftover food from each student's plate, this method conducts a compositional analysis of the cafeteria waste. Plate waste was estimated indirectly based on total waste collection and the daily number of students present. The findings revealed a significant disconnection between the perception of managers and the reality of waste generation: 65% of school managers did not consider food waste a relevant issue, despite the fact that 57% of organic waste is avoidable. The most commonly wasted foods were rice and beans, instead of fruits and vegetables, as expected by interviewees, with an average plate waste of 37 g per student. These findings underscore the need for schools to implement food waste measurement practices, enhancing managers' awareness and encouraging the adoption of prevention strategies. The proposed low-cost and non-intrusive methodology proved to be effective in bridging the knowledge gap in food waste assessment, especially in developing regions.