Despite the significant contribution of the dairy sector to global food systems, data on food loss during dairy farming and processing are scarce. This research aimed to quantify and understand the drivers, and strategies that prevent food loss and waste. Using a mixed-method approach combining quantitative (processor quantities and farmer estimates) and qualitative (interview) data, two New Zealand case studies (dairy farmers and staff who worked for a dairy processor) were assessed to estimate the quantity of milk solids lost, identify dairy disposal practices and examine drivers that incentivised waste disposal or prevention/recycling approaches. From this study, dairy food loss is not a sizable issue given the percentage of losses occurring (1.8% per farm, and 5.5% at the processor). However, when extrapolated to national milk production: a 1.8% loss of New Zealand dairy production is the equivalent annual production of 350,000 cows. Qualitative analysis associated four key drivers with the level of food loss: perceptions of food loss inevitability, economic pressures, strong inter-stakeholder relationships and risk mitigation strategies. Prevention and recycling decisions were enabled by the industry's cooperative structure and the high value of milk solids, for example, surplus milk was traded to other processors rather than put onto farmers to dispose of/use. However, this study found that participants were very limited in their recycling and disposal destination options. This exposed farmers and the processor to serious reputational (e.g. odour, wasteful perceptions) and biohazardous (e.g. animal disease, antibiotic resistance) risks. These findings highlight how supporting more equitable market power between farmers and processors prevents dairy food loss, and that farmers and processors require support to diversify end-of-pipe recycling options, and ultimately improve the sustainability of dairy supply chains.
O'Connor et al. (2026) studied this question.