Improving milk value chains through solar milk cooling

Smallholder dairy farms are the major providers of marketed milk in Kenya, producing one to ten liters per day. Due to this low production level, farmers are usually associated in cooperatives. Dairy cooperatives are responsible for collecting the raw milk from the members to supply bigger volumes to dairy plants or to the market. These farms and cooperatives are often constrained by minimal hygienic standards and the lack of cooling systems leading to high microbial contamination of the milk. Moreover, under warm climatic conditions raw milk can exceed the maximum bacterial count established by food safety standards. As a result of these factors, 20-30% of the milk is estimated to be lost. Therefore, the Institute of Agricultural Engineering of the University of Hohenheim has conceptualized a solar milk cooling system based on the use of conventional milk-cans in Tunisia. The adopted strategy aims to offer a solution that can be adapted to different farm sizes and milk collecting scenarios. The ice, produced in a solar powered freezer, is used in the milk cans, which were designed with an integrated ice compartment and an external removable insulation for an effective cooling. The solar cooling system was transferred from the Tunisian context and adapted to the primary milk production in Siaya, Kenya. Depending on the amount of ice used, the milk cans can be used to preserve milk quality for six to 16 hours. This technology offers steady ice production year round and assures the preservation of milk quality from the farm to the main collection center or the market. The gradual introduction of the technology provided an important upgrade to the current value chain. Furthermore, the solar powered milk cooling system showed great potential to make the dairy value chain more efficient in off-grid contexts by using clean energy.