Introduction

In many countries, milk is exclusively produced by small and medium sized dairy farms with daily milk output below 200l. Their milk is in most of the cases transported to milk collection facilities without any form of cooling. In addition, lack of hygiene and cleaning procedures and problems with cattle health are the most common reasons of high bacterial growth during short-term storage of milk on the farm and during transportation. Under warm climatic conditions, milk can exceed the maximum bacterial count prescribed by food safety laws after about two to five hours. During the hottest periods of the year, lack of quality can lead to high rates of refused milk at collection centers or dairy plants. Furthermore, due to low production volumes, evening milk is often not collected year round, thus causing additional on-farm losses. Small-scale solar powered milk cooling technologies can support the milk value chain at farm, cooperative and collecting center level by increasing productivity and giving access to price premiums and to additional markets.