Improving milk value chains through solar milk cooling

Publication Type

Working paper

Authors

Salvatierra-Rochas, A; Torres-Toledo, V; Mrabet, F; Müller, J

Year of publication

2018

Published in

ZEF Working Paper Series

Pubisher

ZEF Center for Development Research

Series/labeling

172

ISBN / ISSN / eISSN

1864-6638

Keywords

milk quality, solar energy

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.