At dairies, the reverse osmosis filtration technique is extensively used to remove water from milk to be used for further processing such as e.g. cheese or milk powder. However, many resources would be saved if it was possible to move this process to the farms, since you would reduce the amount of water transported.
In cooperation with the Danish dairy company, Arla, PhD student Ida Sørensen and Associate Professor Lars Wiking from Department of Food Science at Aarhus University have examined how milk quality is affected when concentrating the milk is carried out on-farm.
Ida Sørensen explains:
She continues:
No quality deterioration
The researchers at Aarhus University have analyzed experiments with both the so-called ultrafiltration, which is supposed be more gentle to the milk, and with the reverse osmosis technique, which requires a higher pressure on the milk but also retains the lactose which may be an advantage in for example milk powder. Neither the total bacterial count, or the FFA-levels nor the protein breakdown were negatively affected by reverse osmosis; the concentrated milk could very well be used for both cheese and milk powder.
Analyses also demonstrate that the quality and durability of milk powder made from concentrated milk is the same as for powder made from ordinary milk; in cheese, however, there is a minor difference as to how the enzymes react; and in the experiments, concentrated milk coagulated approximately ten minutes later than regular milk.
Significant interest -- but is it worthwhile?
Concentration of milk on the farm, or during transport from farm to dairy, is carried out in many other countries in the world, e.g. in Texas, USA, where both herds and distances are huge. Different models exist as to how on-farm milk concentration may become a reality. The farmer may buy the filtration equipment himself and achieve an additional price for the milk. Or perhaps the dairy could buy, maintain and service the filtration installation or it could be acquired through some kind of leasing agreement.
Herd size and distance to the dairy in particular, are of major importance when considering resources and profitability, as small installations typically use more power than one large installation, says Ida Sørensen; she has just presented the results of the studies at a major conference in Dublin.
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Facts about the project
"New sustainable milk concentration technology for dairy herds" is a five year project which ends this year. Project participants include Arla Foods amba/Arla Foods Ingredients PS (Arla), Danmarks Kvægforskningscenter (the Danish Cattle Research Center - DKC) and Aarhus University (AU). In addition, GEA Process Engineering (GEA) is affiliated as an external consultant.
The project is financially supported by Mælkeafgiftsfonden (Milk Taxation Foundation - MAF) and the Green Development and Demonstration Programme (GUDP).
Dairy Science & Technology