The ever increasing attention to and understanding for pollution problems by the public, as well as an intensive industrialization in the dairy industry by joining small production units, have made the traditional outlet of whey, such as return to the milk suppliers for cattle or pig feeding, as a fertilizer, or simply dumping it into the rivers or drains, very problematic. In the recent years it has therefore been necessary to find alternative uses for this product which has always been regarded as a waste product and treated accordingly. However, the dry matter contains components of high nutritive value and new techniques have made it possible to utilize these.

It is important that the whey is treated as a first class product, i.e. cooled and processed within few hours, otherwise it will not be possible to produce a first class product. Some of the processes are even impossible to perform, if the whey is of poor quality.

The composition of fresh whey from a conventional cheese production is approximately as follows:

approx. % of dry matter

Water

94.25%

Protein

0.80%

13

Lactose

4.30%

75

Ash

0.55%

10

Fat

0.10%

2

However, it is well known that the above mentioned composition changes to a great extent, depending on the type of cheese, use of different starter culture and different rennet type. Further, the milk composition, either due to seasonal variations or breed of cows, changes. This together with the fluctuating quantity available makes the whey problems even more difficult to solve.

Fig. 121 illustrates the various typical processes for treating whey. Furthermore, the spray drying of skim milk for later reconstitution for cheese production, see page 313, as well as spray drying of processed cheese, see page 319, are shown.

Processes for whey treatment
Fig. 121  Various processes for whey treatment