In the manufacture of most cheeses, typically less than 10% by weight of the original raw milk is used to make the cheese, leaving behind substantial quantities of a liquid known as 'whey'. The whey consists typically of water (~90%) and of other valuable nutrients such as serum proteins and lactose. Whey is a highly polluting substance due to its high BOD content and thus its disposal may cause an excess in oxygen consumption, eutrophication and toxicity.
Given its excellent nutritional properties, whey can be used in a number of food applications. This best practice outlines how cheese making producers can implement ways to recover whey and thus avoid the environmental impacts caused from its disposal.
The recovery of whey can be done in a number of different ways according to the following priority list:
- concentrate, filter and/or evaporate the whey to produce whey powder, whey protein concentrate (WPC), lactose and other by-products,
- manufacture whey products intended for human consumption such as whey cheeses or whey drinks,
- feed the whey to animals, use it as a fertiliser or process it in an anaerobic digestion plant.
This best practice it is broadly applicable to all cheese producers, provided that local conditions such as sufficient generation of whey for the implementation of a whey concentration system, market demand for whey-based products, availability of local livestock to feed, allow the implementation of the options listed above.