For example, the production of 1 kg of some cheese varieties leads to the generation
of up to 9 kg of whey. Nowadays, more than 200 million tons of whey are generated
by the dairy industry globally each year, and this huge volume is increasing by about
2 percent annually. Historically, for the cheesemaker, this whey by-product represented a nuisance and the whey was therefore disposed of in the most economical
manner, which often included spraying it onto fields, discharging it into rivers and
oceans, and/or treatment by municipal sewage works.
Cheese whey contains about 20 percent of the total milk protein and almost 100
percent of the lactose in milk, the latter in particular making this dairy by-product
highly polluting (BOD > 35,000 ppm).
2, 3 Changes in environmental protection legislation, together with a recognition of the value of various whey components, notably the proteins, over the past 50 years have catalyzed a reassessment of whey and
its evolution from a waste by-product to a valuable raw material. Simple disposal of
untreated whey has been outlawed in many Western countries, and industrial-scale
manufacture of ingredients containing the various whey components has been made
possible by technological advances in processing technologies, notably membrane
technology and large-scale chromatography.
Whey powder manufacture and food safety hazard points
While environmental protection and recognition of the functional and nutritional value of whey components drove the reassessment of whey as a dairy waste
stream, the development of suitable cost-effective and industrially scalable processing technologies facilitated change. The ability to rapidly and economically process
huge volumes of whey and at the same time to efficiently extract valuable components was a game changer. Nowadays, in most Western countries and many developing economies, very little whey is disposed of as waste. Rather, it is processed into a
variety of value-added whey ingredients, isolates, and products. Figure 14 illustrates
Figure 1. The fate of whey in a modern dairy-processing facility highlighting the various ingredients and products derived from the whey raw
material and the processing steps involved in the transformation of the whey stream. The red box highlights the steps involved in concentrating and drying the whey into a simple powder. The blue box highlights more advanced processing involving demineralization of the whey
prior to drying into demineralized whey powder.
of total solids
matic Acid Urea Am- monia
vitamin B12 penicillin
of total solids
the various ingredients and products
possible through the modern transformation of whey and the processing
Simple dried whey powder is prepared by concentrating all the solutes
in the separated and pasteurized whey
stream (protein, lactose, minerals) using
reverse osmosis and falling film evaporation, and then dehydrating the concentrate, usually using a spray drier (Figure
14). The final dried powder contains
approximately 75 percent lactose, 10
percent protein, 10 percent ash (
minerals), and 4 percent moisture, and serves
as an economical skim milk powder
replacer in various food applications.
The unit processes used to manufacture
whey powder, while efficient and cost-effective, can create food safety hazard
points if not maintained, operated, and
Ideally, the whey raw material should
be separated and pasteurized, thereby
providing a “clean” input stream to the
reverse osmosis and evaporation plants.
Incorrect pasteurization (e.g., not reach-