WINTER BONUS MAGAZINE 2026

Milk flocculation Rosa Kirsten – Technical Advisor: Extensive Ruminant & Dairy Milk stability is a critical, yet often overlooked factor in dairy production, particularly in systems supplyingmilk for UHT processing. Whilemilk may appear normal under standard conditions, subtle imbalances in pH, mineral composition, diet, and environmental stress can compromise protein stability and lead to flocculation or alcohol instability. These challenges are increasingly observed in pasture-based systems where high potassium levels, rapid dietary transitions, and heat stress disrupt calciummetabolismand caseinmicelle integrity. Understanding the nutritional, physiological, and environmental drivers behind unstable non-acid milk is essential for maintaining processing qual- ity, protecting herd health, and ensuring optimal milk performance from farm to factory. Bodybuilders oftenmake milk flocculate on purpose Although casein is not the only component responsible for milk’s white appearance, it is the primary protein in milk and an excellent source of high-quality protein. Bodybuilders decrease the milk pH on purpose, thereby making the milk less stable. They do this by slowly adding distilled white vinegar until the pH drops to the point where it starts to flocculate, which is when the casein separates from the rest of the milk. This looks something like snowflakes floating in the solution. It is then poured through a cloth to separate the casein protein from the rest of the solution, slowly drying the casein protein in the oven, and then using it to make their protein drink. What is there to learn from them? The lower the pH, the less stable the milk is. It would not usually be a problem in the processing of milk, but with UHT processing, milk is increased to high temperatures and then decreased to low temperatures at a super high speed. Therefore, with UHT processing, any milk instability will be exposed. Illustration 1: Alizarol (75%) stability test of milk on the farm