This invention relates to a method of producing powders and liquids containing milk proteins, which are stable in an acidic medium. In particular, the invention is concerned with a method of producing a powder which can be mixed with water, milk or juice to form a stable, acidified, high protein beverage. Moreover, the invention extends to a method of producing a carbonated, flavoured milk beverage or a carbonated, acidified flavoured milk beverage that is stable in an acidic medium. The invention also discloses methods of producing yoghurt style beverages and cream cheese by blending a stabilised acid component and a stabilised protein component to form an acidified protein component.