To enjoy the richness of the grazing cows and high yield during the summers, even during the winter, cheese has been the way to store milk for thousands of years. Nowadays yield is high all year around and the cheese production is possible during all seasons. The aim of this paper is to investi-gate how and why the seasons influence taste and texture of pressed and ripened cheese. Milk is composed of proteins, fat, lactose and water but contains also a lot of vitamins. The quality of milk is very important for the final constitution of cheese.

Bovine milk is an excellent source of bioactive peptides. The bioactive peptides are in an inactive state in the protein and are released during enzymatic activity, e.g. during cheese ripening. Specific properties of bioactive peptides from ripened cheese has been reported, e.g. antihypertensive, antioxidative, antimicrobial, immunomodulatory and mineral binding.

Today the milk production per cow is increasing but the milk delivered by the Swedish farmer contains less amounts of fat and protein than earlier. The contents have decreased since 1993. In average the milk contain 4,2 percent fat and 3,4 percent protein. Earlier the fat content in milk was important. Nowadays the dairy?s attention has turned to the milk?s valuable proteins, principally the Caseins, which have a considerable nutritional value and are important for several dairy products like cheese and yoghurt.

Concentration of protein in bovine milk is one of the most significant milk quality parameters, to a large extent determining the price for milk to the producer. Mastitis is a common disease among dairy cows, negatively affecting not only milk yield but also milk protein composition. Milk from mastitic cows tends to have lower cheese yield, negatively affected processability properties and sensory quality, due to changed protein quality and composition. Poorer milk protein quality would have an economically negative impact on dairy industry. Only few studies have investigated the short term effects of mastitis on milk protein composition.