Mlijeko se smatra kompletnom namirnicom koja sadrži sve sastojke potrebne ljudskom organizmu. Ukoliko se mlijeko sterilizira može se dugo čuvati bez primjene niske temperature, zato je potrošnja sterilnog mlijeka puno šira nego pasteriziranog. Uobičajeno je sterilno mlijeko pakirati u hermetičnu višeslojnu ambalažu, ali trenutno je novost na tržištu sterilno mlijeko pakirano u boce od polietilena visoke gustoće (HPDE). Cilj rada je pratiti kakvoću sirovog mlijeka, te mlijeka nakon UHT obrade i aseptičnog punjenja u HPDE bocu. Tijekom 2015. godine praćena je kakvoća mlijeka i to: pH-vrijednost, točka ledišta, udio mliječne masti i udio proteina. pH – vrijednost svježeg sirovog mlijeka odgovarale su propisanim vrijednostima za svježe sirovo mlijeko. Udio mliječne masti u sirovom mlijeku bio je od 3,89 do 4,29%, a proteina od 3,08 do 3,50%. Visoka toplinska obrada (UHT) uzrokovala je pada pH – vrijednosti i porasta točke ledišta mlijeka. Proces automatske tipizacije mliječne masti u mlijeku je učinkovit i nema znatnih odstupanja od zadanih 2,8%, mliječne masti. Udio proteina u sterilnom mlijeku u HPDE boci približno je jednak udjelu proteina kao i u svježem sirovom mlijeku.

Milk is considered a complete food containing all the ingredients needed by the human body. If the milk is sterilized it can be stored for a long time without the use of low temperatures, so the use of sterile milk is much wider than pasteurized milk. It is common to pack sterilized milk in hermetic multilayer packaging, but the new product on the market is sterile milk packaged in high density polyethylene bottles (HPDEs). The aim of the paper is to monitor the quality of raw milk and milk after UHT treatment and aseptic filling in the HPDE bottle. During 2015, milk quality was monitored: pH, freezing point, milk fat and protein content. The pH correspond to the prescribed values for raw milk. Milk fat content in the raw milk was from 3.89 to 4.29%, and the protein content from 3.08 to 3.50%. UHT treatment caused the pH decrease and rising of milk freezing point. The automatic standardization of milk fat in milk is effective and there are no significant deviations of 2.8%. Protein content in sterile milk in HPDE bottles is approximately equal to the content of proteins in raw milk.