Alkaline phosphatase activity in cheese as a tracer for cheese milk pasteurization

Alkaline phosphatase (ALP) activity is used throughout the world as a marker for the proper pasteurization of milk, to guarantee its hygienic safety. The Standard ISO 11816-2/IDF 155-2 describes the analysis of ALP in cheese. However, the method has been questioned in the past because there have sometimes been ambiguous results. The critical operations of the analytical procedure are more precisely defined and a zonal cheese sampling adopted. ALP inactivation is firstly evaluated in the relevant steps of controlled cheese makings of hard (Emmental), semi-hard (Raschera) and soft (Chaource) cheeses. Application of the improved procedure in over 700 samples of typical cheeses from France, Italy and Switzerland proved the applicability of the method. Based on this large study, a limit for ALP activity in cheese from pasteurized milk is proposed at 10 mU/g.