This article presents the results of a collaborative study conducted to generate precision data for the revised International Standard ISO 11816-2|IDF 155-2, the fluorimetric method for the determination of alkaline phosphatase (ALP) activity in cheese.
The work was carried out by the European Union Reference Laboratory for Milk and Milk Products (EURL MMP) within the frame of the ISO/IDF Project Group on ALP activity in cheese (P06), of the Standing Committee on Analytical Methods for Processing Aids and Indicators (SC AMPAI), under the aegis of its project leaders Mrs. Nicolas and Ms Ghezzal.
This study, designed according to ISO 5725 parts 1 and 2, the protocol for interlaboratory method validation, involved a total of 17 laboratories and 8 cheese samples with ALP activities in the range of <10 mU/g to approximately 4500 mU/g. Relative Standard Deviations for repeatability and reproducibility varied by 3–6% and 8–13%, respectively.
The outcome of the study is compiled in this article. Data was incorporated into the
revised standard ISO 11816-2|IDF 155-2.
Keywords: Alkaline phosphatase, cow’s milk cheese, fluorimetric method, international collaborative study, enzyme, heat treatment, pasteurization validation, repeatability, reproducibility.