Organization of Proficiency Testing for Dairy Laboratories in Croatia, Bosnia and Herzegovina and Macedonia in Order to Improve Quality Assurance

Participation in proficiency testing is not only an obligation of all analytical laboratories which tend to be credible but also an opportunity to check how the results agree with the reference value. The Reference Laboratory for Milk and Dairy Products of the Dairy Science Department, Faculty of Agriculture University of Zagreb, is itself incorporated in the proficiency testing organized by dairy laboratories from Germany, Italy, France, Switzerland and Slovenia. The aim is to find out its own accuracy and reliability in particular milk and milk products analyses. On the basis of seven year experience of participating in proficiency testing, five years ago the Reference Laboratory started organizing its own proficiency testing for dairy laboratories in Croatia, Bosnia and Herzegovina and Macedonia for milk components such as milk fat, protein, lactose and somatic cells count. The results of the analyses have been statistically tested and, on the basis of Z-score, the successful measurements have been estimated. The aim of this paper is to demonstrate the organisation and data processing of proficiency testing for milk fat, protein, lactose and somatic cells count in milk for the involved dairy laboratories.