Without a doubt, quality management is now a factor in success. Certification is standard practice. For laboratories this means that the correctness of the testing must be both guaranteed and reliably recorded. Muva inter-laboratory proficiency testing is extremely important for analytical quality assurance in laboratories throughout Germany, the rest of Europe and at an international level. Muva reference materials have been produced for long-term use and their basic parameters have been characterized in terms of the homogeneity and stability. Inter-laboratory proficiency testing and reference materials are increasingly becoming instruments for securing and developing research methods, both in laboratories and in production of dairy goods and other food stuffs.