Microbiology proficiency testing schemes in wine

The number of laboratories performing microbiological analyses of wines has gradually increased in recent years over the world. However, the lack of regular proficiency testing schemes (PTS) in this field is an obstacle for the monitoring of the laboratory performance. The complexity of wine matrix in terms of bacterial ecology and biochemical aspects is a factor to be taken into account in developing a PTS, especially during the preparation of stable and homogeneous samples. Since February 2016, BIPEA set up tests on Brettanomyces analyses in wine, gathering more than 20 laboratories around the world. For each test, the statistical treatment of the data is performed according to ISO 13528. The assigned and tolerance values are calculated from the participants' data, and the performances of the laboratories are evaluated individually and collectively according to ISO/IEC 17043 and ISO/DIS 22117. The results obtained in these first tests are satisfactory with a progressive improvement of the dispersion of participants' results over the series. These data confirm that participating in a PTS is particularly important for the laboratories in order to assess and improve analytical performances and to obtain recognition of their analytical procedures by the accreditation bodies according to ISO/IEC 17025.