The 24th Laboratory Performance Assessment in Fruits and Vegetables confirms:
QS-approved laboratories are reliable
Since 2006, QS has tested the analytical quality of QS-approved laboratories with the QS laboratory performance assessment twice a year. In each of the 24 tests that have been conducted by now, the test design has been modified and the laboratories were always confronted with new challenges. That pays off: The laboratories improve their analytical skills continually and demonstrate their reliability in the analysis of pesticide residues over and over again. This year’s spring laboratory performance assessment also confirms – you can count on the analyses results of QS approved laboratories in the residue monitoring. 54 of the 60 participating QS-approved laboratories passed the challenges successfully, 23 of them with maximum scores (cf. figure). This creates reliability for all market participants – both in Germany and in neighboring European countries.
As with the QS scheme participants, the group of laboratory participants is also international: Laboratories from 12 different countries took part in the most recent test - beside from Germany, mainly from Italy and Spain.
More and more companies from Southern Europe are opting for a QS participation. That’s why an accurate work of the laboratories is essential in these countries as well, explains Claudia Rotter, who is responsible for the laboratory approval at QS.
With their participation in the QS laboratory performance assessment, the laboratories demonstrate that they can perform their services sustainably and at a uniformly high level. Wilfried Kamphausen, Head of area Fruit, Vegetables and Potatoes at QS, knows:
There can be no doubt about the safety of fruit and vegetables from abroad. Meanwhile, there is a set group of foreign laboratories, which consistently perform high-quality results – an important contribution to ensure a comparable high level of production and marketing of safe fruits and vegetables transnationally. The fact that the laboratories are up to the challenges of the laboratory performance assessment and that even analytically demanding test matrices, such as the lemon used in this test, do not cause great difficulties, is shown by the current results.
Identification of the active substances without major difficulties
This time, the focus was on the detection of four post-harvest active substances and seven fungicides in the test matrix lemon. Two active substances were re-included in the test as they caused difficulties in the previous test. With tau-fluvalinate an active substance was included that has never been tested before in a QS laboratory performance assessment. The QS laboratory performance assessment is specifically designed to detect and eliminate weak points. Thus, the quality of the analyses is improved continuously, explains Rotter. This shows effect: The identification of the individual active substances causes nearly no difficulties for the laboratories. The metabolite prothioconazole-desthio, whose identification still caused some difficulties in the autumn test 2017 because it was not included in the test spectrum of many laboratories, was detected by all approved laboratories but one.
Reporting the results on the right track
The reporting of the individual requirement points has also improved markedly: 24 of the approved laboratories met all reporting requirements, 8 percent more than in the previous test. However, due to the large number of active substances there are consistently occurring mistakes which lead to devaluation. Therefore, the deficiencies will be addressed repeatedly at the meeting of laboratory managers in 2019 and are included in the revision 2019 as requirements for test reporting as an annex of the guideline residue monitoring.
High-quality pictures for download
Picture Credit: QS Qualität und Sicherheit GmbH / www.q-s.de