Detection of Salmonella in food, feed and veterinary samples by EU laboratories

The European Union Reference Laboratory (EURL) for Salmonella organises interlaboratory comparison studies on bacteriological detection of Salmonella in different matrices (veterinary, food and animal feed) amongst National Reference Laboratories for Salmonella of the 27 European Member States (EU-MS). The EURL also gives non-EU Member States (EU candidate countries, member countries of the European Free Trade Association (EFTA) and third countries from outside Europe) the opportunity to participate in these studies. The objective of the studies is to test the ability of the participating laboratories to detect Salmonella at different contamination levels in the various matrices. In addition a comparison is made between the prescribed method of the food and animal feed studies (ISO 6579: RVS and MKTTn) and the prescribed method of the veterinary studies (annex D of ISO 6579: MSRV).This article describes the performance of the individual laboratories in the interlaboratory comparison studies as organised by the EURL for Salmonella in the period 2004-2010.The performance of the majority of the NRLs improved during the course of the studies. Overall the NRL laboratories performed well and were able to detect Salmonella in the different tested matrices. After improvement of the samples, it was possible to define criteria for good performance in the studies organised since 2006. In the eight interlaboratory comparison studies organised in the period 2006–2010, 15 laboratories found in total 19 deviations of which eight concerned a false positive blank result. The other deviations concerned sensitivity problems (false negative results). After checking and improving several technical aspects, the underperforming participating laboratories were able to improve their performance in a follow-up study.

Research Highlights
► Prescribed method for veterinary samples gave also good results in food matrices.
► Majority of the underperformances were caused by false positive blank results.
► Underperforming laboratories were able to improve after checking their procedures.