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EU Interlaboratory comparison study animal feed II (2012) : Detection of Salmonella in chicken feed

EURL Interlaboratory comparison study on animal feed II (2012) : Detection of Salmonella in chicken feed


In 2012, it was shown that 30 of the 34 National Reference Laboratories (NRLs) for Salmonella in the European Union were able to detect the presence of Salmonella in chicken feed, at both low and high levels. Organizational problems meant that one of the remaining four laboratories was unable to process the samples that it had been sent. The other three laboratories reported false positive results (they detected Salmonella in blank samples). One of these three laboratories made an initial transcription error when processing the raw data, which led to it being rated as 'moderate'. The remaining two laboratories in this group also reported false positive results during the follow-up study. This was probably caused by cross-contamination during the proficiency test. Due to its consistently poor performance, one NRL was visited by EURL-Salmonella (a central coordinating body), which was able to identify various points for improvement. Depending on the method used, the laboratories detected Salmonella in 94 to 97 percent of the contaminated samples tested.

Interlaboratory comparison study obligatory for European Member States
These were the results obtained in the second interlaboratory comparison study on animal feed, which was organized by the European Union Reference Laboratory for Salmonella (EURL-Salmonella). The study was conducted in September 2012, with a follow-up study in January 2013. Within the European Member States, all NRLs responsible for the detection of Salmonella in animal feed samples were required to participate in this study. EURL-Salmonella is part of the Dutch National Institute for Public Health and the Environment (RIVM).

The laboratories used three internationally accepted analytical methods (RVS, MKTTn and MSRV) to test for the presence of Salmonella in samples. They were required to proceed in accordance with the study protocol. To this end, each laboratory received a package containing chicken feed (free from Salmonella) and a range of reference materials which were either Salmonella-free or which contained different levels of this bacterium. The laboratories were instructed to spike the chicken feed with the reference materials before taking samples for testing. The use of Lenticule discs as reference material gave good results in both the food and veterinary studies.

MKTTn analytical method significantly superior
This study's results underscore the benefits of using more than just one analytical method, as MKTTn delivered significantly better results than RVS and MSRV in terms of detecting Salmonella in chicken feed. This is in contrast to earlier studies in which other "products" were analysed, such as minced meat or another type of chicken feed.

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