TY - JOUR
T1 - Validation of a same-day real-time PCR method for screening of meat and carcass swabs for Salmonella
AU - Löfström, Charlotta
AU - Krause, Michael
AU - Josefsen, Mathilde Hartmann
AU - Hansen, Flemming
AU - Hoorfar, Jeffrey
PY - 2009
Y1 - 2009
N2 - Background: One of the major sources of human Salmonella infections is meat. Therefore,
efficient and rapid monitoring of Salmonella in the meat production chain is necessary. Validation of
alternative methods is needed to prove that the performance is equal to established methods. Very
few of the published PCR methods for Salmonella have been validated in collaborative studies. This
study describes a validation including comparative and collaborative trials, based on the
recommendations from the Nordic organization for validation of alternative microbiological
methods (NordVal) of a same-day, non-commercial real-time PCR method for detection of
Salmonella in meat and carcass swabs.
Results: The comparative trial was performed against a reference method (NMKL-71:5, 1999)
using artificially and naturally contaminated samples (60 minced veal and pork meat samples, 60
poultry neck-skins, and 120 pig carcass swabs). The relative accuracy was 99%, relative detection
level 100%, relative sensitivity 103% and relative specificity 100%. The collaborative trial included
six laboratories testing minced meat, poultry neck-skins, and carcass swabs as un-inoculated
samples and samples artificially contaminated with 1–10 CFU/25 g, and 10–100 CFU/25 g. Valid
results were obtained from five of the laboratories and used for the statistical analysis. Apart from
one of the non-inoculated samples being false positive with PCR for one of the laboratories, no
false positive or false negative results were reported. Partly based on results obtained in this study,
the method has obtained NordVal approval for analysis of Salmonella in meat and carcass swabs.
The PCR method was transferred to a production laboratory and the performance was compared
with the BAX Salmonella test on 39 pork samples artificially contaminated with Salmonella. There
was no significant difference in the results obtained by the two methods.
Conclusion: The real-time PCR method for detection of Salmonella in meat and carcass swabs was
validated in comparative and collaborative trials according to NordVal recommendations. The PCR
method was found to perform well. The test is currently being implemented for screening of
several hundred thousand samples per year at a number of major Danish slaughterhouses to
shorten the post-slaughter storage time and facilitate the swift export of fresh meat.
AB - Background: One of the major sources of human Salmonella infections is meat. Therefore,
efficient and rapid monitoring of Salmonella in the meat production chain is necessary. Validation of
alternative methods is needed to prove that the performance is equal to established methods. Very
few of the published PCR methods for Salmonella have been validated in collaborative studies. This
study describes a validation including comparative and collaborative trials, based on the
recommendations from the Nordic organization for validation of alternative microbiological
methods (NordVal) of a same-day, non-commercial real-time PCR method for detection of
Salmonella in meat and carcass swabs.
Results: The comparative trial was performed against a reference method (NMKL-71:5, 1999)
using artificially and naturally contaminated samples (60 minced veal and pork meat samples, 60
poultry neck-skins, and 120 pig carcass swabs). The relative accuracy was 99%, relative detection
level 100%, relative sensitivity 103% and relative specificity 100%. The collaborative trial included
six laboratories testing minced meat, poultry neck-skins, and carcass swabs as un-inoculated
samples and samples artificially contaminated with 1–10 CFU/25 g, and 10–100 CFU/25 g. Valid
results were obtained from five of the laboratories and used for the statistical analysis. Apart from
one of the non-inoculated samples being false positive with PCR for one of the laboratories, no
false positive or false negative results were reported. Partly based on results obtained in this study,
the method has obtained NordVal approval for analysis of Salmonella in meat and carcass swabs.
The PCR method was transferred to a production laboratory and the performance was compared
with the BAX Salmonella test on 39 pork samples artificially contaminated with Salmonella. There
was no significant difference in the results obtained by the two methods.
Conclusion: The real-time PCR method for detection of Salmonella in meat and carcass swabs was
validated in comparative and collaborative trials according to NordVal recommendations. The PCR
method was found to perform well. The test is currently being implemented for screening of
several hundred thousand samples per year at a number of major Danish slaughterhouses to
shorten the post-slaughter storage time and facilitate the swift export of fresh meat.
U2 - 10.1186/1471-2180-9-85
DO - 10.1186/1471-2180-9-85
M3 - Journal article
C2 - 19422711
SN - 1471-2180
VL - 9
JO - BMC Microbiology
JF - BMC Microbiology
IS - 85
ER -