Evaluation of an enumeration method for Listeria monocytogenes at low contamination levels in cold-smoked salmon.
For the enumeration of Listeria monocytogenes in cold-smoked salmon, a sensitive enumeration method, based on membrane filtration followed by transfer of the filter on a selective medium has been recently developed (Gnanou Besse et al., 2004, A contribution to the improvement of L. monocytogenes enumeration in cold-smoked salmon. International Journal of Food Microbiology, 91, 119-127). The aim of the study was to assess the performance of this enumeration method through an inter-laboratory study, using cold-smoked salmon artificially contaminated at 2 different levels (approximately 0.6 and 1.6 log10 CFU g(-1)). A reproducibility standard deviation of 0.23 log10 CFU g(-1)and 0.15 log10 CFU g(-1) was obtained for the method respectively at the lower level and the higher level. Under certain conditions, the uncertainty of measurement can be derived from the method reproducibility standard deviation and was calculated to be 0.46 log10 CFU g(-1) for the lower contamination level and 0.30 log10 CFU g(-1) for the higher contamination level. These values can be considered as satisfactory for such low contamination levels.
Gnanou Besse
Nathalie
N
Agence française de sécurité sanitaire des aliments, Laboratoire d'Etudes et de Recherches sur la Qualité des Aliments et sur les procédés agro-alimentaires (23 avenue du Général de Gaulle, 94706 Maisons Alfort cedex), France. n.besse@afssa.fr
Beaufort
Annie
A
Rudelle
Sylvie
S
Denis
Catherine
C
Lombard
Bertrand
B
D000818:Animals; D019411:Clinical Laboratory Techniques / Q000592:standards*; D003080:Cold Temperature; D015169:Colony Count, Microbial / Q000379:methods*; D003257:Consumer Product Safety; D005506:Food Contamination / Q000032:analysis*; D006801:Humans; D015203:Reproducibility of Results; D012474:Salmon / Q000382:microbiology*; D017747:Seafood / Q000382:microbiology*; D012680:Sensitivity and Specificity; D012906:Smoke
D012906:Smoke