Veld PH in 't ,
Hoekstra JA ,
Strijp-Lockefeer NGWM van ,
Notermans SHW
77 p
in Dutch
1992
Toon Nederlands
English Abstract A trial with 42 laboratories participating, was
organized in May 1990 to test the L.monocytogenes reference materials in
combination with reference materials containing competitive microorganisms.
The materials were tested by 2 methods, one standardized for all
laboratories (SM method) and the other method chosen by the laboratories
themselves (OWN method). Thirty samples were tested by each method of which
nine were negative for Listeria. The contamination level of the
L.monocytogenes capsules was 4.9 cfu/capsule. Each laboratory was
expected to find the organism in 18 or more out of the 21 L.monocytogens
contaminated samples. The total contamination of microorganisms was 2.9 x
10-4 cfu/capsule. Using the standard method Listeria monocytogenes was
detected in 79.3% of the contaminated samples, and 45% of the participating
laboratories made the expected number of isolations. With the OWN method
these percentages were 78.1% and 52.5% respectively. Concluded was that
the materials tested are suitable to test the performance of the detection
method for Listeria in a laboratory.
