Criteria for laboratory accreditation conducting microbiological tests according to NC-ISO / IEC 17025: 00

Abstract

In the last years, the search of indicators of the grade of microbial
contamination of a sample of water is one of the aspects in which more emphasis
has been made in the laboratories of analysis of waters and wastewaters. It is of
vital importance in the environmental microbiology to have a control of the quality,
inside which should be considered the analytical method, so a good quality of
the resulting data is guaranteed. The quantitative determination of the coliforms
presence offers a rational index of the bacterial content of the water. This work,
had as objective to specify the approaches for the accreditation of laboratories
that carry out microbiological analysis according to NC-ISO/IEC 17025:00, referred
to the microbiological rehearsals of total and fecal coliforms in waters and
wastewaters by means of the technique of Multiple Tubes of Fermentation. This
standard constitutes the technical-methodological basis for the accreditation of
these rehearsals. For the evaluation of these laboratories with a view to their
accreditation, the factors that can influence on the results was analyzed. It is
specify the factors of more incidence to keep in mind for the accreditation are:
the local and environmental conditions, the culture media and reagents, the validation
of the method and verification of the results, the insurance of the quality
of the results and control of the quality, the manipulation and identification of
samples and estimatimation of the uncertainty, that constitutes an objective and
indispensable basis in the process of evaluation of the conformity of a service for
the requirements a consumers demands.