The dilution method is used to obtain an indirect count of microorganisms, e.g. fecal bacteria commonly used as human contamination indicators, in a suspension.
The Most Probable Number estimate provides a quantification of dilution method results.
This estimate is commonly obtained by using Poisson distribution.
Although the use of binomial distribution leads to lower estimates, only a 5% maximum difference was noted, which is negligible in terms of MPN precision.
Relative MPN bias is considerable (35% on average) and apparently varies with true bacterial density; however the binomial model reduces its magnitude by 5-8%. A new method for determining Bayesian intervals based on an equilikelihood criterion is presented.
Mots-clés Pascal : Qualité eau, Coliforme, Feces, Pollution eau, Indicateur biologique, Limite confiance, Loi Poisson, Nombre le plus probable
Mots-clés Pascal anglais : Water quality, Coliforms, Feces, Water pollution, Biological indicator, Confidence limit, Poisson distribution
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 93-0397572
Code Inist : 001D16A02. Création : 199406.