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Quality Assurance of Sterilized Products: Verification of a Model Relating Frequency of Contaminated Items and Increasing Radiation Dose
Author(s) -
KHAN A. A.,
TALLENTIRE A.,
DWYER J.
Publication year - 1977
Publication title -
journal of applied bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 0021-8847
DOI - 10.1111/j.1365-2672.1977.tb00744.x
Subject(s) - bacillus pumilus , contamination , serratia marcescens , quality assurance , statistics , population , radiation , mathematics , biological system , biology , physics , medicine , nuclear physics , ecology , bacteria , environmental health , pathology , biochemistry , genetics , external quality assessment , escherichia coli , gene
Values of the y ‐radiation resistance parameters ( k and n of the ‘multi‐hit’ expression) for Bacillus pumilus E601 spores and Serratia marcescens cells have been determined and the constancy of values for a given test condition demonstrated. These organisms, differing by a factor of about 50 in k value, have been included in a laboratory test system for use in verification of a model describing the dependence of the proportion of contaminated items in a population of items on radiation dose. The proportions of contaminated units of the test system at various y‐radiation doses have been measured for different initial numbers and types of organisms present in units either singly or together. Using the model, the probabilities of contaminated units for corresponding sets of conditions have been evaluated together with associated variances. Measured proportions and predicted probabilities agree well, showing that the model holds in a laboratory contrived situation.