Test methods for sterile medical device package — Part 10: Test for microbial barrier ranking of porous package material
1 Scope
The test method specified in this part of YY/T 0681 is used to determine the penetrability of airborne bacteria to porous materials for sterile medical device package. This test method is designed to test materials under the condition that bacterial spores can penetrate through the test materials, so as to rank the materials.
In this test method, it is required to operate microorganisms, only by trained personnel.
Note: See Annex B for the precision and bias of this test method.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 10739 Paper, board and pulps — Standard atmosphere for conditioning and testing
3 Term and definition
For the purposes of this document, the following term and definition apply.
3.1
porous package material
material used in medical package to provide an environmental and biological barrier while allowing sufficient airflow in gas sterilization (e.g., ethylene oxide, steam, gas plasma)
4 Summary of test method
4.1 Summary
The porous material samples are subjected to the challenge of Bacillus subtilis var. niger aerosol in the exposure chamber. Collect spores passing the porous sample with a filter membrane and count them. Log reduction value (LRV) is calculated using the difference between the logarithmic value of challenging spore number and the logarithmic value of porous-material-penetrating spore number.
4.2 Setting of standard conditions
This test method specifies the setting of standard conditions. By setting standard conditions, the material evaluations between laboratories are comparable. There are many factors for determining the standard conditions described in this test method. First of all, it is difficult to maintain spore aerosol for a long time (if the spore challenge time is too long, the test cost will also be increased). Secondly, in order to determine the differences between materials, it is necessary to conduct tests under the conditions that bacterial spores can pass the material. If a material is not passed by any spores, it may be expressed that it has stricter barrier performance than the challenging conditions. Thirdly, in order to make all the porous materials commercially available be able to detect spore penetration, a large spore challenge level is needed. The standard conditions described in this method are set based on these factors. However, because there are many factors affecting the determination of porous materials (see Clause 5), users may improve these conditions (i.e., bacteria challenge time and flow) after conducting research under standard conditions. The standard test parameters set in this test are as follows:
Foreword i
Introduction iii
1 Scope
2 Normative references
3 Term and definition
4 Summary of test method
5 Significance and use
6 Facilities and apparatus
7 Materials
8 Sample preparation
9 Apparatus preparation
10 Apparatus validation
11 Microbial procedures for test samples
12 Calculation of log reduction value (LRV)
13 Report
Annex A (Informative) Calculation example of LRV and the relation between LRV and spore retention rate
Annex B (Informative) Precision and bias
Bibliography
