Irradiation Sterilization of Medical Devices (6) Bioburden Detection

Bioburden testing The effectiveness of irradiation sterilization depends on the amount and type of bioburden on the product. Therefore, the bioburden must be measured when determining the sterilization dose, periodically on a daily basis, and at dose audits. Once the development of bioburden or type of enterprise changes, it may lead to the failure of the sterilization dose audit and affect the effectiveness of the original sterilization dose that can be set. Therefore, in daily operation and management, it is necessary to control various social factors that may affect bioburden, such as materials, production and living environment, production process, product market structure, composition, etc. As these factors change, their impact on bioburden needs to be carefully assessed.

The main criteria for bioburden testing related to bioburden are as follows:

GB/T 19973.1-2015 ISO 11737-1: Microbiological Methods for Sterilization of Medical Devices 2006 Part 1: Determination of Total Microorganisms on Products

GB/T 19973.2-2018 idt ISO 11737-2:2009 Sterilization of medical service devices - Microbiological research methods - Part 1: Sterility testing for the definition, validation and maintenance of the sterilization process

Bioburden assay collection technique is another important factor affecting the results of bioburden assays. The first decision to use bioburden collection technology is the format of the product. For liquid or soluble medical devices or their components, membrane filtration can be used directly, but it may be necessary to consider whether there are fibers or particles remaining in the liquid or after dissolution. Effect of substances on filtration. However, for poorly soluble medical devices, regardless of the influence of SIP, bioburden measurement is only an estimate and accurate results are neither possible nor necessary.

1. The number of original microorganisms attached to medical devices is unknown. Gaps in assessments using vaccination methods can be very large. Therefore, it is almost impossible to evaluate whether a certain collection technology is suitable for a certain medical device product, and can only be selected based on factors such as product characteristics, experience, and ease of operation. The appendix of 19973.1 gives information collection techniques commonly used by some enterprises, such as bag peristalsis, ultrasonic elution, shaking, vortex mixing, rinsing, stirring and cutting (crushing), wiping, etc., and gives some methods that can be used Requirements and safety precautions are required.

2. Bioburden detection, when bioburden is collected, if the collection technique used leads to the death of microorganisms, or if the collection time is too long and results in the growth of microorganisms, the obtained bioburden may deviate from the actual value. Since enterprises cannot predict the original microorganisms attached to medical devices, it is not reliable to use the inoculation method to evaluate the recovery rate, and it is also difficult to evaluate the possibility of microbial death or growth caused by the development of information collection data technology. question. Of course, for some products, it may be possible to assess by inoculation. Therefore, in most cases, the collection method and eluent can be selected according to some instructions in 19973 and the Chinese Pharmacopoeia, combined with product characteristics, and the collection time should be minimized to avoid the growth of microorganisms. However, after choosing a collection technique and determining parameters, conditions can be compared by inoculation or by deliberately increasing bioburden. For example, evaluation of acquisition parameters such as shaking frequency, shaking time, sequence, etc.

The role of the correction factor is mainly in the selection of the method for determining the sterilization dose, and has little effect on the effectiveness of the sterilization dose. Of course, the correct and reasonable selection of research methods for the determination of sterilization dose is also an important factor affecting the effectiveness of sterilization dose. If the establishment method is not chosen correctly, it is difficult to say whether the effectiveness of the sterilization dose can be guaranteed.