Microbiological tests of sterility of medical devices. EN ISO 11737-1: 2018, Part 1: Determination of the population of microorganisms in products.

Tests not accredited in our laboratory.

Tests with the Certificate of Good Laboratory Practices (GLPs).

The EN ISO 11737-1: 2018 standard, part 1, indicates the procedures to carry out the enumeration and microbiological characterization of the population of viable microorganisms on the outside or inside of a health product, component, raw material or container, following the ISO standard 11737-1: 2018. 

The term bioburden is used to describe the population of viable microorganisms present in the product. Knowledge of bioburden can be used in a variety of situations such as to: validate and revalidate sterilization processes; routinely monitor the control of manufacturing processes; monitor the raw material, its components or packaging; evaluate the effectiveness of cleaning processes; and/or for environmental control of work areas.

The biological load of a product is the sum of microorganisms from various sources, including the raw materials themselves, the manufacturing process of its components, the assembly process, the manufacturing environment, the agents that facilitate assembly/manufacturing (for example, compressed gases, water, lubricants), cleaning processes and the packaging of finished products. To control the bioburden, attention should be paid to the microbiological status of each of these potential sources. In this way, the biological load can be used for the control of raw materials, the acceptance of input components, evaluation of the process steps or the qualification of a sterilization process, to confirm the substantiation of a radiation sterilization dose, or an over-lethality sterilization cycle, among others. 

It should be noted that it is not possible to define a single method of extracting microorganisms present in medical devices. Depending on the characteristics of the products and the purpose to be achieved, the ISO 11737-1: 2018 standard specifies the requirements for the correct determination of the biological load of medical devices and the recommendations to carry out its quantification and identification, whether they are present on the outside, or inside, in their components, in the raw material with which they are made or in the container in which they are introduced.

In addition to the detection of the microorganisms in culture and their enumeration, the characterization of the microorganisms is required. The nature and extent of the characterization of the microorganisms that make up the bioburden depends on the intended use of this information. At IVAMI, the morphological characterization of the colonies, cell morphology and staining techniques, metabolic characterization through biochemical tests and genotypic analysis of the different isolated morphotypes can be carried out at the client´s request.

The results of the microbial load will be offered as the total CFU recovered from the test product after undergoing a microorganism extraction process. When a portion of the extract is used to determine bioburden and zero CFUs are recovered, results are typically reported as “less than X”, where “1/X” is representative of the extract tested.

The manufacturer must specify acceptable levels of bioburden on the outside or inside of a product or group of products based on historical data collection. Initially, if desired, temporary levels can be established that can be evaluated later according to the data collected.