Microbial Ingress Testing with Bioaerosols

Standard Microbial Ingress Testing is required for interpatient medical devices and/or devices that have contact with a patient’s bloodstream.

Such devices include intravenous and urinary catheters, IV tubing and connecting devices, drug delivery systems, endoscopes, and implantable medical devices. These tests simulate a worst-case exposure to critical parts of the devices such as buttons, seams, and ports.

Ordinary microbial ingress tests rely on ordinary liquid microbial inocula, but for some products and applications, challenging with bioaerosols makes more sense.

Bioaerosols have some advantages over liquid inocula for ingress studies: They are tiny, often less than half a micron in diameter, they’re representative of airborne contamination in manufacturing and clinical settings, and the airborne microorganisms settle upon objects in the same fashion dust and other contaminants settle on them in ordinary use.

One example of microbial ingress testing using bioaerosols can be found in ASTM E3251-20, Standard Test Method for Microbial Ingress Testing on Single-Use Systems. This standard was designed to challenge critical fluid paths in a biopharmaceutical manufacturing environment. For this method, test devices are filled with sterile broth, then placed into an aerosol test chamber and exposed to aerosols for a validated period, such as one hour. Then devices are incubated and observed for growth within the sterile critical fluid channel.

If your company is interested in exploring bioaerosols as a way to challenge the integrity of a manufacturing component, medical device, or package, please contact our lab and we will be glad to discuss your project.