How VOCs Affect Antimicrobial Testing And How We Solve It at BioLabTests

Understanding VOCs and Their Impact on Antimicrobial Testing

Consumer products are frequently manufactured using polymeric materials such as silicone, polypropylene, and nylon. These materials are used in a wide range of applications including tableware, building materials, and clothing.

However, residual solvents, monomers, and additives are just a few of the harmful substances commonly found in these products and can be a source of volatile organic compounds (VOCs), chemicals often associated with unpleasant or “chemical” odours reported by consumers ^[1].

What are Volatile Organic Compounds (VOCs)?

VOCs are a class of chemicals that include substances such as formaldehyde, toluene, and benzene. Under normal environmental conditions, VOCs vaporise easily and release molecules into the air ^[2].

In polymeric materials, VOC emissions can happen during the product’s lifespan, particularly when exposed to heat and UV radiation. However, the structure, molecular weight, and crystallinity of the polymer all influence VOC release. For example, polymers with a lower molecular weight may emit more VOCs due to their higher volatility.

Additives like plasticisers, antioxidants, flame retardants, and colourants are used to enhance the durability, performance, or appearance of polymers but can be a significant source of VOCs. Some of these additives may react with environmental compounds like hydroxyl radicals to form new VOCs, further complicating emissions [3].

How do VOCs Interfere with Antibacterial Validation Tests?

Volatile organic compounds can disrupt the results of antimicrobial efficacy testing, particularly using methods such as ISO 22196. These emissions can interfere by:

• Inhibiting the growth of microorganisms, leading to false-positive results
• Exhibiting antimicrobial properties unrelated to the treated article
• Masking the actual performance of the test substance or material

For example, formaldehyde, a common VOC found in polymeric materials, has well-documented antimicrobial properties. It can damage bacterial DNA and proteins by forming cross-links^[4], which disrupts vital processes and leads to cell apoptosis (cell death).

Why Is Accelerated Ageing Important When VOCs Are Present?

Accelerated ageing is an important first step towards tackling the problem of VOC interference. This procedure helps to off-gas VOCs prior to testing by simulating the general exposure a product might encounter over time. It helps guarantee that antibacterial validation tests, like ISO 22196, measure just the action of the active antimicrobial agent and not background emissions from the material itself by eliminating or lowering interfering chemicals.

Interested in learning more or testing your products?

References

1. https://doi.org/10.3389/fpubh.2019.00202

2. https://doi.org/10.3390/ijerph182413147

3. https://doi.org/10.1016/j.heliyon.2020.e03314

4. https://doi.org/10.3390/microorganisms10020220