ASTM G21 – Antifungal Fungal Resistance Test

ASTM G21 is a standard antifungal product test for determining the fungal resistance of plastics and polymeric materials.

Synthetic polymers are generally resistant to fungi, but the additives  (such as colorants, stabilizers, and plasticizers) used in the polymer may not be. These additives may contribute to the fungal growth and unsightly conditions.

Products made of plastics and foam are commonly tested with ASTM G21, but the method can also be used for a wide range of other materials and products.

ASTM G21 is useful for interior products including vinyl, foam, gaskets, and rubber and is often used for materials in plumbing, baths, and bedding.  ASTM G21 is also used for outdoor products such as siding, shingles, pool covers, marine plastics, fishing and boating gear, footwear, sporting goods and polymeric coatings.

ASTM G21 consists of exposing plastics and other materials to a fungal inoculum over 28 days of testing.  A mixed fungal inoculum is standard, but individual fungi can be requested as an alternative.

The ASTM G21 test method challenges materials with a wide variety of fungal species, ranging from common environmental fungi to agricultural pathogens and even antibacterial compound producing fungi, all of which have different growth requirements and enzymatic properties.

As a product test laboratory, Situ Biosciences offers a range of antifungal and antibacterial tests for quality control testing, antimicrobial performance, and product development.

Moreover, Situ Biosciences is excited to announce that we have produced the world’s first Certified Reference Materials for validating antimicrobial laboratory testing!

Our ISO 17034 Certified Test Controls are available for standard antimicrobial tests, including the ASTM G21 method. Click here to learn more about the ASTM G21 Certified Reference Material and visit our shop today.

For more information about ASTM G21 testing, antimicrobial testing, and other test options for anti-fungal products, contact our antimicrobial lab at 847-483-9950 or