Key Takeaways
- JIS Z 2801 is a quantitative antibacterial test designed for plastics and other non-porous surfaces.
- It determines log reduction in bacterial population after a defined incubation period.
- ASTM G22 assesses resistance to bacterial growth on polymeric materials.
- ASTM G22 involves incubating samples for up to ~21 days, after which plates are examined for bacterial growth or inhibition.
- In JIS Z 2801 testing, incubation period is 24 hours and results are expressed as log reduction
- JIS Z 2801 supports antibacterial performance claims, while ASTM G22 is primarily used for growth resistance screening.
Summary
JIS Z 2801 and ASTM G22 are widely recognized standards for evaluating antimicrobial performance in plastics, but they serve different purposes. JIS Z 2801 provides quantitative antibacterial efficacy, making it ideal for regulatory claims and validation. In contrast, ASTM G22 is a qualitative method that assesses whether bacteria can grow on a material, making it better suited for early-stage screening. Selecting the right test depends on whether you need measurable antibacterial performance or a simple indication of microbial resistance.
Why does this comparison matter?
Understanding the difference between the two standards is critical for multiple aspects of product development and market success.
From a regulatory perspective, selecting the wrong test method can lead to unsupported or invalid claims, potentially causing compliance issues. In terms of product validating, the right test ensures that materials truly meet their intended antimicrobial performance, rather than just appearing effective under limited conditions.
Additionally, distinguishing between durability and efficacy is essential, while one standard may demonstrate the ability to kill bacteria, the other may only indicate resistance to bacterial growth. This distinction directly impacts how a product performs in real-world applications and how its benefits are communicated to consumers.
What is JIS Z 2801?
JIS Z 2801 is a quantitative antibacterial test method used to measure bacterial reduction on plastics and non-porous surfaces under controlled laboratory conditions. By validating antibacterial efficacy, it supports marketing and regulatory claims.
JIS Z 2801 measures:
- Reduction in viable bacteria
- Expressed as log reduction value
Methodology:
The test plastic or non-porous surface is inoculated with bacteria and covered for the specified incubation period. Post incubation, surviving bacteria are recovered and counted.
Passing criteria:
To pass JIS Z2801 test, the product typically requires to achieve higher log reduction compared to the control.
What is ASTM G22?
ASTM G22 is a qualitative test method developed by ASTM international to evaluate the resistance of plastics to bacterial growth under favourable conditions.
It measures:
Presence or absence of bacterial growth
Methodology:
The test samples are exposed to bacterial cultures and incubated under favourable conditions for growth. Later, the growth is monitored over 21-28 days.
Passing criteria:
The results are qualitative. If there is any growth observed, it indicates poor resistance whereas no growth indicates good resistance.
JIS Z 2801 vs ASTM G22 : Key differences
Mandatory test strains
JIS Z 2801 โ Staphylococcus aureus and Escherichia coli are the bacterial strains recommended by this test method.
ASTM G22 โ Uses a single bacterial strain, Pseudomonas aeruginosa, to validate the antimicrobial resistance of plastics.
Scope of Products
JIS Z 2801 โ Broadly used for a variety of nonporous materials and is not limited to plastics.
ASTM G22 โ Focused specifically on synthetic polymeric materials and their vulnerability to bacterial degradation.
Origin of Standard
JIS Z 2801 โ Initially this test was developed by Japanese Industrial Standards and it is popular across Asia and recognized globally.
ASTM G22 โ Developed by ASTM International, it is widely used in the United States and internationally.
| Parameter | JIS Z 2801 | ASTM G22 |
| Origin | Japanese Industrial Standard | ASTM international |
| Purpose | Quantitative determination of antibacterial activity on treated surfaces under controlled | Qualitative assessment of a materialโs susceptibility to bacterial growth under favourable environmental conditions |
| Application | Final product validation, regulatory submissions and antibacterial claims | Early stage screening and material performance |
| Results | Quantitative results expressed as log reduction | Qualitative results expressed as visual growth |
When to use JIS Z 2801
- When there is need to make antibacterial performance claims
- When quantitative data is required for regulatory submissions
- When demonstrating rapid antibacterial efficacy under defined conditions
When to use ASTM G22
- To assess if a material supports or resists bacterial growth
- For durability or material screening studies
- To understand long-term behaviour on surfaces
- In early-stage product development
Can you use both tests together?
Use both only when your objective requires two different insights.
- If your goal is antibacterial claims, then JIS Z 2801 alone is sufficient
- If your goal is material susceptibility or durability against bacterial attack, ASTM G22 alone is enough
- If your goal is comprehensive understanding (antibacterial performance and durability) you can use both standards.
Common mistakes to avoid
Avoiding common mistakes in antimicrobial testing is essential to ensure accurate results and credible claims.
- Using ASTM G22 for product claims, even though it does not provide quantitative proof of antibacterial efficacy
- Assuming that qualitative results are equivalent to quantitative outcomes, โno growthโ in ASTM G22 does not necessarily mean that bacteria are actively killed.
- Skipping validation testing is a critical error, as relying solely on screening methods is insufficient for regulatory compliance or marketing purposes.
Why choose MIS
At MIS, antimicrobial testing is designed to align with both scientific rigor and regulatory expectations. We test for both, ASTM G22 and JIS Z 2801, generating data that not only accurate but is also aligned with global standards. With expertise in international testing methods, our microbiology team provides end-to-end support from early stage R&D screening to final validation.
FAQs
Is ASTM G22 an antibacterial test?
ASTM G22 is not a true antibacterial efficacy test, it is a qualitative method that evaluates whether bacteria can grow on a material. It assesses resistance to bacterial colonization rather than the ability to actively kill bacteria.
Can ASTM G22 replace JIS Z 2801?
No, ASTM G22 cannot replace JIS Z 2801 because it does not provide quantitative data on bacterial reduction. JIS Z 2801 is required when measurable antibacterial efficacy and claim support are needed.
Does JIS Z 2801 test fungi?
No, JIS Z 2801 is specifically designed to evaluate antibacterial activity against bacteria. Separate standards are required to assess antifungal or mold resistance.
When should both be used together?
Both JIS Z 2801 and ASTM G22 should be used together when you need to evaluate both antibacterial performance and material durability against bacterial attack.
