Residual Efficacy Testing for EPA Claims

Posted On: Oct 09, 2022

The Covid-19 pandemic changed many of the ways we understood public and personal safety, particularly the concept of antimicrobial efficacy, with a renewed focus on non-traditional surfaces. Prior to the pandemic, much of the approach to antimicrobial properties was generic and binary; Does a product demonstrate antimicrobial activity at the point of use? However, the pandemic thrust the public’s interest and understanding of antimicrobial efficacy forward, to the point where this non-specific approach was no longer valuable for the market’s needs. Manufacturers began including strain specific label claims, such as “Kills the Covid-19 Virus” on product labelling. Increased antimicrobial claims in non-traditional product categories, such as antiviral efficacy claims on treated fabrics for consumer wear or residual efficacy of disinfectants beyond the point of use, were becoming more popular. This increased demand for more in-depth labelling and marketing claims placed pressure on agencies such as the EPA to provide simplified regulatory pathways to make such claims. In response, the EPA began clarifying and establishing these pathways to simplify the testing, registration, and marketing of antimicrobial products. This action began with the clarification of regulatory testing requirements for Covid-19 specific label claims and has now advanced into the most recent development: regulatory guidance for residual efficacy claims on antimicrobial products.

In October of 2020, the EPA issued interim guidance on adding residual efficacy claims to antimicrobial products. Two years later, following public comments and input from EPA laboratory studies, the EPA implemented this interim guidance and plans to update the Series 810 Product Performance Test Guidelines to reflect this guidance. You can find the updated guidance document on the regulations.gov website using the reference EPA-HQ-OPP-2020-0529.

To summarize this guidance, residual efficacy products fall into two overarching categories, 1) Traditional disinfectants that also demonstrate residual properties and 2) Supplemental antimicrobial products (such as surface coatings, paints, treatments, etc.) that do not fit into the traditional disinfectant category established by the EPA. For disinfectants making claims against bacteria, a 5-log reduction is required. For all other claims, e.g., viral claims, coatings, films, solids, and paints, the general efficacy requirement is a 3-log reduction of microbial activity. Additionally, the type of product will determine the length of time pertinent to the residual claim. For example, a disinfectant product is required to demonstrate efficacy at a duration of 24 hours, while fixed solids and paints will need to determine residual efficacy by a factor of years. Finally, the product must also be subject to a durability assessment, tested through either and abrasion or chemical challenge depending on the product category.

It is important to note that this guidance is specifically for antimicrobial products for use on hard surfaces that already have data supporting a base non-residual disinfectant claim following the OCSPP 810.2200 Product Performance Test Guideline. Disinfectants for use in a health care setting or for human use may fall subject to additional regulatory requirements. Additionally, the guidance does not address residual claims for food contact surface or textile products. For additional clarification on these products, it is recommended that you contact the EPA directly.

Nelson Labs offers all the above-mentioned efficacy testing (including Covid-19, residual, and human use claims) at our Bozeman, MT facility. Nelson Labs Bozeman hosts over 30 years of EPA and antimicrobial testing experience and can help you navigate the testing and regulatory requirements to implement these additional claims into your products go-to-market strategy. Test scheduling is available now.

The increase in guidance by the EPA creates an exciting landscape, in which products can communicate their unique advantages in a level of detail not previously seen. This step forward in the antimicrobial industry not only offer competitive advantages to the manufacturers of these products, but also adds to the public safety tool box, which better prepares us to face the health care challenges (pandemic or otherwise) that may lie ahead.