Developers, manufacturers and marketers of residual products that provide bactericidal efficacy for days, weeks or months must meet the criteria detailed with EPA guidance for making bactericidal claims. Element’s antimicrobial testing experts offer comprehensive residual bacterial efficacy testing services and can help you meet regulatory expectations and requirements for residual product registration.

Residual products may be in the form of a coating on a surface or imbedded into a surface. These products can provide additional disinfection or sanitization between regular disinfection or cleaning cycles. Residual products are desired in areas like public transportation where the surfaces are touched many times between cleaning and disinfection cycles. The US EPA recently released guidance for bactericidal efficacy testing and criteria for making bactericidal claims for residual products. Generate data to support bactericidal claims that meets the EPA’s requirements with Element’s antimicrobial residual efficacy testing services.

Residual bactericidal efficacy test methods

Element’s antimicrobial experts test residual products for bactericidal efficacy to a wide range of established methodology:

Residual Self-Sanitizing Efficacy Screen - The purpose of this study is to determine basic self-sanitizing activity of antimicrobial products applied to hard, nonporous, inanimate, non-food contact surfaces following exposure. This method applies to products intended for use on inanimate, nonporous, non-food contact hard surfaces for the evaluation of residual antimicrobial efficacy. These products may be sprayed or applied by other means as specified by the Sponsor.

EPA Residual Self-Sanitizing Activity of Dried Chemical Residues on Hard, Non-Porous Surfaces (with exposure and wear activity) - In this method, a series of glass or stainless-steel surfaces are treated with the product and the product is allowed to dry over the surfaces. The treated surfaces then undergo a series of physical wear procedures followed by systematic low-level inoculation of test organism to simulate routine use and contamination of the surface. After completion of the wear cycles, the treated surfaces are inoculated with the test organism to evaluate the residual sanitizing efficacy of the surface and the survivors are quantitatively assayed. The resulting plates are incubated, enumerated and a percent and log10 reduction is determined as compared to a population control.

In order to successfully demonstrate residual self-sanitizing efficacy, the product must demonstrate a 99.9% reduction after 24 hours following application. Typical test organisms include Staphylococcus aureus and Klebsiella aerogenes or Klebsiella pneumoniae. Additional pathogens of clinical, occupational or household relevance are often tested as well.

Test Method for Determining the Efficacy of Antimicrobial Surface Coatings - The purpose of this study is to provide data to support the registration of coatings applied to surfaces that are intended to provide residual long lasting antimicrobial activity for a period of weeks and are designed to be supplements to standard disinfection practices.

A film of organism cells applied on the antimicrobial surface (which has undergone chemical exposures and physical abrasions) will be exposed for a specified exposure time (≤2 hours). After exposure, the carriers will be neutralized and assayed for survivors. Appropriate culture purity, sterility, population and neutralization confirmation controls are performed.

Test Method for the Evaluation of Bactericidal Activity of Hard, Non-porous Copper-Containing Surface Products - The purpose of this study is to provide data to support the registration of copper-containing surface products that are intended to provide residual long lasting antimicrobial activity for a period of weeks and are designed to be supplements to standard disinfection practices.

A film of organism cells applied on the antimicrobial surface (which has undergone chemical exposures and physical abrasions) will be exposed for a specified exposure time (≤2 hours). After exposure, the carriers will be neutralized and assayed for survivors. Appropriate culture purity, sterility, population and neutralization confirmation controls are performed.

Residual Efficacy Using an Ex-Vivo Skin Model - This test method is used to evaluate the residual activity of topical skin products against single selected microorganisms using an ex-vivo skin model. A film of cells is placed onto treated substrate carriers designed to mimic skin. After exposure, the carriers are neutralized and assayed for survivors. Appropriate culture purity, sterility, population and neutralization confirmation controls are performed.

Residual Self-Sanitizing Activity of Laundry Additives - The purpose of this test method is to quantitatively determine the residual self-sanitizing activity of a laundry additive. Regulatory agencies require that antimicrobial products which bear claims to provide residual self-sanitizing activity (i.e., reduction in the number of microorganisms which may contaminate the items) on treated fabrics typically used in the final rinse of automatic washing machines be supported by appropriate data. For residual products intended for use on fabrics, a fabric carrier method is used in the generation of the supporting data.

Treated fabric is prepared using a simulated laundry process or is provided for use by the Sponsor. Fabric carrier swatches are inoculated with a suspension of the test organism and exposed for a specified exposure time. Following the Sponsor exposure, the carriers are neutralized and assayed for survivors. Appropriate culture purity, sterility, neutralization confirmation, initial suspension and population controls are performed.

The Element advantage

Element has been the leader in antimicrobial testing for more than three decades. Our consultative antimicrobial and regulatory experts stay up to date on market trends and regulatory guidance, providing unparalleled support and testing services. Confidently and successfully navigate residual product registration with the support of Element.

For more information about Element’s EPA antimicrobial efficacy testing and antimicrobial residual efficacy testing services, contact us today.

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