AOAC INTERNATIONAL, under contract with the U.S. Environmental Protection Agency (EPA), is working to develop a standardized, validated approach for evaluating efficacy of antimicrobial wipes (towelettes). To address issues and build consensus on method standardization and options/strategies for testing towelettes, representatives from government, contract laboratories, and industry shared technical information on laboratory-scale efficacy test methods for disinfectant towelettes and refined objectives for a proposed technical workshop. The goal is to standardize towelette testing practices to give consumers, producers, and regulators confidence in analytical results and product efficacy.

The use of towelettes is becoming increasingly popular in consumer (household and personal) and industrial (manufacturing and health care) markets, with new product innovations and expanding applications. But it is these innovations and applications that lead to challenges in evaluating the efficacy of wipes. Today, towelettes come in a variety of products, comprised of different matrixes (i.e., what the towelette is made of), saturation, size, and packaging. Further adding to the challenge is that these products state a variety of claims (contact time, application, maintenance of wetness, reapplication of product, and preclean).

In testing methodology, roundtable participants recommended that issues such as the following be addressed: wetness; wiping (number of passes, direction, pressure); folding (size, number of folds); size; position of towelette in container; surface area and type; carrier counts; soil load; neutralization confirmation; expressed liquid testing; carriers per towelette; analysis of used towelette; formulation; extraction procedure from towelette; and non-active control.

During the roundtable, participants examined various testing strategies for evaluating the efficacy of antimicrobial wipes. These strategies included surface wetness tests, a liquid-only option which requires extracting liquid from towelettes and testing quantitatively, a towelette-only option, and a tiered approach which requires extracting the liquid and testing both the liquid and towelette.

Armed with valuable input provided by stakeholders at the roundtable, next steps include further discussion by the Method Committee on Antimicrobial Efficacy Testing on the best approach for testing disinfectant towelettes, preliminary testing and data collection on new methodology, quantitative data collection on current methodology, comparative testing between equivalent liquid and towelette products as recommended, and determination of wetness parameters.

In addition, a technical workshop is proposed for early 2010 to move the effort forward. Initial plans for the proposed workshop include laboratory-based discussions, laboratory demonstrations of current and alternative methodology, and problem solving onsite.

Full coverage of the Roundtable on Towelettes is published in the November/December issue of Inside Laboratory Management. For more information, contact Olayinka Ladeji, AOAC consultant, at oladeji@aoac.org or Maria Nelson, AOAC technical consultant, at mnelson@aoac.org.

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