Since the late 1950s, the Use Dilution Method (UD) has been the standard method to evaluate the efficacy of liquid disinfectants on hard surfaces. And for at least fifty years, it hasn’t changed much.
In the mid-2000s, the EPA led several efforts to update and clarify the method. A couple of key additions were made to better describe how to perform carrier quantitations, as well as establishing minimum carrier levels of greater than 10E6 organisms per carrier as an acceptable challenge. More recently, EPA has led discussions with AOAC and the industry that were focused on the establishment of an acceptable carrier count range between 10E6 and 10E7 for Staphylococcus aureus and Pseudomonas aeruginosa. With this proposed modification, procedures for standardizing inocula by dilution may be considered. In mid-November of this year, EPA’s BEAD (Biological and Economic Analysis Division) Lab will be hosting a laboratory workshop on the step-by-step conduct of the UD, as well as presenting recommendations for final modifications of the UD method and performance standards. ATS Labs will be there.
While ultimately both regulatory agencies and industry partners hope to move to a standardized quantitative disinfectant method, it is clear that the UD will continue to be an important tool for new product development, new disinfectant registrations, and EPA’s ongoing compliance testing for quite some time. And you can count on ATS Labs to be on the frontline, participating in current method improvements and new method collaborative studies to assure we have the know-how to test your products with the most appropriate methods available.
For more information or additional updates on the UD method, please contact ATS Labs.