Embodiments are directed towards methods and systems of depositing a uniform test-pathogen mixture onto a test article for testing the sterilization efficacy of an electromagnetic radiation or other sterilization process. The system includes a holding mechanism configured to removably secure the test article to the system. The system also includes a test-pathogen dispenser configured to uniformly deposit the test-pathogen mixture onto a reference surface of the test article. The system is structured so that at least one of the test article and the test-pathogen dispenser moves relative to the other. A plurality of test-pathogen mixture droplets or lines is deposited onto the reference surface in a predetermined test-pathogen pattern, such as, for example, a plurality of rows and columns of droplets. A distance from a dispenser tip of the test-pathogen dispenser to the reference surface of the test article may be determined to help maintain consistency between test-pathogen mixture droplets or lines.
