Methods and articles for testing disinfectant and sanitizer efficacy

A method of evaluating the antimicrobial efficacy of a hard surface disinfectant or sanitizer, the method comprising:

• removing a primary container from a secondary container, at least one of the primary container or the secondary container being impermeable to moisture and oxygen, the primary container containing a preserved antimicrobial test article, the preserved antimicrobial test article comprising:
• a non-water soluble substrate, and
• a microbial layer attached to the substrate and comprising viable microbial material and a stabilizing mixture,
• wherein the viable microbial material comprises between 3.0 logs to 9.0 logs of viable microbial material
• and has a loss of viability of less than 1 log over at least 30 days at 4° C.;
• contacting the preserved antimicrobial test article with a predetermined amount of a test substance to evaluate an antimicrobial efficacy of a hard surface disinfectant or sanitizer without rehydrating the preserved antimicrobial test article and without detaching the microbial layer from the substrate prior to contact with the test substance;
• maintaining contact between the preserved antimicrobial test article and the test substance for a predetermined test contact time;
• contacting the preserved antimicrobial test article and the test substance with a neutralizer after the predetermined test contact time;
• agitating the preserved antimicrobial test article;
• and
• observing an indication of antimicrobial efficacy.