Conducting contact plate tests in practice

Standardized procedures are recommended for meaningful results: Hands should be in their “everyday state,” not pre-washed or disinfected, before testing. The agar plate is gently pressed onto the skin for a few seconds, then sealed and labeled. Plates are incubated for 2–3 days at 30–35 °C for bacterial growth and for 5–7 days at 20–25 °C to detect yeasts and molds. Colonies can then be counted and classified.

Contact plate tests are suitable for various environments: from hospitals and hotel kitchens to food production facilities. Results are influenced by the timing of sampling (e.g., before or after a shift), frequency of checks, and personnel training in hygiene. Used in training or internal audits, contact plate tests help raise staff awareness of consistent hand hygiene practices.