Abstract
This study aimed to clarify the actual status of microbial contamination on shared keyboard instruments, particularly piano keys, and to propose hygienic usage methods. ATP swab tests and bacterial analyses were conducted on the keys of shared pianos installed in university music facilities to evaluate their contamination levels. In the ATP swab tests, high ATP values were detected at both ends of the keyboard (low and high registers), while the central playing area showed relatively lower values. However, a separate investigation of the mid-range keys of six pianos conducted in summer revealed generally high ATP values, indicating significant contamination. Bacterial analysis results showed that a large number of general bacteria were detected from all keys, with most appearing to be Staphylococcus spp, suggesting their origin from human hands. Furthermore, Staphylococcus aureus was detected from two piano keyboards, implying a potential risk to health. The disinfection efficacy verification revealed that even dry wiping with non-woven fabric reduced bacterial counts by approximately one-tenth. Commercial keyboard cleaners, regardless of whether they contained disinfectants, demonstrated high disinfection efficacy, reducing bacterial counts by two orders of magnitude. These results indicate that shared piano keys pose a potential risk of microbial transmission. Therefore, the importance of using cleaners appropriate for the key material, diligent post-use cleaning, thorough hand hygiene, and continuous awareness-raising among users to improve hygiene consciousness is suggested for the hygienic use of shared instruments and the reduction of infection risks.
