Sweat on hands may cause corrosion of protective agents on brass objects such as taps and door knobs, new research suggests.

Researchers at the University of Leicester have discovered that the effectiveness of bacteria protection on brass objects in public places, such as schools and hospitals, can be compromised after sweaty hands have come into contact with them.

Brass objects such as those that contain copper, have an antimicrobial effect on bacteria,  used to protect the general public from the spread of disease. Yet human sweat can corrode these objects even within one hour after coming into contact with them. This has an adverse effect on the ability of antimicrobial protective layers on brass items to effectively kill bacteria. This is of particular concern in hospitals, where germs may easily spread through touching.

Copper has long been known to have an antimicrobial effect, which occurs as a result of an exchange between bacteria and copper that can lead to deterioration of bacteria DNA. However, salt in sweat can corrode this metal, thereby developing an oxide layer which starts the corrosion process.

Dr. John Bond OBE from the University of Leicester’s Department of Chemistry says that public places need to be kept free of brass corrosion through regular cleaning.

“While more research is needed in the study of sweat and brass corrosion, anywhere that needs to prevent the spread of bacteria, such as public buildings, schools and hospitals should be looking at using copper alloy on everyday items to help in avoiding the spread of disease,” said Dr. Bond in a statement.

The findings of the study are published in the journal Applied Surface Science.