“Contact time” is the amount of time a disinfectant must remain visibly wet on a surface to effectively kill a specific pathogen.
The time is usually highlighted on the product label and will usually vary anywhere from 30 seconds to 10 minutes depending on the type of pathogen that needs eliminating.
As far as we know, no disinfectant kills germs immediately upon contact and every germicidal chemical product should have a contact time associated with it if a specific germ kill claim is being made. Remember, if the surface isn’t staying wet for the length of the contact time recommended, then the surface is not being disinfected and germs will continue to breed. Spraying the surface with a disinfectant and then immediately wiping it with a cloth will serve no real benefit as the disinfectant was not allowed enough time to kill the germs before being wiped away.
Contact times are not suggestions, they form part of the manufacturer’s instructions for product effectiveness and have been scrupulously tested under laboratory conditions in order to pass any testing claim.