Hi Mary
we use a chemical called byotrol, which is a microbial biocide, it is certified to kill MRSA, E-COLI,C-DIFF, LEGIONELLA, LISTERIA etc,etc.
we use it if we ever needto sterilise/sanitise a pub cellar after an eviction, as landlords tend to do nasty things when they know they are going to be kicked out.
it keeps working on all surfaces for upto 7 days,it has also been tested as safe by the environment agency, I will email you some details.
regards