Presumably this is a homework question. If so, can you tell us the context- what sort of decay have you studied, what subject (chemistry, biology, nuclear physics), level (year 9, GCSE, A level?) , what answer is needed (one sentence or 2000 words)
Good answer No,Knowledge!
It perfectly illustrates the point that it seems pointless posting a question when the questioner doesn't explain/know what they are really asking.
I seem to remember that when a body "decays" it can either be as a result of putrefaction (bacterial) or autolysis (enzymes, acids etc) or both, so even in the absence of bacteria, decay would occur.
(funny the things you remember!!)