From The Collaborative International Dictionary of English v.0.48 :
Putridness \Pu"trid*ness\, n.
Putridity. --Floyer.
[1913 Webster]
From WordNet (r) 3.0 (2006) :
putridness
n 1: in a state of progressive putrefaction [syn: putrescence,
putridness, rottenness, corruption]