Hello Ellen,

Sure, meat tenderizer or similar proteolytic compounds will break down
proteins - but nowhere NEAR as fast as bleach!  Put a gram of tissue in 50
ml of Adolph's and a gram of tissue in 50 ml of Chlorox.  After a hour the
tissue in Adolph's may be tender, but the tissue in Chlorox will be GONE!
Therefore I wouldn't worry about the effect of the tenderizer on the protein
matrix of the shell - which incidentally is far less than one percent of the
shell's total mass.  Putting shells in bleach or in alcohol will have
essentially opposite effects.  Both solutions, as you said, will kill the
bacteria and stop putrefaction.  But alcohol will preserve any remaining
tissue (as well as the bacteria), guaranteeing that no further breakdown
occurs, while bleach will rapidly dissolve any remaining tissue (as well as
the bacteria), far more rapidly than the bacteria could.  The addition of
liquid dish detergent should do no harm.  I don't know if it would do any
good.  If it helps, let us know.

Paul M.