Bacteria starts to party on the outside while the insulated interior remains frozen or very cold. Suit yourself, but this is also why you don't thaw a frozen turkey this way-
it's either done in cold water (faster) or in refrigerator (@ 40* takes days), so that it's never warm enough for bacteria to multiply. Just remember, cooking destroys lots
of bacteria too, & our snakes eat raw, & even worse, their food is intact (lots of bacteria in GI tract).