Beef heart is good, nutricient and parasite free, pork heart is another good choice but just need to slice it as they might not digest well with larger pieces..
I just have the butcher trim all the fat stuffs (white) out, then double grind it.
When I get it home,
I freeze it in sandwich bags as flat as I can get it. (like 1/4" thick)
Then I just shave off long 1" long pieces and feed.
I fed my Aro this everyday along with prawns, pellets, SW's...
If you trim the beef heart of all the fat ...and properly feed the ammount the aro will eat at one meal, there is no extra mess to have to deal with...