Composting Lootables/Recipes/Functions?

I'm looking to add poisonous potatoes into the selection of things that can be composted.
I'm a little confused as to how I would even begin to do this, there seems to be little information regarding the composter, I'm not sure if it's done via lootables, recipes, or functions?
I've had a look at the "More Compostable Items" datapack and it seems to be using functions? I've not really looked into those as of yet and I'm trying to see if there's a way to do this without needing to use functions?
Thanks in advance,
~Blood