I carried a bunch of food from the US to Argentina via Santiago. I had two separate itineraries so I was supposed to clear customs in Santiago and then recheck my bag. But I went to the lost bag office in the SCL airport with my bags--before clearing customs and with a little 'help' and a 'tip' I got them to clear the bag to go to Argentina without messing around with Chilean customs. You can do the same thing in Argentina if you get hassled- pesos solve lots of problems.
On the other hand why bother with all of this when you're about to eat a ton of other local stuff that you won't be sure what's in it? A few bars and things are the tip of the iceberg I'd think unless you plan to bring everything. The other option is to ship a big box of food ahead and pray that it makes it.