It depends on how you define specialty. I mean, it's not as simple as apples, corn, wheat, even bread. it requires cows milk to be processed to be more digestible, then added oils, minerals, etc. Some use soy, some are hydrolyzed proteins, then can be ready to go, concentrated, or powdered. So, there is some significant processing that goes into baby formula. That's what I meant by specialty. it's more manufactured than harvested. Just like wet cat food isn't all that special, but it comes in Aluminum cans, and that was in short supply for a month or so. Baby formula is more complicated than milk.
20% is substantial, but as I said, we also export a much more significant portion of our food supply. We do so, because some things are cheaper for us to import. However, we are one of a handful of countries that are considered to have food stability. meaning, we don't need food from outside countries to survive. We can make enough on our own. Russia, Canada, I think Mexico, and a few others are similar. As I and others have said, we use a lot of corn towards ethanol, we'd just stop that. There is plenty of food here.
And I did say we'd see price increases. Just not overall food shortages. Again, where is the OP going with this? Global food issues, or US food shortages? Is the expectation that we should all raise our own chickens and have urban farms? Should be go full "prepper" and have a 500 gallon tank of water in the garage, and a 50 day supply of MRE's?