I'm guessing there is a very slight hint of onion powder in the baby food. It does surprise me that it's even in there in first place.

You can also try a can of stinky wet food (fish flavor).

I actually just used cooked rice and mixed it with a small amount of wet food and fed it to Skinny. His appetite came back within 2 days. Now he looks at me like "arent you hand feeding me anymore mom" LOL