Likely does not have anything to do with the food.
My Max has had episodes of reverse sneezing from getting an allergen up his nose. Some people blow into the nose, and some people cover the nose for a few seconds, which makes the dog swallow and usually ends the episode.
Very gently stroking the neck can also help, as you did. Usually calming the dog down so that he/she swallows does this trick.
Here is a thread in the YT library for you:
http://www.yorkietalk.com/forums/die...d-trachea.html