my beagles food allergies

Question
Is it possible that my lemon beagle could be allergic to the sweet potato in her food? I switched her from the Eukenuba Salmon and Rice to Taste of the Wild Salmon and Sweet Potato and she's been licking again and has an ear infection which she didn't have for about 6mo on the Salmon and Rice, but I heard that Taste of the Wild was even better than the Eukenuba so I switched her although I think she was doing better on the first one.

Answer
Absolutely possible....... you might want to look at Anova or go back to the old one. Just remember when you switch foods to take about a week to do that and mix the two together half and half at first and then slowly decrease the other one until its not in the mix. Otherwise she can get an upset stomach and/or diarrhea.