In Laws

I love my in laws to pieces but I just want some advice. Last night we went out for dinner and my FIL had our 5mth old on his lap while we were eating ice cream. He grabbed her dummy and was wiping it in the sorbet and giving it to her. After getting caught out by my MIL, my hubby jumped in and said it was fine so he kept doing it. I have a huge problem with it because a) the sugar content and b) the introduction to egg (our child health nurse said to be cautious of this because she has a cows milk allergy).

Am I overreacting? And how do I approach the topic now? They look after her often and I don't want them to give her food freely yet, particularly things that have processed sugar!