すみません、このたこ焼きに、エビは入っていますか？ — Excuse me, does this takoyaki contain shrimp? (Festival · Food · Allergen, Formal — to staff, JLPT N4)

Gesture & etiquette

Point to the food item, then perhaps make a motion like checking (but not touching).

Street food vendors might not always know every ingredient, especially with pre-mixed batters. For severe allergies, caution is advised. Have a list of your specific allergens in Japanese.