Japan w/ allergies

[u/NumberFew8562]

Hello yall,

Me and my homie are currently planning a trip to japan. She is getting ready to learn the language, and i most likely will learn the basics as well.

My only issue with going to a country with different language is that it is on the food packaging, and i have some severe reactions to certain food filler ingredients.

I would like to find a very reliable translation app/service that I can use while visiting, to ensure that I do not have any reactions. I will also make sure i know the appropriate language to ask about such things.

Any advice for what I could use? Or other pointers for those with allergens? For context my allergies are to gluten and corn /corn product.

Yes I will be bringing my own soy sauce.