Nervous to test out allergen foods with babes

Hes 9 months and so far I know hes good with peanut butter!

What else is there to test? And how?

Strawberries I know. How did you ladies prep it for babes? (Do you take out the little green seed thingies on strawberries btw?)

Also, do all these foods (shellfish, peanut butter, strawberries, soy, wheat etc) need to be tested out before age one?