This would flag up the changes and alert customers with allergies and intolerances that they should check the ingredients for changes.

I have food intolerances and need to check product labels when purchasing a new food product. I, therefore, expect recipes to be the same each time I buy that product afterward.

However, when a store changes the recipe, there is often no acknowledgement of this, meaning that, people with allergies and intolerance like me, may buy and eat something harmful to them without realising. A "New Recipe" label would alert us the ingredient changes.