The bottom line is there are certain ingredients when you put them together that can be a problem.

Perhaps they didn't have certain ingredients on hand, so they substituted others.

It is used to keep certain ingredients from separating out.

Cooking with certain ingredients can raise the cost of a recipe.

And, too, the baking process produces new compounds when certain ingredients react with each other.

It is impolite to pick out certain ingredients and leave the rest.

That's what I do when a certain ingredient is in season: repeat it in different ways.

And like a bad chef they seemed to think that adding more of certain ingredients would make the meal taste better.

Don't be discouraged if you can't find a certain ingredient.

This would be the case even if the rule merely prescribed certain ingredients in a product.