The container should have an expiration date on it, but if not you can call Wilton's number (should be on the label) and ask them. There should be an expiration date on the container. But if there's not, then it should be good for about a year unless it's been opened. Cookie Decorating Icing Recipe With Meringue Powder. Cookie Decorating Icing Recipe With Meringue Powder. Masuzi December 15, 2018. Royal icing with meringue powder pros and cons of royal icing sugar cookies royal icing using meringue powder how to make royal icing without meringue powder.