I am opening a new cupcake bakery and I wanted some suggestions on developing an HACCP plan. Do any of you test your icing water activity levels to determine stability? I found some articles (some by the FDA) saying that if you can keep your icing below .80 aw that it would inhibit microbial growth. They even suggested different tools with which you could test water activity. It sounds like just adding enough confectioners sugar you can bring the water activity level down to make most icings (Cream cheese being my primary concern) stable. What are your thoughts?