I just got licensed for home baking (yay!), but with a home processing license here, I cannot make any products that require refrigeration for safety reasons as a finished product. There is a difference between refrigerating for quality (melting, etc. in hot weather) vs. needing refrigeration in order not to go bad and spoil. I'm sending in a few frostings just to be on the safe side for water activity level testing, but I'm trying to keep costs down. Are any of the following KNOWN to be shelf-stable with low water activity levels (and please don't say just from experience, it has to be known to be tested low). Thanks!
1) Wilton buttercream frosting made with 1/2 shortening, and 1/2 butter
2) Wilton buttercream frosting made with 100% butter
3) Cream cheese buttercream frosting (made with 8 oz. cream cheese, butter and sugar) - this is one that I know comes up a lot. Apparently 8oz. of cream cheese can be stabilized with 4 cups of sugar, but I want to be sure).
4) Vegan buttercream - same as Wilton's recipe, but using Earth Balance butter and soymilk instead of regular butter
5) Clothespin cookie filling - made with 1 cup milk cooked with flour, then mixed with butter, marshmallow cream, a little shortening and superfine sugar. This one melts at room temp but I'm not sure it's "unsafe" so it needs to be tested.
Thanks so much!