I am helping a friend decorate a wedding cake next weekend. She is baking and frosting the cake. I am just helping her with the fondant. She wants to use a lemon cream cheese filling for the cake. We would like to set the cake up at 3:00 pm, but the cake will not be served until around 8:00 pm.

Could someone please tell me how to calculate from a recipe whether a filling is safe at room temp or not? I remember reading something about a sugar ratio, but I can't find anything about it now.

Any advice you can give would be wonderful.

Please help me with any information you may have. Is there a business or government agency I could call for help? I just don't know where to look.

I think that the rule of thumb is two hours according to the Dairy Association.

What about using a Cream Cheese Flavoring adding to Lemon Buttercream?

American buttercreams are shelf stable because they use very large amounts of powdered sugar and fat with small amounts of liquid. The powdered sugar, which is hygroscopic, controls the water activity in the small amount of liquid.

What recipe are you using? If it's not basically an American b/c flavored with a small amount of cream cheese; then it's probably a "perishable" recipe..... To be sure, you can call your health dept. for a decision on the perishability of your specific recipe. (Or they can direct you to the correct agency.)

Henry and Henry has a sleeved cream cheese filling that is shelf stable:

http://www.wilton.com/forums/messageview.cfm?catid=6&threadid=127950&FTVAR_MSGDBTABLE=

HTH

This is a very interesting article on how high sugar (and salt) content preserves food and prevents microbial (especially bacteria and fungus) growth.

http://www.wisegeek.com/how-do-salt-and-sugar-preserve-food.htm

Water activity & microbial growth:
(Prolonging Bakery Product Life.)

http://tinyurl.com/ya8po4z

WJ Scott in 1953 first established that it was water activity, not water content that correlated with bacterial growth:

http://tinyurl.com/bmsato

Formulating for increased shelf life:
(Decreasing water activity results in hostile environment for bacteria.)

http://tinyurl.com/csu2b9

Cream cheese frosting & sugar as a preservative:
(Includes shelf stable cream cheese recipe.)

http://cakecentral.com/cake-decorating-ftopict-582086-.html

HTH

Thank you so much, JanH, Vista, and KatSuiteCakes for all of your wonderful information. Thank you for the ideas, too. I will definitely read through all of this and take a look at the recipe. Thanks, again!

Hey LetsGetCaking, How are you?
In Texas, the health department actually posted the rules for a non-perishable item. It has to have a specific pH and water activity level as described by Jan's articles. The cool part is if you can get a recipe within a specific pH you don't have to worry about the water activity level but you need to check with your state and guidelines because they do seem to vary a bit.

You can purchase pH strips online or even at pharmacies I believe. Testing the water activity level has to be done in a lab and is a bit pricey. Do a google search for PHF (potentially hazardous food) and your state and I bet you find the guidelines. It's pretty interesting stuff if you like the science of food

Sillywabbitz,

Thanks for the info about the pH strips. The more I learn about baking and cake decorating, the more I realize I don't know. It sure is fun to keep digging, isn't it?

P.S. The new cake on your website is amazing! You are so creative!

Kearnisue, hopefully someone can help you with your ganache question.