@Donna Coker posted:This was so helpful! I have a related question. I used pasteurized egg whites in my royal icing. The icing was in the frig about 5 days before I iced this last batch of cookies. I iced the cookies 1-2 days ago. How long can my iced cookies safely sit in a container (zip lock bag or tupperware)? I was going to hand these out to friends today, but started worrying! Thank you!
Pasteurized whites are heat-treated to kill harmful bacteria like salmonella. So cookies iced with pasteurized white-icing can safely sit out almost indefinitely. The same would be true even if you made icing with regular eggs PROVIDED those eggs were salmonella- free to start. If the icing is bacteria-free to start, it's unlikely you'll cross-contaminate the icing if the cookies are sealed, and/or that any bacteria in the icing will grow (because the sugar content of the icing is so high, and that suppresses bacterial growth). The bigger question, which is independent of the icing, is how long the cookies will remain tasty before they go stale.