A customer of mine ordered a dozen cookies with royal icing. The cookies were outlined in black and filled in with red and white. I made Dr Seuss hat cookies. They made it all the way to its destination. When the customer opened them up they said they are gorgeous but that 6 of them the red bleed into the white. They were dried very well before I shipped them so I'm thinking the heat or humidity in the box caused this. Has anyone else experienced this? If so how did you rectify the situation? How do I prevent this from happening again?

Any suggestions will be greatly appreciated.

About the only way to keep humidity out of a closed box would be to vacuum pack the cookies. I shipped some items last Christmas and used the vacuum zipper bags that you can buy at the grocery store.

What machine do you have to seal the bags?