Sometimes the top layers defrost slightly. The food are still safe to store back in the freezer or defrost fully to use, a long as the contents do not go over 4°C.
Our insulated courier boxes have been specially designed for 48 hour transport time, and each pack keeps the other pack cold – a bit like when we huddle together to keep warm! In very hot weather, the top layers of the food packs can start to defrost - but it's nothing to worry about! Simply put them in the freezer and use them as usual.