The empty bag is the step most often skipped. A bag left in a sunlit vehicle or a warm store releases that heat as soon as goods go in, so the ice pack spends the first part of its cold on the bag instead of the product.
- Before loading, the liner should be clean and dry and the zip should run freely. A bag that has been sitting somewhere warm is pre-cooled with a frozen pack inside.
- Load product that is already at its target temperature. Fully frozen packs go on top and along the sides, because cold air sinks; sensitive goods do not touch the packs directly, and voids are filled.
- On the route, open the bag only at deliveries, keep it out of the sun and put nothing on top that would crush it. After a partial drop, gather the remaining goods together.
- On return, clean and dry the bag and check it for damage.
On the first runs of a new route, a small data logger inside the bag shows how many packs that route really needs.
