A slip sheet is a piece of paper inserted in the case to keep it from sticking to other items. It also protects the contents and prevents them from shifting around inside their packaging.
Slip sheets are used for everything from books to CD cases, but they play a significant role in the food industry. The food industry relies on slip sheets because many products come wrapped or sealed with plastic; this makes them difficult to inspect before purchase.
The slip sheet provides a protective barrier between the product and its outer packaging to be inspected without contaminating or damaging the goods inside. This makes it possible to identify problems with food products in stores before they are purchased. This means less time spent at home dealing with spoiled produce and more money saved.
Packaging companies can provide slip sheets to food processing plants and their distributors, for a fee, of course. In the grocery store environment, one way you might get your hands on them is by asking customer service for a few extras that have been returned or were otherwise removed from boxes being restocked.
In conclusion, slip sheets are an essential part of the packaging industry. They protect products inside their packaging and make it possible to identify problems with food before purchase.