The shelf-life value represents the number of days your dish is allowed to be on sale before its sold or wasted.
Click the Admin Cogs
icon along the top bar.
Click Menus, Dishes and Recipes, then click Manage Dishes.
Locate the dish and click the Edit
icon to access.
Click the Labelling tab
Enter a numerical number in the section titled shelf life (this number must represent the number of days).
Click Update to save the changes.