Commercial kitchens
NEC 210.8(B) has required GFCI protection for every 125 V, 15 and 20 A receptacle in a commercial kitchen since 2008; the 2017 and 2020 editions broadened the non-dwelling list to sink areas generally, 250 V receptacles, and indoor wet locations. Read the edition your jurisdiction adopted.
Appliances that bring their own
NEC 422.5 lists vending machines (since 2005), drinking-water coolers and bottle-fill stations, high-pressure spray washers, and others: the appliance must be GFCI-protected wherever it stands, which the maker usually meets with a factory cord carrying an in-line or plug-head GFCI. That cord is a listed part of the appliance; replace it with the same.
Wash-down equipment
Where hoses run, the receptacle and the plug need a rating for it: NEMA 4X or IP66 enclosures on the equipment, watertight plugs and in-use covers on the wall, and a GFCI whose housing can take a spray. An in-line device in a sealed housing partway down the cord, with the plug and receptacle in a dry zone, is a common answer; a breaker in the panel is the other.
Reset behaviour matters here
Refrigeration and display cases must not stay dead through a trip caused by a wash-down cycle; a slicer or a mixer must not restart on its own. Automatic reset for the first group, manual for the second — and separate circuits so a trip on one does not take the other down.
The inspector's two questions
Is every receptacle in the area protected, and is the protection tested? A monthly log of TEST-button checks answers the second (how often).