Food safe electrical cabling
The FDA has a list of substances which are considered safe for food contact. It might be a bit difficult to find the correct material in that list.

This is also something you can ask the manufacturer of the cable: is you cable FDA certified?

Phoenix Contact for example advertise PP cables (polypropylene) as especially suited for food industry because:


Very resistant to cleaning agents and disinfectants 
Easy detection of contamination thanks to the light-colored outer sheath 
Halogen-free


Well the first point is probably true for any PP, the other two might be specific to the Phoenix Contact ones.