Any issues with copper pipes in contact with food?

Hello

A question for all you knowledgable food bods.

We are considering chilling water in a barrel washer by introducing piping into the bottom of the barrel casing, filling said piping with food grade glycol and hooking up to a chiller unit. The question would be, copper or stainless steel pipes?

My instant reaction is stainless due to its strength, but copper has a better conductivity. The pipes are not in direct food contact, but will be immersed in the water used for washing. We are talking about a low care veg washing facility.

All help appreciated