Chromium in stainless steel is “stainless” because it quickly oxidizes to chromium dioxide which creates a protective barrier to further oxidation and therefore inhibits oxidation of the steel.
It is completely inert and non-toxic. We use stainless steel extensively in the pharmaceutical industry and it it completely approved for use in food preparation...in fact, it is preferred for both applications over any other material.
It is not an issue in the application of electro-cleaning as you proposed using it for. Any chromium released from the plate in the process will not become airborne as vapor and will react in solution to become the inert chromium dioxide form.
Further, chromium is a mineral that humans require in trace amounts. Chromium is known to enhance the action of insulin, a hormone critical to the metabolism and storage of carbohydrate, fat, and protein in the body
People often confuse trivalent (chromium 3+), which is biologically active and found in food, and 2) hexavalent (chromium 6+), a toxic form that results from industrial pollution. This application will not create the toxic form since it does not produce the high levels of heat required to make it.