I haven't seen those exact valves, but they look like a combination ball valve and bulkhead fitting. An option would be to purchase a bulkhead fitting separately and then use the valve of your choice.
from the color, I would be guessing that the OP valves are polysulphone which can be food rated. PVC is in lots of general plumbing with good variety in sizes and stainless steel for food both are readily available. As with everything wine stay away from brass.
The shop people get lots of parts from Granger, I catalogue order lots of pilot plant parts from Omega Engineering (I like the technical specs since I don’t have an engineer degree). Practically speaking your local plumber who is 40 ish has repaired something like your tank and sourced the parts.