it does not matter what you build it off as long as it can be properly cleaned before use.
yes stainless is the better option as it is easy to clean and if it is shiney it shows up any muck. but there is nothing stopping you using a plastic barrel cut in half.
now i am certain that loads of beekes are going to blow there top for that statement quoting millions of elf and safety regs and food regs. and to tell you the truth alot of them are right ethicly but not legaly.
i had the council food inspector round at the rabbit hutch ( our house is very small terrace) and he mate the elf and safety bod due to registring as a food producing business they do that.
they were more intrested in drinking my coffee and chocy bickies
there point of view to my set up was remove every thing from the kitchen work tops , inc the microwave and completely wash and scrub the work tops. mop the floor and remeove the kitchen floor mate, and give the cupboard doors a wash to.
now as for my equipment.
we looked at four items i have avalible to use and his comments.
9 frame radial extractor, german made and made out of stainless."fine just wash it out"
4 frame tang extractor GALVANISED TIN PLATE 60 YEARS OLD, RE-POWDER COATED THREE YEARS AGO, LOOKS TATTY, "YEP, ok just give it a good wash first"
Home made apple press made from cut up gas cylinder and powder coated white 8 years old, " wow thats impressive, i will have to see if i could make one"
burco boiler, "fine, but i would try to remove the scale at the bottom first"
clothes spin drier, " realy , for cleaning honey?"
large electronic shop scales. "take them down to the council offices for the weights and measures people to check over to make sure they are ok, i dont know what they charge for them"
and finaly a few other none stainless foody items. wooden beer barrels and wine casks, wooden cheese molds, there are loads of things, but i would try to start with stuff from the food indudtry, a plastic barrel that contained orange juice would be a good start rather that and oil drum