The Soviets had a grain steriliser which (as I recall) fitted on the back of
a lorry. A pretty large gamma source, presumably Cs 137 or Co 60. I guess it
was used to kill moulds, which are pretty hard to kill, but also pretty
unpleasant. The sort of source, though, that should be kept under pretty
close control (certainly not in everyone's kitchen) given the experience in
Brazil, Mexico, where hospital cancer treatment sources ended up being
broken up in scrapyards (to the detriment of people exposed to the bits).

No comment on the "loony greenie" view on irradiation of foods, but if they
ever have an injection or other invasive procedure from their GP or in
hospital the needle, catheter, or whatever will almost certainly have been
sterilised by gamma.