I noticed that a fridge was being hinted at too.
Not sure how it would work for touring. A peltier-driven system would surely require prohibitive amounts of battery and/or insulation to keep it going for the 24hours+ that you need for a fridge to be worth having. Dynamo power is overrated for touring, as most touring cyclists do relatively little mileage (we can assume at low speeds if they're bringing the sort of equipment that is congruent with a fridge), and they're probably using the dynamo to power their other gadgets already. We know solar doesn't work without prohibitive panel area. Mains power correlates strongly with shops that sell food, so it's going to have to run for days without recharging. Gas-powered absorption refrigerator on a bike? That I'd like to see. I can imagine it filling the same sort of niche as the Midget Bushtrekka.
In the real world, cycle tourists tend to eat fresh foods obtained locally within a day - which you can reasonably get away without refrigeration in most weather - or use food that can be stored indefinitely at room temperatures. The most critical item for most people on here seems to be milk for their tea addiction, which keeps reasonably well in a thermos flask. It's just not that important.
Commuters can use a simple cool-bag if necessary. There's probably a fridge at work, and even if there isn't, pretty much anything will keep until lunchtime. The one thing they don't want to be doing is faffing with another gadget when they park their bike.
Obviously a cargo cycle with a refrigerated compartment is a potentially useful thing to have for delivering food. Again, rather niche.