I'd guess the experience is, in fact, allergic reactions, and what you're feeling is a mild swelling of the tissues affected. Your banana allergy, given that it's particularly common with unripe bananas, is probably a latex allergy; kiwi, mango, guava, avocado, and a few other fruits also contain natural latex and should be avoided.
Chips, I'm less certain of, unless you're associating it with chips you happen to be dipping in guacamole.
ETA: Oh. English chips. That could be the oil they're cooked in; do you have any other food allergies you're aware of? (That burning sensation? Pay attention to it when you eat. I'd describe the flavor of allergic reaction as being like copper needles poking into your tongue - a spicy metallic taste. Personally I find it delicious.)
Also ETA: Try taking a Benadryl and see if the symptoms subside, provided you're not sensitive to it (dipenhydramine hcl, if looking for generics).
Also also ETA: Cup-A-Soup contains celery, which is listed as a moderately cross-reactive food for latex allergies.
http://latexallergyresources.org/cross-reactive-food - includes celery and potatoes. Thin-cut fried potato might have all the proteins in question destroyed by the frying process.
This sounds plausible, thanks!
The main things that don't seem to fit are
apart from banana, I don't think anything else gives the burning sensation
it only seems to come from food, and in particular I haven't noticed any issues with latex condoms
I've eaten many of the cross reactive foods, and regularly eat some of them, and don't associate it with any of them
But I wouldn't be surprised if none of those are actually surprising, and I could easily fail to notice if other things were associated.
No other food allergies that I know of. Benadryl seems to mean something else in the UK, but I'll try to pick up some diphenhydramine.
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