I was wondering if there is a way to do a reheat post fry. It depends a lot on what the wheat containing product is of course. Or if you can make all of your products wheat free?
So for example, I'm not sure why this came to mind, not wheat but I often make pakoras which are an Indian snack made from chickpea flour, spices and pretty much whatever you have to hand. (I always make them with vegetables but they don't have to be.) When I make them it's a bit of a labour of deep frying love and it stinks out the house etc. So I make LOADS, freeze them and reheat after defrosting in the oven or air fryer. Thing is, they actually taste better on reheat as they are crisper and less oily.
Depending on how "high end" your restaurant is and how many gluten free sales you make, you might be able to buy in or make in advance pre prepped part or fully cooked fried items for your wheat free to reheat in an oven which is less risky. Not ideal but the only options I can think of are:
Separate fryers - probably your best option without changing your menu but not without risk; you need to train your staff well to not just use whatever they like. If you can make the gluten free fryer in a separate area so it's clear the person is using the right one (e.g. a small bench top one) that would help. But heating it up will be a hassle. I foresee that compliance with that might be difficult.
Segregation by time - might be hard unless you're getting orders in advance or can part or fully cook and reheat wheat free by doing them first and accepting there might be some waste.
Disclaimer - I wouldn't go there. Strictly speaking you could be legally fine in the UK at least if it's <20ppm gluten but I don't think you can claim both "wheat free" and "may contain" legally or ethically nor could you be sure it could be <20ppm.
Remove the allergen - if it is batter, you can make some really decent gluten free batters. Why not try and make all of your fried foods gluten free?
Offer a different cooking method - you've not shared what product it is but could it be a pan fried meal instead for your gluten free consumers?
One thing to be super wary of with your staff is that many people will order gluten free for reasons apart from anaphylaxis but it is possible to have a true anaphylactic allergy to wheat. If someone orders a wheat free order, it might be they have a life threatening allergy, it might be they have the chronic and immediate health impacts of Coeliac disease, it might be they have been formally diagnosed with a wheat intolerance or they might be on the latest fad diet. Probably 9 times out of 10 it won't be anaphylaxis if they get it wrong. But they won't know which order that would be. I can imagine a situation where a cook / chef prepares in the same fryer because it's easier and cuts a corner and repeatedly "gets away with it" until that customer with a REALLY serious allergy shows up....
