It cost money and manhours to comply with such regulations. Just think of the hike in insurrance should companies be liable in a mixup.
Are you sure consumers want to float that cost?
It can be done, sure, by force.
Might give a false sense of security. Luring people with serious foodallergies to eat more out.
Healthier,better and cheaper to make your own food. esp if Greggs is on the list.
Guessing there is a market for "clean" food that could be adjusted for allergies aswell. In the same fashion as fairtrade or ecological food.
I have some foodallergies, but nothing serious. I get stung now and then when eating out. Mostly from my own stupidity.
Most people do not know if they have any allergies. Those that know they are hypersensitive should not risk it anyway. They make their own food.