I live in central London and see this a lot in independent cafes and brands and not so much in the chaîns (eg in Starbucks the people who take your order and your money are different from the people who prepare your drink.)
But the standard independent approach seems to be: One person behind the till / display counter. They will wear gloves and will handle your food directly with the gloves and put it in a container or bag (whatever it is - say it’s a piece of cake or quiche.)
Then they will hand you the bag and tell you how much it costs. You give them the money; they take the money in their still - gloved hand and rifle through their till to give you the change.
Then the person in the queue behind you orders and they handle the food with the same gloved hand that took your money and gave you your change.
Considering money is one of the dirtiest things you can handle AIBU to bring this up every time I see someone doing it?