Asked by: Mickey Constanza, Hartlepool
Possibly. Yoghurt is made from the action of bacteria on milk, but this is a carefully managed process using specially selected strains of bacteria - it isn't the same as milk that has simply gone off. Yoghurt made under sterile conditions and still in an unopened tub in the fridge should normally still be safe after a fortnight. But once opened, other micro-organisms such as listeria can quickly colonise it, putting you at risk of food poisoning.
Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.