Putting It Together

Raw potatoes: keep them somewhere cool, dark and dry (above about 6°C), not in the fridge and not in the light. The Food Standards Agency advises against keeping raw potatoes in the fridge if you will roast or fry them, because the cold raises the amount of acrylamide that forms when they brown. Light turns the skin green and makes sprouts, and the green and the sprouts contain a natural toxin (solanine) that is bitter and can upset your stomach. Cut away sprouts and any green patches generously; if a potato is green all over, or tastes bitter, throw it away. Cooking does not remove it.

Go for gold. When starchy foods such as potatoes are fried, roasted or baked at high temperatures they form a chemical called acrylamide, which the Food Standards Agency says could raise cancer risk. Its advice is to cook to a golden yellow, not dark brown, and to follow the packet instructions on bought chips and roasties. A balanced diet matters more than any single food, so this is a nudge about colour, not a reason to avoid potatoes.

Foil and baked potatoes: a cooked potato wrapped in foil and left to cool or keep warm at room temperature can let the bacterium that causes botulism grow, because foil shuts out air. Cases are rare but serious. Take the foil off as soon as the potato is baked, don't leave baked potatoes out for more than about 4 hours, and chill leftovers (unwrapped) in the fridge.

Hot oil and hot fat need care: never leave them unattended, never use water on a fat fire. Cooked potatoes: cool them quickly (spread out, within 1 to 2 hours), keep them covered in the fridge, and eat them within 2 days. Reheat until steaming hot all the way through, and only once. (This is the general chilled-leftovers advice relayed by local-authority food-safety pages; unlike rice, potatoes have no special rule of their own, but they are starchy, so they are treated with the same care.)