When cooking cauliflower, add milk or lemon juice to the cooking water to keep; it snowy white.
Potatoes: Never store potatoes (white, red or sweet or yams) below 40 degrees or they will turn grey when cooked. After cutting the raw potatoes, always rinse them to remove the released starches and then they can be stored in cold water until cooked or cooked immediately and they will not become grey. Also cut with a stainless steel knife to save them from turning grey. Carbon blades cause them to darken and create an off taste in sweet potatoes.
Caution: If potatoes are baked in foil, remove foil soon after baking. Do not bake in foil and then store in the foil, as it will not allow it to cool fast enough and can cause salmonella poisoning. This has happened at buffet places that keep them in foil (warm not hot) for serving when left out for extended amounts of time.
If sprouts appear on your potatoes, brush them off and when ready to use, cut out the base of the sprout, because the sprouts are poisonous.
If bad spots (spoiled) are on your potatoes, discard the potatoes, since the flavor can penetrate thru the entire potato.
Potatoes can be stored in the refrigerator after being cooked or baked and will not turn grey, if the above tips are followed.