In the season when new and old potatoes overlap, it's common to find refurbished old potatoes. Unscrupulous merchants cut out the sprouted parts of old potatoes, then wash, soak, and smoke them to sell them as new potatoes. These potatoes are vividly called "potatoes that can put on makeup."
When refurbishing old potatoes, they may also be soaked in a sodium metabisulfite solution because it makes old potatoes brighter and prevents spoilage. This solution is potentially carcinogenic, and its residue, sulfur dioxide, can damage the respiratory system and cause various diseases.
How can you tell the difference between truly new potatoes and refurbished old ones?
First, look at the eyes. New potatoes usually have shallower eyes, while old potatoes have deeper ones. Refurbishing cannot change the depth of the potato's eyes.
Second, pinch the flesh. When buying potatoes, you can pinch them. If juice seeps out, it means the potato is new. Although refurbished old potatoes have been soaked in a special solution, they still contain little moisture, feeling hard and inelastic when pinched.