Onions With Black Spots: Safe or Not?
Black spots on onions are usually caused by fungus and are safe only if limited to the outer skin. If the spots reach the flesh or the onion smells or feels bad, it should be thrown away.
Onions are used every day in Indian kitchens. They add strong flavour to curries, salads, chutneys and snacks, and also provide many health benefits. But sometimes we see black spots or a dark powder on onions and get worried. Many people wonder if such onions are safe to eat or if they should be thrown away, especially when prices are high.
Dr. Bharathi Kumar, nutritionist at Fortis Hospital, Nagarbhavi in Bengaluru, explains when onions with black marks are safe and when they are not. She says black spots don’t always mean danger, but we must check carefully.
The black marks are usually caused by a fungus called Aspergillus niger. This grows when onions are kept in warm, humid or poorly ventilated places. When the onion skin is damaged or moisture collects, the fungus forms dark, powdery spores, giving the onion a sooty look.
According to Dr. Kumar, onions are still safe to use if the black marks are only on the dry outer skin. If the inside layers are white, firm and crisp, you can peel and rinse the onion before cooking. But if the black fungus has entered the flesh, or the onion feels soft, mushy or smells bad, it should be thrown away. The fungus can produce toxins like Ochratoxin A, which do not go away with heat and may harm kidneys and liver over time.
To avoid risk, store onions in a cool, dry and well-ventilated place. Do not keep them in damp bags. Choose firm onions without bruises or black powder. People with diabetes or chronic illness should avoid any onion that looks spoiled.
