Black Spots on Onions: Safe to Eat or Health Risk? What You Need to Know

• Black spots or powder on onions are usually caused by Aspergillus niger, a fungus naturally present in soil.
• This fungus thrives in hot, humid conditions, lack of air circulation, and prolonged storage after harvesting.
• Onions with black spots on outer layers can be eaten if the inner part is firm and white after removing affected layers.
• Discard onions if black spots are in inner parts, if they feel soft, or have a foul odor, as Aspergillus niger can produce mycotoxins.
• Store onions in a cool, dry, well-ventilated place; choose firm, heavy onions with dry, undamaged outer layers.