Updated: Apr 21, 2020
Though onions have more shelf life when compared to other vegetables when peeled it becomes more vulnerable and prone to immediate spoilage.
Many times we chop extra onions, especially the previous night to use them for the next day. You must have noticed that the diced onions when stored open for a more extended period in the chiller let out more water and freshness reduced. The condition occurs once we peel the onions. The several layers of the onion’s paper skin protects itself from microbes as well as from the sunlight. Hence it is always suggested that the raw onions are to store under dark, dry and netted bags. I understand that it is a task to peel those skin during the wee hours, but here are the effects of the peeled onions when stored open for a more extended period.
According to the National Onions Association (NOA), Bacteria’s contaminate onions once exposed and left as it is. They will get oxidised further leading to a host of health issues. Hence, advised to cut and use them only when needed before cooking. It is dangerous to cut an onion and use it to prepare the next day, become highly poisonous for even a single night as it creates toxic bacteria which severely causes adverse stomach infections.
Image from Wiki How
According to Nutritionist Parmeet Kaur, peeled onions when stored becomes much soggy due to refrigerated conditions due to an increase in bacterial growth and hence decaying. Hence if you notice from the above picture, the freshness, colour and flavour content is reduced as well. The USDA confirms that the onions can lengthen its shelf life up to 30 days if stored properly. They also indicate that the shelf life of the refrigerated bulb onions peeled, cut in half, wrapped in a paper towel and sealed tightly in plastic wrap can be for 14 days. Just make sure to eliminate as much air as possible from the bag and seal tight.
Image from Cookinglight.com
The NOA suggests that the best way to store peeled (whole) onions is to wrap them with a paper towel separately in the chiller. Another best storage method is to store them in a sealed container under proper chiller conditions. Else the aroma of the onions spread throughout the fridge to contaminate other store food products with its strong smell. A similar case occurs with Garlic.
Bottom line, no matter whichever way of practice you follow, one must be sure to follow proper storage techniques to ensure cooking and consumption of nutritious and healthy veggies. Convenient methods do help in the process of fast food and time management, but this will not help us in the long run.