According to this email sliced raw onions are a “magnet for bacteria” and should not be stored in the fridge even for brief periods. The fact is that onions are not especially prone to bacterial contamination. In fact, quite the opposite. Onions feature a variety of sulphur compounds that have antibacterial activity.

Harvesting and storing onions properly will help keep the veggies for months. Mushy rot in onions is the Achilles’ heel of stored Allium. It will not only rot an infected bulb, but the disease spreads readily in storage situations. One onion with mushy rot can spoil an entire harvested crop.

Whole onions and shallots are best stored in a cool, dry, dark and well-ventilated room. Peeled onions can be stored in the fridge for 10–14 days, while sliced or cut onions can be refrigerated for 7–10 days. To keep them even longer, freeze them in a resealable bag or airtight container.

“Yes onions should be cut fresh and cooked right away. However, they don’t turn toxic as their acidic pH inhibits microbes and bacterial growth.” She did warn that cut onions left outside the refrigerator may have lost their freshness and should ideally not be consumed the next day.

Like this: “Please remember it is dangerous to cut an onion and try to cook it the next day, it becomes highly poisonous for even a single night and creates toxic bacteria which may cause adverse stomach infections because of excess bile secretions and even food poisoning.”

People with onion allergies may experience red, itchy eyes and rashes if an onion comes into contact with the skin. People with an intolerance to onions may experience nausea, vomiting and other gastric discomfort.

Red and yellow onions are richer in antioxidants than other types. In fact, yellow onions may contain almost 11 times more antioxidants than white onions ( 25 ). Cooking can significantly reduce levels of some antioxidants ( 26 ).

You should eat onions raw rather than cooked to get the most sulfur compounds from them.

What if onions are cooked? Cooking an onion will kill the salmonella bacteria, Warriner said. The real risk is that the bacteria could be on the outside of the onion, which could spread to kitchen surfaces and other ingredients when it’s chopped, he added.

Twelve ways to get rid of the smell

1. Drink water. Drinking water after meals can wash garlic or onion remnants from the tongue or between the teeth.
2. Brush and floss.
3. Use a tongue scraper.
4. Rinse with mouthwash.
5. Eat fresh fruits and vegetables.
6. Eat herb leaves.
7. Try apple cider vinegar.
8. Have a cup of green tea.

What are the symptoms of an onion allergy?

• hives or a rash anywhere on the body.
• tingling or itching in the mouth.
• swelling of the lips, face, tongue, or throat.
• nasal congestion.
• difficulty breathing.
• nausea and vomiting.
• diarrhea.
• stomach pain.

Summary Onions, especially raw onions, may cause acid reflux and heartburn symptoms by relaxing the lower esophageal sphincter. In addition, onions are high in fermentable fiber, which may promote acid reflux symptoms.

Onions. Onions contain a natural sugar called fructose. Like raffinose and sorbitol, fructose contributes to gas when bacteria in the intestines break it down.