Refrigerating chopped onion, ginger, and leftover rice won’t harm your health

By: Nabeela Khan
May 6 2024

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What’s the claim?

A Reel on Facebook claims that refrigerating garlic, ginger, and onions can be harmful for human consumption. It makes the following claims: 

1. Mold in garlic can cause cancer. 

2. Refrigerating chopped onions can increase the starch size of the substance, which can damage kidneys and pancreas.

3. Refrigerating peeled ginger may harm the kidneys. 

4. Cooked rice, when refrigerated, develops mold very quickly as the starch level goes up, and it starts damaging your gut, pancreas, and kidneys.

A Facebook Reel claiming that how refrigerating ginger, garlic, onion and cooked rice may harm health. (Source: Facebook) 

Similar posts can be found here and here. 

What did we find?

The U.S. Food and Drug Administration (FDA) stresses that properly storing food can help prevent foodborne illnesses and that refrigeration slows down bacterial growth. “Foods that require refrigeration should be put in the refrigerator as soon as you get them home,” it said. 

Speaking to Logically Facts, Haripriya N, executive nutritionist at Cloudnine Hospital, Chennai said, “The claim that refrigerating peeled garlic, ginger, onions, and other foods can be toxic is not supported by scientific evidence. In fact, storing these foods in the refrigerator after processing, like peeling and storing them separately in proper containers can help preserve their freshness and extend their shelf life, reducing the risk of spoilage and foodborne illnesses.”

Claim 1: Peeled garlic gets mold easily compared to non-peeled garlic, which can cause cancer

A peer-reviewed publication by the University of California, Agriculture and Natural Resources states that garlic — softneck and hardneck — can be stored for different durations under different conditions. For instance, under commercial conditions, softneck garlic can be stored for up to nine months, while hardneck garlic can be stored for up to six months under ideal conditions.  

The paper states that storing garlic at home in the refrigerator is not suitable as it stimulates sprouting. “When stored too long, the garlic cloves may shrivel or begin to sprout. Neither is harmful, but both indicate that the garlic is not at its peak quality,” it reads.

The publication further states that “canning garlic is not recommended.” However, it does suggest ways to freeze and store peeled garlic.

Haripriya explained, “The home refrigerator (typically 40 degrees fahrenheit or four degrees celsius) is not suitable for long-term storage of garlic as it might start sprouting and lose its quality, but it's not harmful." She added, “There is no evidence to support the claim that refrigerated garlic becomes toxic.” 

According to the International Society for Horticultural Science, “A reasonable expected storage life of commercially peeled and modified atmosphere packaged garlic is 3-4 weeks at 0°C, 2-3 weeks at 5°C, and 1-2 weeks at 10°C”. The ideal temperature setting for a refrigerator is between 1.7-3.3°C.”

Speaking to Logically Facts, Malavika Siddharth, nutritionist, gut health advisor, and co-founder of Hello Tempayy, a startup that sells ready-to-eat food, said, “Peeling garlic and keeping it in the fridge may sometimes cause it to mold faster, as the outer coating is a protective layer. But if someone chooses to store it for easy access in airtight containers while ensuring it gets rid of extra moisture, it will not turn toxic or poisonous.”

Nutritionist Dr. Amita Gadre also shared a video to explain that while chopped onions can get spoiled very quickly, it doesn’t cause cancer. 

Claim 2: Onions shouldn’t be stored in the fridge as it can damage the kidney and pancreas

This claim has been doing the rounds for the past few years. US’s National Onion Association debunked the claim, stating, “When handled properly, cut onions are not poisonous. After being cut, onions can be stored in the refrigerator in a sealed container for up to seven days.”

Responding to this Haripriya said, “Refrigerating peeled onions or storing cut onions in the fridge is a common practice to keep them fresh for a week and prevent them from spoiling quickly. As onions sprout and form mold in the raw unpeeled onions due to high moisture, it is advisable to peel or cut the onions before refrigerating." 

“There is no credible scientific evidence to suggest that refrigerated onions can be toxic to the kidneys or pancreas,” she told Logically Facts. 

McGill University’s Separating Sense from Nonsense post highlights that onions are not prone to bacterial contamination. It states that onions have a variety of sulfur compounds which have antibacterial activity. The blogpost suggests that one should practice safe food-handling techniques.

“Onions are pungent and can permeate into the environment. This is a good reason not to chop and store them in the fridge for too long. But storing and refrigerating them is not toxic or poisonous,” Malavika said. 

Claim 3: Ginger, when peeled and refrigerated again, gets mold and may harm kidneys

A blog post by the University of California, Los Angeles, listed ginger among the "kidney-friendly options". 

Rubbishing the claim that refrigerated ginger can become toxic, Haripriya said that ginger paste or minced ginger can be refrigerated in a breathable container. 

Malavika highlighted that a lot of scare-mongering opinions are based on animal studies, cell studies or personal experience. “The strongest evidence for such arguments is meta-analysis of human randomized control trials,” she said, adding, “Who is doing these studies, and how are they isolating that it is specifically related to ginger, garlic, or onion and associating it with kidney failure or pancreatic failure?”

According to Iowa State University blogpost, “Fresh, unpeeled ginger can be kept on the counter at room temperature for 1-2 weeks but is better kept in an airtight container/bag in the refrigerator crisper drawer where freshness can be retained for 4-6 weeks. Leftover peeled ginger will stay for 2-3 weeks if tightly wrapped and stored in the refrigerator.” 

Claim 4: Cooked rice shouldn’t be refrigerated as it could catch mold and damage your gut

We contacted award-winning dietitian, writer, and nutritionist Ursula Arens, who said, “Once rice has been cooked, it should be consumed. If this is not possible, it can be chilled in the fridge for a short period of time, but it must be completely reheated prior to consumption.” Explaining the science behind refrigerating rice for a shorter duration, Arens said, “There is a risk of cooked rice becoming contaminated with Bacillus cereus which can cause vomiting and this would be a higher risk in very young children or those who are unwell.”

Haripriya, too, said that rice can only be refrigerated for a short duration. She added, “There is no scientific evidence to support the claim that refrigerated foods like these can turn toxic or pose health risks unless it's not stored or handled properly. It's important to rely on credible sources and scientific studies when evaluating food safety and nutrition-related claims.”

The National Health Service (NHS) advises cautious storage of rice. “The longer cooked rice is left at room temperature, the more likely it is that the bacteria or toxins could make the rice unsafe to eat. Keep rice in the fridge for no more than 1 day until reheating.” 

Author and food science blogger Krish Ashok in one his videos also stated that “plain cooked/steamed rice can sometimes be infected by a bacteria that doesn’t mind low temperatures, so it’s best to consume it within 1-2 days.” He added that “Indian food is uniquely fridge-friendly because it tends to be spicy, salty, and sour — three conditions microbes absolutely hate”. 

According to the Centers for Disease Control and Prevention (CDC), “Refrigerate perishable food (meat, seafood, dairy, cut fruit, some vegetables, and cooked leftovers) within 2 hours.”

Verdict:

There is no scientific evidence to support the claims that peeled and chopped onions, garlic, ginger, and cooked rice, when refrigerated, are harmful to human health. In fact, the CDC and USFDA recommend refrigerating cut fruits, vegetables, and cooked leftovers.