Why You Shouldn’t Store Half-Full Open Cans Of Food In Your Refrigerator

The biggest concern is metal leaching, a process where the can’s metallic material seeps into your food over time. Once you pop a can open, its insides are exposed to air and oxidation can speed up the transfer of metals into your meal. This is particularly problematic for acidic foods, such as canned tomatoes, which can accelerate the breakdown of the can’s inner lining, increasing the risk of contamination.

As a 2019 study warns: “Food from can packaging should not be exposed to oxygen for a long time, especially when it has been opened because it will increase the leaching of Fe and Zn [iron and zinc] metals from the packaging into food.” 

While there isn’t overwhelming evidence that this poses a severe health risk – the body actually needs very small amounts of zinc and iron to function healthily – it’s still something to be mindful of. Even if the leached metals don’t harm you, they might alter the taste and quality of your food. As per Michigan State University, “high-acid foods may leach metal or metallic flavors from cans,” meaning your leftovers could end up with a nasty, tinny aftertaste. Blurgh. 

In recent decades, there has been another danger lurking in food cans: Bisphenol A (BPA), an industrial chemical that was often used to line the inside of cans to prevent leaching and spoilage. According to a 2020 study, it is “well established that canned goods are a common source of BPA,” plus the chemicals are known to have “adverse health outcomes.” For instance, extensive research has shown that BPA can mimic estrogen to interact with estrogen receptors, which may disrupt normal hormone function.

Some commentators have suggested that storing food in opened cans increases the risk of BPA leaching into the food, although there’s limited evidence to support this. Fortunately, there have been efforts to phase out BPA in food-contact materials, most notably in the European Union, although US health authorities still contend the material is safe in moderation. 

The solution is simple and will take you 10 seconds: transfer any unused canned food to a clean, airtight container before refrigerating. According to the US Department of Agriculture, unused food from a metal can be stored in the refrigerator, but it must be transferred in a “food-grade glass or plastic container” and must be used within four days.

While it may add to your pile of washing up ever so slightly, taking the extra step to transfer your leftovers to a proper container is a small effort that may pay off in the long run (at the very least, it won’t do you any harm). With growing concerns over food safety and chemical contamination, it’s always better to err on the side of caution.  

The content of this article is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of qualified health providers with questions you may have regarding medical conditions.   

All “explainer” articles are confirmed by fact checkers to be correct at time of publishing. Text, images, and links may be edited, removed, or added to at a later date to keep information current.