While fresh fruits, vegetables, and meats have a relatively short shelf life, these same ingredients can last for years if canned. Canning is a process of preserving food in an airtight jar or tin and has been around for around 200 years.
Nowadays, there is a large variety of canned food that can be found in almost every grocery store. Canned food generally lasts for between 1-5 years, although in some cases, it can last for much longer if it is stored correctly.
Although it is unlikely that you will ever keep a can of food long enough for it to spoil, it is important to recognize what spoiled canned food looks like as it can be dangerous to consume.
You may have noticed black spots in your canned food and be unsure whether it’s still safe to consume. Let’s take a look at what these black spots are.
Black Spots in Canned Food
Black spots can form in canned food as a result of the reaction between copper and sulfur during the canning process when the food is heated to high temperatures. It is essential that the food is heated to high temperatures to preserve it.
These black spots are generally too small to be noticeable, but in some cases, they can grow larger and become visible to the human eye. While these black spots may look unappetizing, they are safe to consume.
If you are unsure whether the black spots are due to the reaction between copper and sulfur or something more nefarious, smell the contents of the can.
Canned food that has spoiled will often smell foul, whereas you will not be able to smell the copper and sulfur spots. You can also check the outside of the can to see if it is dented or damaged in any way.
An unopened can should never leak. If the can is damaged, you should discard the food or return it to the shop it was purchased from for a refund. If the can is bulging, this is also a sign that its content may have spoiled.
Additionally, the food should not be discolored or spurt liquid or foam when the can is opened.
In addition to these tips and tricks for knowing whether a can of food has spoiled, you should always check the expiry date. The expiry date will always be printed on the label or the can to indicate how long the food inside should last.
Discard cans of food that are past their expiry date to avoid eating spoiled food that may make you ill.
You can avoid this wastage by checking the dates on canned food when you are grocery shopping and choosing the cans which have been manufactured recently and will last for years.
Discarding Spoiled Food
If you notice one or more of the signs indicating spoiled canned food above, it’s important to discard the food safely. Put on a pair of latex gloves before handling the food and avoid splashing it onto your skin.
Rather than throwing the food into your dustbin where it could release harmful spores, place the food into a bag that can be sealed. A Ziploc bag will work well. Seal the bag and then place the sealed bag into another bag for good measure.
Seal the second bag and place it in an outside dustbin that is not intended for recycling. Ensure that the dustbin is closed so that pets cannot get the bags inside.
After you’ve discarded it safely, you should wipe any food spills with a bleach and water solution. Mix ¼ cup of bleach with 2 cups of water. Then, wash your hands with warm water and soap for at least 2 minutes.
The Bottom Line
Small black spots in canned food where the can is not damaged or past the expiry date are generally nothing to be concerned about.
However, you should never consume black spots that appear furry, as they are probably mold which can be harmful.
If you suspect that the canned food has spoiled, discard it, or return it to the store where it was purchased for a refund.
Some brands will even reimburse you if you photograph the food and send the pictures to their consumer helpline with a description of your experience.
A simple Google search will usually reveal a brand’s consumer helpline contact details which are generally listed on the brand’s website.