Is It Safe To Eat Rusted Canned Food?
There are many canned pantry items that are just as good as fresh, and they are fantastic shelf-stable staples to keep on hand for any dinner emergency. Unfortunately, while canned foods can last a long time when stored correctly, it won't keep food edible indefinitely. This is especially true for cans that are damaged.
Take rusted cans, for instance. Rust usually will form on cans that have been left in an environment that's too moist or humid. If a can is extremely rusted to the point where the metal has thinned or holes have formed, it should always be tossed, no questions asked. When a can is compromised, bacteria can easily enter and begin growing. The most dangerous of these is Clostridium botulinum, which creates a toxin that can cause severe symptoms such as paralysis, trouble breathing, and death. This is one reason why it can be unsafe to eat from dented cans because deep dents can compromise the can's seal and introduce bacteria.
Although eating food from rusted cans is usually not recommended, there is an exception. If the rust can easily be rubbed away, leaving no damage on the can, it should be safe to eat from. However, if you open the can and notice rust on the inside, even if there is no external damage, the food isn't safe to eat. Not only would it taste disgusting, but rust (iron oxide) is not safe to consume. In fact, ingesting rust can lead to iron toxicity, resulting in numerous health issues such as nausea, joint pain, and abdominal pain.
Tips for safely storing canned goods
If you're planning on storing canned goods for a long period of time, corrosion and rust can be a serious problem that some folks might not consider. Ideally, canned goods should be stored in a dark, dry place where moisture can't affect them. This means storing them away from pipes that could potentially leak or basements that could flood. Some folks can have a harder time preventing damage, as their home locations may be subject to highly humid or salty air. In these places, canned goods are more prone to rust and corrosion. If you're in an area like that, checking your canned goods regularly is essential. Although things like paraffin wax and mineral oil are sometimes used to try and prevent rust in these conditions, this is often more of a hassle than anything, and paraffin wax is highly flammable.
Something else to consider is the temperature of the environment where you store your cans. Optimally, canned goods should be kept between 50 and 70 degrees Fahrenheit. Never store them in an area where they can freeze and potentially rupture from expansion or in an area of extreme heat, as temps above 75 degrees Fahrenheit can cause nutrient loss. Similarly, the USDA states that temperatures over 100 degrees can damage canned goods and increase the risk of spoiling.
Likewise, you'll want to watch canned foods that are high in acidity, such as canned tomatoes, because these can corrode the can from the inside over time. It's recommended that these items be used within 18 months for the best quality. However, low-acid foods like canned meats can last up to five years if kept undented, rust-free, and at a stable temperature.