Canned food is safe. Commercially canned products go through a tightly regulated sterilization process that kills harmful bacteria, and cases of illness from store-bought canned goods are extremely rare. Between 1950 and 2006, 91% of foodborne botulism events in the United States were linked to home-preserved foods, not commercial products. That said, there are a few practical things worth knowing about sodium, nutrition, can condition, and shelf life.
How Commercial Canning Kills Bacteria
The canning process works by sealing food in an airtight container and then heating it to a temperature high enough to destroy microorganisms, including the spores that cause botulism. Federal regulations require that commercially canned foods reach what’s called “commercial sterility,” meaning the food is free of any microorganism capable of growing under normal storage conditions and any viable pathogen of public health concern.
In practice, this means cans are processed in pressurized retorts (essentially industrial pressure cookers) at temperatures typically above 220°F (104°C), with exact times and temperatures tailored to each product. The FDA requires that every commercial canner follow a “scheduled process” designed by a qualified processing authority, and retort thermometers must be accurate to within 1°F. The system is heavily regulated and routinely inspected, which is why commercial canning failures are so uncommon.
Botulism Risk Is Real but Extremely Low
Botulism is the fear most people associate with canned food, and it’s a legitimate concern in theory. The bacterium that produces botulinum toxin thrives in low-oxygen, low-acid environments, which is exactly the inside of a sealed can. But in practice, commercially canned food almost never causes botulism in the United States.
Of the 413 foodborne botulism events reported to the CDC between 1950 and 2006 where a food source was identified, only 37 (9%) involved commercially processed foods, and many of those were traced to restaurant preparation rather than the canning itself. Only 8 commercial canning events linked to human botulism cases were reported to the CDC in that entire 56-year span. Before a 2007 outbreak tied to canned hot dog chili sauce, no U.S. botulism case had been linked to underprocessing of a commercially canned product in over 30 years.
Home canning is a different story entirely. Without precise temperature control and validated processing times, it’s much easier for spores to survive. If you do home canning, following USDA guidelines exactly is critical.
What Happens to Nutrients During Canning
The heat used in canning does reduce some vitamins, particularly vitamin C and certain B vitamins. These water-soluble nutrients are sensitive to thermal processing, and some also leach into the canning liquid. Vitamin C is often used as a marker for nutrient loss because it’s the most heat-sensitive, but that also means it paints a worst-case picture. More stable nutrients like vitamin A, carotenoids, vitamin E, and minerals hold up well through canning and long-term storage.
For many people, the tradeoff is worth it. Canned fruits and vegetables are picked and processed at peak ripeness, while “fresh” produce may spend days or weeks in transit and on shelves, losing nutrients along the way. If canned vegetables help you eat more vegetables overall, the modest vitamin loss is a small price. You can also recover some of the water-soluble vitamins by using the canning liquid in soups or sauces rather than discarding it.
Sodium and How to Reduce It
Salt is added to most canned vegetables and beans for flavor and preservation, and the amounts can be significant. But a simple step makes a noticeable difference: draining and rinsing. USDA research found that draining and rinsing canned vegetables reduces sodium content by 9% to 23%, depending on the product. Canned corn, for example, dropped from 205 mg of sodium per 100 grams to 162 mg after draining and rinsing. Canned peas went from 261 mg to 231 mg.
Many brands now offer “no salt added” or “low sodium” versions. If you’re watching your sodium intake, these are worth seeking out, and rinsing any regular can still helps.
BPA and Can Linings
For years, the inner lining of most food cans contained BPA (bisphenol A), an industrial chemical that can mimic estrogen in the body. Public concern pushed most major manufacturers to transition to BPA-free linings, and the majority of cans sold today use alternative coatings made from materials like acrylic, polyester, or other polymers. If avoiding BPA is important to you, check the label or the manufacturer’s website, as many brands now advertise “BPA-free lining” on the can itself.
Lead Is No Longer a Concern in U.S. Cans
Older cans once used lead solder to seal their seams, which allowed lead to migrate into food. The FDA banned lead solder in food cans sold in the United States under 21 CFR Part 189.240, and modern cans use welded seams instead. This is not something you need to worry about with any can purchased from a U.S. retailer today. Imported cans from countries with less stringent regulations could theoretically pose a risk, but major importers are subject to FDA oversight.
Shelf Life and “Best By” Dates
Canned food lasts far longer than most people assume. The USDA states that canned goods will last for years, as long as the can is in good condition. The dates printed on cans are almost always about quality, not safety. A can of tomatoes a year past its “best by” date may have slightly softer texture or duller color, but it’s not dangerous.
The key factor isn’t the date on the label. It’s the condition of the can.
When to Throw a Can Away
A few physical signs mean a can should go straight in the trash:
- Deep dents. A deep dent is one you can lay your finger into. These often have sharp points and can compromise the can’s seal, especially along the top or side seam. Any deep dent on a seam is grounds for disposal.
- Swelling or bulging. This indicates gas production inside the can, which is a sign of bacterial activity. Never open a swollen can.
- Rust that has eaten through the metal. Surface rust is cosmetic, but if it’s deep enough to create pitting or holes, the seal may be broken.
- Leaking. Any can that’s leaking has lost its hermetic seal and should be discarded immediately.
- Spurting liquid on opening. If liquid sprays out when you puncture or open the can, the contents are under pressure from gas buildup. Don’t taste it.
If the food inside looks or smells off after opening, trust your senses. But for an intact, undamaged can stored at room temperature, the contents are safe essentially indefinitely, even if the quality gradually declines.
Cans vs. Other Packaging
From an environmental standpoint, metal cans are among the most recyclable food containers. Aluminum beverage cans have a global recycling rate of about 71%, compared to 40% for PET plastic bottles and 34% for glass. Steel packaging recycling rates are even higher in some regions, reaching 85.5% in Europe. Both aluminum and steel can be recycled indefinitely without losing quality, which gives canned food a meaningful edge over single-use plastic packaging.
Storing canned food also requires no refrigeration or freezing, which reduces energy use throughout the supply chain. For shelf-stable protein, vegetables, and legumes, cans remain one of the most practical and low-waste options available.