Generally, the shelf life of canned foods and preserves can reach up to five years, yet reality often proves otherwise. Production flaws, storage mishaps, or labeling errors can shorten that window and make certain products unsafe to eat. When canning goes wrong, the consequences can be serious, so it pays to know the signs and act quickly.
In practice, issues with canned sardines and other fish are among the most common problems. If a can is opened and any doubt remains about what’s inside, the safest course is to discard the product. Foodborne illness is a real risk, and botulism is one of the most dangerous possibilities linked to faulty canning. When in doubt, throw it out.
If you see this on a tomato, throw it away immediately.
Food safety begins with awareness. A visual check is essential before any use. Look for indicators of compromised integrity, especially on canned goods paired with other preserved foods. When something looks off, do not risk it. Even a small irregularity can mean a food safety problem that could lead to serious illness.
Signs that a can of sardines is bad
- The lid moves up or down after you lift it; if the seal isn’t intact, air can enter and bacteria can grow. In storage, the can should remain stable and not show any movement when touched.
- A dent in the can is visible. A damaged seal can allow microorganisms to contaminate the contents, and the food inside may not be safe to eat.
- The can shows rust from moisture exposure or other factors. Rust can weaken the metal and compromise the seal, increasing the risk of contamination.
- The can appears swollen. Internal gas buildup from microbial activity can cause expansion, sometimes accompanied by a sour, sourish odor or other unusual sensations. This is a red flag for toxins such as botulinum.
- Bubbles or foam when opening the can. This is not normal and signals gas production from bacterial activity.
- A bad or off smell. A strong, sour, rotten, or funky odor is a clear warning sign that the contents should not be consumed.
If you see this when you open a lemon, throw it away.
In any of these scenarios, the can should be discarded and not consumed. Even if the product is not past its labeled date, a compromised can can still pose health risks. When doubt arises, it is safer to err on the side of caution and dispose of the item.