So, you bought a big bulk of canned food, and you look at the expiration date – probably higher than what you thought it was.
So, how does canned food last so long? They last long because they are stored in sealed metal cans that microorganisms cannot penetrate. Additionally, directly after the can is sealed, it’ll be heated to over 100 Celsius to kill off any microorganisms that exist in the can. The also removes the air inside the can, by creating a vacuum.
Let’s dive into more detail.
How Does Canned Food Last So Long?
Canned food can last for years without spoiling and doesn’t need to be placed in the refrigerator or a freezer. How might this be possible?
The process of canning makes this possible. The metal can is sealed completely, so no germs can enter the can. Directly after the can is sealed, it is heated to over 100 Celsius or 212 Fahrenheit. This is enough heat to kill the vast majority of bacteria inside the can.
Additionally, there will be no air inside the can since the heating process created a vacuum.
It is worth noting that 100% of the bacteria will not die; there will be a very small portion left typically. This means that the shelf life of canned food is finite, and it will eventually go bad. We’ll get into how long it takes for it to go bad in the next section.
Does Home Canned Food Last Long?
Home canning often goes through a similar process in a canner that involves heat (boiling water), pressurizing, or both. Home canned food has roughly the same shelf life of regular canned food.
How Long Does Canned Food Last?
The amount of time canned food lasts depends on what type of food it is. As a general rule of thumb, low-acid canned foods last for 2 to 5 years. On the other hand, high-acid canned food lasts for 1 to 2 years.
These are just general rules of thumb under standard storing conditions. If you were to store canned food in optimal conditions, however, that could lead to a significantly longer shelf life.
How to Store Canned Food
According to the USDA, canned food can last “indefinitely” if stored properly. This doesn’t mean it will taste, smell, or feel the same after a decade. However, canned food should probably still be edible.
So, how do you properly store it? Ideally, you should store it in an area below 85° Fahrenheit(29° Celcius), which is dry.
Canned foods can be stored on a shelf, in a cupboard, or in a pantry.
General rules of thumb for canned goods
You generally do not want to purchase any canned food that is bulging, leaking, rusted, or with a deep dent because that will significantly reduce its shelf-life.
Certain food manufacturers do have “Best-By” and “Use-By” dated, which states how long it will take the food to change texture, smell, and taste; however, it still will be edible.
Categories of how long canned food can last.
If you really must know how long food can go before it may taste “off,” here are some general thresholds.
Low Acid Canned food
This includes canned meat, poultry, stews, pasta products, and soups(not tomato soup).
This also covers potatoes, corn, carrots, spinach, beans, peas, and pumpkin. According to the USDA, low-acid canned food can last for 2 to 5 years and 3-4 days after opening if stored in a refrigerator.
High Acid Canned Food
This includes canned vegetables like canned tomatoes, pickles, and canned fruit like grapefruit, pineapple, apples, peaches, plums, pears, all berries, and all foods with vinegar dressings.
These will last 1 to 2 years on the shelf and 5-7 days after opened if stored in a refrigerator.
By the way, if you’d like to learn how to make canned food, click here.
Signs Your Canned Food Has Gone Bad
There are a few key things you can look for when figuring out if your canned food has gone bad. These things can include, but are not limited to:
- A rusted, dented, leaking, or swollen can (it can also be multiple of these).
- The can is covered in mold. (you’ll want to throw these out immediately)
- The food has changed color.
- The food has an off odor.
- The food is slimy. (if it’s meant to be slimy, then disregard this)
- The food is visibly spoiled.
- The food tastes bad. (if it tastes really bad, spit it out)
For the full list of signs you can tell if your canned food has gone bad, click here. By following this list, you’ll maintain optimal food safety and won’t get food poisoning.
So, how does canned food last so long? It’s primarily due to the heating process which kills most microorganisms and makes a vacuum. Now, this means that there will be some that still lives which means that there is a certain point in time that it’ll go bad.
Depending on how you store this emergency food, it could last a couple of years to nearly a decade. Just don’t expect to open a 40-year-old can of fruit and expect great taste and smell.
Canned food should also be rotated regularly to ensure that it is consumed before its expiration date.
Canned food can be a great way to have meals on hand. However, it is important to pay attention to the shelf life and storage conditions of canned food.