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Canned goods last for years:
Consume them and regularly replenish your emergency stockpile

Does canned food have an infinite shelf life? How do traditional metal tins compare to those made of cardboard or glass?

Canned goods are essential in emergency stockpiles, but which type should you choose?
Communicatons Adviser
Presented by: Nofima The Norwegian Institute of Food, Fisheries and Aquaculture Research
Published

In May, the Norwegian Parliament will address the White paper on total preparedness: Prepared for crisis and war.

Norwegian authorities have developed security and emergency preparedness plans in response to the current unstable global situation. They also urge households to build their own stockpiles of food, water, fuel, and other essentials to survive a week without supplies. 

Canned goods are excellent for long-term storage

What should you stock up on? Which foods store best in sheds or attics? Authorities recommend canned goods, among other options. But which type is best? And is it safe to eat a can of beans from 2016 that has been sitting at the back of the cupboard at your cottage?

For those wondering, Morten Sivertsvik, research director at Nofima, has the answers. He is an expert on extending the shelf life of food through methods like heat treatments. On one point, he is certain: canned goods are a solid choice for long-term storage.

“The whole point of canned goods is that they're commercially sterile – regardless of packaging. They contain no bacteria," he says.

Sivertsvik says that the reference temperature for producing canned goods is 121 degrees Celsius for one minute. This kills the bacteria that could make food unsafe to eat when stored at room temperature for a long time. 

"This means that even if the food may lose flavour and appearance over time, it does not become dangerous to eat,” he says. 

'Best before' often means 'not dangerous after'

Shelf life is about more than just avoiding illness. Expiry dates also ensure that the food inside the packaging maintains its colour, texture, and taste. 

For canned goods, the ‘best before’ principle always applies.

“This often means ‘also good after,’  and, not least, ‘not dangerous after.’ In other words, the food remains safe to eat even after the best before date has passed. You should use common sense. It may become discoloured and develop flavour changes over time,” says Sivertsvik.

Research director Morten Sivertsvik believes that the metal tin – which is completely light- and airtight – is the best option for preserving canned goods over time.

The 'use by' or 'expiry date' labels, however, are different.

“For food with this type of labelling, bacteria can develop after the shelf life has expired, and you can get sick from eating it,” he says. 

All canned goods – whether in metal tins, plastic, glass, or cardboard boxes – have a ‘best before’ date.

Why is metal better than glass and cardboard?

Is there proof that metal tins are better for shelf life than modern cardboard packaging?

“We don't have a basis for saying anything knowledge-based about traditional canned goods versus cardboard. We haven't conducted any scientific comparisons," says Sivertsvik. 

However, he notes that metal tins remain light- and airtight as long as they are intact. He further explains that cardboard packaging consists of multiple protective layers, including plastic and a thin aluminium layer that blocks light, making it a well-suited option.

"But it only takes a pinhole in the light barrier of the cardboard for the food to become discoloured,” he says. 

For this reason, he believes metal tins are the best option. 

“There's no better option than metal packaging when storing food over time. The canned goods are 100 per cent light- and airtight. Alternatives in glass, plastic, and cardboard can never be better,” says Sivertsvik.

Light exposure is why canned goods in plastic packaging have a shorter shelf life than other canned goods.

“In experiments with sterilisable plastic packaging, we recommended a shelf life of 6 to 12 months. The shelf life was limited by colour changes due to light and was not based on sensory changes – i.e., changes in smell and taste of the food," he says.

The research director explains that tomato and tomato-based products can be particularly challenging when it comes to colour changes over time if the packaging is not completely light- and airtight.

Create a rotation plan

If metal is the best packaging, why is it not the only option?

Sivertsvik explains that many factors influence packaging choices in the food industry. Retailers proritise high turnover rather than long shelf life and prefer packaging that is more efficient for transport and shelf space.

"And when they can sell the same products at a higher price per kilogram in eco-friendly cardboard packaging, the choice is simple,” he says.

Sivertsvik has eaten canned goods over 50 years old without any issues. However, he does not claim that canned food lasts forever. 

“The ones I ate were definitely 'best before' – so some replacement in emergency stockpiles can be sensible, regardless of the shelf life of the food,” says Sivertsvik, offering the following advice for private food stockpiles:

“Consume them as they approach their expiry dates and replace them with new products with new shelf life. Have a rotation plan – whether it's water, dry goods, or canned goods. And fill your stockpile with food you actually like to eat.”

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