A can-do attitude: Swetha Sivakumar on the merits of tinned treats

Canning has a history that goes all the way back to the French general Napoleon Bonaparte, who wanted to feed his tropps better amid long-drawn-out battles in faraway lands. It remains a simple, wholesome way to preserve foods. It’s a real time-saver in the kitchen. So why does it get so much flack? It really shouldn’t, says Sivakumar.

“An army marches on its stomach,” said Napoleon Bonaparte. Or at least we believe he did. What we do know is that the 19th-century French general and later emperor recognised that being well-stocked on food supplies was crucial to troops’ victory.

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Drying, fermenting and pickling were common then. But a large army needed better sustenance if one was to keep morale up. So, in 1795, Napoleon offered a reward of 12,000 francs to anyone who could find a new way to preserve food that would retain more of its original flavour and texture.

It took 15 years, but a chef and confectioner named Nicholas Appert finally won the prize. In an 1810 treatise, The Art of Preserving all Kinds of Animal and Vegetable Substances for Several Years, he laid out the basic techniques for canning – seal food in containers and then submerge those in boiling water for a set time, to vastly extend the life of the preserved food.

More than two centuries on, while there have been technological advancements that allow for large-scale canning, Appert’s basic principle still guides the process. And we’ve since learnt why: While the sealing prevents contamination, the boiling water destroys microorganisms already present in the sealed container, preserving the food for longer.

Canning is an inexpensive process, it makes preserved foods easy to store, and is a real time-saver in the kitchen. So why does it get so much flack? Most opponents are not truly opposed to the process itself – they’ll happily reach for a tin of condensed milk, for example, when making a dessert. But canned tomatoes, chickpeas and the like are viewed with suspicion. There is a sense that, since they are not fresh, they are not nutritious, and / or that they are loaded with salt and preservatives. Do these accusations hold merit? Here’s what really matters, when it comes to canned goods.

For any canned product to taste good, the original produce must have been packed at peak ripeness. Canning factories are often located close to farms, so vegetables such as green beans and tomatoes are canned within hours of harvesting. The high heat might mean that water-soluble vitamins such as Vitamin C and Vitamin B are lost, but no more than if one had pressure-cooked the same foods at home. In fact, canned foods retain proteins, minerals and fat-soluble vitamins. In some cases, nutrients such as the lycopene in tomatoes and the Vitamin A in pumpkin become more concentrated.

Canning doesn’t necessarily require salt, sugar or other additives either. That said, ready-to-eat canned foods such as soups or curries might have more salt in the recipe to compensate for the loss of flavour that typically results from extended boiling.

Most canned ingredients (chickpeas, beans, vegetables) are packed with just two additional ingredients: water and salt. And there are reduced-salt and even salt-free options available for many. With fruit, instead of buying those canned in heavy syrup, which can be high in sugar and calories, look for fruits canned in their own juices.

Sometimes, it is not the food but the container that causes fear. With canning, there is widespread and justified fear over the use of bisphenol A (BPA), a chemical once commonly used to line cans to separate the metal from the food. In 1992, it was found that BPA mimics oestrogen and could potentially have endocrine-disrupting effects on the body. Exposure to BPA was also found to affect the brains and the prostate glands of foetuses. Many companies have since switched to BPA-free cans, lining cans with acrylic and polyester instead.

Another fear, when it comes to canned foods, is the risk of botulism, which is a fatal condition linked to certain kinds of bacteria. The US Centers for Disease Control and Prevention, however, has found that it is home canners, not commercial ones, that have been the primary cause of botulism outbreaks. As early as 1919, manufacturers worked with US government agencies and scientists to establish a Botulism Commission, which led to the development of strict regulations in the canning process. The botulism toxin, where present, is killed when exposed to 85 degree Celsius temperatures for five minutes. Its spores do not survive when exposed to 120 degree Celsius temperatures for more than three minutes. Many canned foods today are pressure-canned at 120 degrees Celsius for a minimum of 40 minutes, keeping them safe.

Our scepticism about canned foods seems especially outdated when entire shelves in grocery stores groan under the weight of ultra-processed packaged foods high in fats and sugar. I believe it is healthier to walk past flashy, addictive options and head to the back of the store for canned products that are wholesome and more nutritious. They can help one eat more healthily too, allowing the busy homemaker to whip up a chickpea sundal, rajma salad or carrot raita in under 10 minutes.