In social networks and popular culture, the idea has circulated that finding a dented or swollen can in the supermarket can be a stroke of luck because, aware of the condition of the product, the business should sell it at a lower price. The reality is that neither is true. A can with these characteristics may represent a health risk to the consumer.
There are two reasons why a can may be swollen. The first reason is a shock. According to Packaging Laboratory researcher Herlinda Soto Valdez, cans are made up of several layers of metallic materials and organic coatings on the inside. A can that has been hit may have suffered breakage of the internal layers and therefore loses its capacity to protect and preserve the food. It is more advisable not to buy it and not to consume it.
The academic Jesús Fernando Ayala Zavala, from the Emerging Technologies Laboratory, said that one cause of swelling is the release of hydrogen inside the bruised can. This occurs when the acids of some foods such as pineapple, tomatoes, or citrus fruits come into contact with the iron found in the steel layer of the tinplate, which leads to the production of gas and the eventual decomposition of the food.
The second reason said both academics, maybe that, at the time the food was canned, it did not undergo the thermal processing required to eliminate the microorganisms present, which accelerated its decomposition when it was already canned. Poorly processed food may contain microorganisms capable of proliferating inside the can and producing carbon dioxide, a gas that swells the can.
Finally, the researchers explained that the health risks of consuming canned food in such conditions involve gastrointestinal infections and moderate to severe intoxications, so it is necessary to abstain from acquiring products with such characteristics. However, if the can have been hit when handled by an accident, just at the moment of food preparation, it is highly improbable that it will cause any problem for our health, they concluded.