Canned food, be it vegetables, fish or legumes, is one of the foods with the longest shelf life. This is because they do not have an expiration date, but preferable consumption. In other words, if the day indicated on the label is exceeded, the product can still be consumed. "At that point, the food is not in bad shape, but its qualities begin to change and they are not what the manufacturer likes," explained the food technologist and director of the SAIA consultancy, Lluís Riera, in this article.
However, these products also deteriorate over time. For this reason, as the days progress, it is key to check that the appearance, smell and flavor are not altered. In some cases, however, it can be hard to tell if something is wrong or not. An example is the one that Mario Sánchez, also a food technologist, has posted, who on his Twitter has published an image of a jar of lentils blackened on the surface. And he would ask the question: "Lentils in poor condition?"
"Well no!" The expert responded immediately. According to Sánchez, the fact that the lentils look like this is because the liquid that covers them (known as aquafaba) has not reached the top of the container. "It has turned blackish because the food has oxidized," he clarified. But although the legumes look dark and unappetizing, eating them "does not pose a health risk" (as long as the jar is unopened, because once the container has been handled things change).
To know if the canned legumes are in good condition, it is best to check that when you open them the lid makes a kind of "pop", which means that the vacuum is well done and therefore the food is well preserved. Once the container is opened, the technologist recommends consuming it within a maximum of three days.
To prevent the product from oxidizing, which, as explained, does not mean that it is in poor condition, some manufacturers use the EDTA additive in canned legumes. "It is completely safe, and it is in charge of sequestering metallic ions responsible for this unappetizing color change," concludes Sánchez.