The demand for canned foods skyrocketed during the first World War. In order to feed millions of soldiers, there was a need for high-calorie, cheap food, which was also able to be transported efficiently. The first few foods that were canned for this use was beans, pork and bully beef. When the militaries realized that more morale-boosting foods were required, foods such as ravioli, pasta e fagioli and beef bourguignon were then introduced. Glass jars were originally used to preserve foods but presented many challenges. It was then that the cylindrical tin can was introduced, now known as just "cans". These were cheaper and faster to produce. Can openers were only invented 30 years after this.
There may be a chance of toxic substances migrating from the can to the contents. Substances like these include lead. One of the most common food canning processes involves storing the food in salt dissolved in water. Health problems may arise from the consumption of too much sodium, such as high blood pressure. Although many canned foods in modern times are available with low salt contents. A rare but very dangerous risk of consuming canned foods include ingesting C. botulinum spores, this causes an illness called Botulism. Botulism causes paralysis, which can spread to breathing muscles, in turn causing respiratory failure.