A food additive is almost exactly what it sounds like: it is a substance that is added to food in order to preserve its flavour, enhance its taste, or improve its appearance. Simple, natural food additives include salt and vinegar, such as salting meats to preserve them or pickling peppers with vinegar.
However, starting in the second half of the 20th century, food additives became more complicated. Instead of natural additives that had been used for centuries, laboratories began creating synthetic additives – some an off-shoot of natural products, some completely artificial. These new additives include food dyes and artificial sweeteners, along with a host of other additives and preservatives.