Food Additives and Colours- Food colour

From its colour, we can often tell whether food is fresh or stale, of good or poor flavour, and whether it contains particular ingredients. Because colour is important to the consumer, colours are added to food to give an attractive appearance, when it has been lost during processing or storage, or to overcome natural colour variation to ensure a consistent product.

Food colour and flavour are closely associated. When we see a food we anticipate certain flavours. We learn to reject foods that are not coloured in a familiar way. How many of us would drink black milk even if it smelled and tasted right? We expect that a red apple will be sweet, a green plum will be sour and a brown icecream will have a chocolate flavour. Tests with testing panels showed, for example, that when children were asked to identify the flavours of red and yellow jellies, the majority identified the red jellies as strawberry flavoured and the yellow ones as lemon flavoured, regardless of the flavour actually present.

'Safe' colourings

The addition of colour to food is, for some people, an emotive issue, largely because colours are seen as cosmetic and because, from earliest times, colour was added to food sometimes to deceive the consumer as to the quality or identity of the food. Some of the colours used in food in earlier times, particularly during the nineteenth and early twentieth century, were toxic. More recently, some of the colours used are suspected of causing cancer in animals. The use of colour additives in food is controlled by law, and only those additives that are considered to be safe are permitted to be used. As more tests are performed and information becomes available the list of permitted colours may change. Some tests may cast doubt on safety and the colour should then be withdrawn from use.

Natural and synthetic colouring

Colouring that is added to food may come from natural sources or may be a synthetic product. Synthetic colours can be chemically identical to colours that occur naturally, or they may have no counterpart in nature, as with the widely used synthetic coal tar dyes. It is important to realize that there is nothing about a natural substance that makes it intrinsically more safe than a synthetic one. Figure 27 shows a list of food colourings permitted in Australia. Colours are often used in combination to produce a desired shade and this can be confusing if a person is trying to avoid a particular colouring: for example, a green cordial may be produced by using Green S or by combining tartrazine with Brilliant Blue FCF.

Eliminating a specific colouring from your diet

Tartrazine is a widely used yellow colouring, which has been associated with allergic reactions in some rare instances. Reactions have ranged from rashes and swelling to asthma and possibly even behavioural changes. If it is medically advised, diets that eliminate specific additives can be compiled. These diets should be maintained only under medical supervision, as prolonged exclusion of certain foods from the diet can lead to development of nutritional deficiencies. In Australia, tartrazine and other added food colouring can be identified by their code numbers (see Appendix A for additives and their numbers). For example, 'colours (102, 110, 133)' in the ingredient list means that the food contains tartrazine, sunset yellow FCF and brilliant blue FCE In the U.S.A., foods containing tartrazine (where it is known as FD&C Yellow No. 5) are required to list this colouring by name. Many drugs also contain colouring additives and this fact is sometimes overlooked when trying to avoid particular colourings.