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
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.
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withdrawn from use.
and synthetic colouring
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.
a specific colouring from your diet
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
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.