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Vol. 12 No. 2 - April 2006

Food Colours: Concern Regarding Their Safety and Toxicity

By: V.P. Kapoor

Presently, there is global trend towards the more usage of natural colours in food, pharmaceutical and personal care industries. Much awareness is created amongst consumers regarding the natural products and adopting more natural way of life. Now days, people prefer natural food, herbal medicines, natural curing practices and even biological farming without using synthetic fertilizers and pesticides. All this happened due to excessive use of synthetic chemicals/colours/derived products in the last one and half century which production and application cause human health hazard, environmental pollution and disturbing our eco-system. Due to adverse effect of synthetic dyes, all countries have made strict regulations about the permitted colours to be used as food additives. Most of the countries have prohibited the use of several synthetic dyes as food colouring agents and permitted a limited number of synthetic colours under specified maximum limits. The number of permissible colours vaired to some extent depending upon particular country. Apart from edible food colours, strict measures have been enforced for the use safe dyes for colouring textile and consumer goods. For example, Germany and Netherlands have imposed ban on the use of specific synthetic dyes for textile dyeing. India has also banned the use of 70-odd azo-dyes for colouring textile and other consumer goods and 118 chemicals have been put up in Red-List.

We need colour in food because all the senses contribute to the experience of eating. The impression food makes on us is a melange of sensations, and colour and surface appearance are amongst the most important. Many of the great experience in life involve a mix of sensation and eating is one of the original multimedia experiences. Addition of a suitable colour enhanced the appearance of fresh and process foods. In some cuisines, colour has played a more important part than others; for example saffron-coloured rice and lurid red of tandoori chicken.

Permitted Natural Colours

In India, Rule 26 of The Prevention of Food Adulteration Act, 1954 (PFA) and The Prevention of Food Adulteration Rules, 1955 & 1999 permit following colours whether isolated from natural sources or produced synthetically in food items:

a) Beta-carotene;

b) Beta-apo-8' carotenal;

c) Methylester of Beta-apo-8, carotenoic acid;

d) Ethylester of Betaapo-8' carotenoic acid;

e) Canthaxanthin;

f) Chlorophyll;

g) Riboflavin (Lactoflavin);

h) Caramel;

i) Annatto;

j) Saffron;

k) Curcumin (or temetic)

In the preparation of annatto colour in oil, any permitted vegetable oil may be used either singly or in combination and name of the oil or sils should be mentioned on the label.

Rule 27 of the PFA prohibits the addition of inorganic matters and pigments in any article of food.

Permitted Synthetic Colours

According to the Rule 28 of Indian PFA, following synthetic colours shall be used in food:

Rule 29 specified the food item in which these synthetic colours are permitted. These include ice-cream, frozen dessert, flavored milk, yoghurt, biscuits, peas, strawberries, cherries, custard powders, ice-candy etc.

Maximum limit of the permitted colour (Rule 30) shall not exceed 100 or 200 ppm of the final food or beverage for consumption. The colours should be pure and free from any harmful impurities (Rule 31)

International Status

Natural colours are widely permitted throughout world but there is no universally accepted definition of colouring matter. Some countries exclude the species from their list which have both flavouring and colouring effect. The species viz. turmeric, paprika, saffron, sandalwood oil etc. which have a secondary coloring effect are not classified as colours but declared as ingredients in the normal way. The list of permitted natural food colours in US and EU is bigger than Indian list. Apart from all 11 sources mentioned in Indian PFR, it includes vegetable carbon, copper complexes of chlorophyll and chlorophyllins, paprika extracts, lycopene, lutein, beetroot red, anthocyanins, cochineal, camine, cottonseed flour etc.

As regards to synthetic permitted colours, legislations of different countries differ to some extent on particular colours. Some synthetic colours are permitted in one country but banned in others. For example, Tartrazine (FD&C Yellow No. 5) is banned in Norway and Austria; Sunset Yellow FCF (Orange Yellow S) is banned in Norway; Yellow 7G is banned in Australia and USA; Ponceau; 4R (FD&C No. 4) is banned in USA and Norway; Erythrosine (FD&C Red No. 3) is banned in Norway; Brilliant Blue FCF (FD&C Blue dye No. 1) is banned in Belgium, France, Germany, Switzerland, Sweden, Austria and Norway; Indigotine-Indigo carmine (FD&C Blue No. 2) is banned in Norway; Green S is banned in Sweden, USA and Norway; Red 2G is banned in Australia and many other countries except U.K.; Vegetable carbon is banned in USA, Brown HT (Chocolate) is banned in Denmark, Belgium, France, Germany, Switzerland, Sweden, Austria, USA and Norway. As aregard to natural colours, Amaranth; FD&C No. 3, derived from the small herbaceous plant Amaranth is banned in USA, Russia, Austria and Norway. Similarly, some countries have banned the use of Paprica extract (Capsanthin & Capsorubin).

Colouring ingredients include natural colours, derived primary from vegetable sources; inorganic pigment; combination of organic and metallic compounds (lakes) and synthetic colours. These ^areused in processed food, sausage casting, baked goods, candies, ice cream, dairy products, sugar confectionary, flour confectionary, frozen products, gelatine desserts, dry-mixes, carbonated and other drinks. The principal natural colours, most of which, in refined form, are used as additives, are the green pigment chlorophyll, carotenoids, flavonoids, anthocyanins, betalains & betanins, anthraquinones, diarylmethane. At international level, the following natural colours are produced by numerous companies and available in market.

• Annatto (Yellow/Orange);

• Carotene (Orange);

• Beetroot (Pink/blue/red);

• Chlorophyll (Green);

• Beta Carotene (Yellow/Orange)

• Chlorophyllin (Green);

• Capsanthin (Red/Orange);

• Curcumin (Yellow);

• Carmine (Red);

• Lycopene (Reddish orange);

• Carminic Acid (Orange/Red);

• Lutein (Yellow);

• Anthocynin (Red/Purple);

• Vegetable carbon (Black)

• Toxicity Of Food Colours

The use of certain food colours has been banned on their toxicity observations on experimental animals. The use of non-permitted colours and excess of permitted colours generally cause adverse effects on human health. Some of the common after effects of prolonged use of synthetic colours cause hyper acidity, thyroid tumors, urticaria (hives) dermatitis, asthma, nasal congestion, allergies, abdominal pain, nausea, eczema, liver and kidney damage and cancer. For example, Auramine was found to cause dysfunction of liver and kidney; Rhodomine B was shown to cause retardation of growth and degenerative changes in liver in kidney; Malachite green caused decrease in appetite, growth rate and fertility rate; Yellow G provoked asthma; Allura red caused cancer in mice. In view of above, list of permitted food colours in different countries has some exceptions depending upon the recommendation of their food & Drug Authority Regulations.

Natural Colours as Health Cure

Besides colouring food, several natural dyes posses bioactive properties and have been used as therapeutic agents and as diagnostic tools. Some of the dyes have been reported for following curative effects; analgesics, antibacterial, antifungal, antileprotic, antiviral and anti-inflammatory. Turmeric has been reported as a digestive aid and treatment of carminative and stomach disorder. It has also been found as potential biomolecule for the treatment of cancer. Presently, there has been much interest in carotenoids, especially betacarotene (carrots, mango, papaya etc.) which besides natural orange pigment is converted in body to vitamin A and has antioxidant powers. Similarly, there is trend towards the use of anthocyanins (red grapes, red cabbage, elderberries, sweet potatoes etc.) and betacyanins (red potatoes, beet, amaranth etc.), which contribute positive health effect. There is lot of scope to introduce alternative sources of natural food colours but according to legislation, there exit a need for their extensive safety evaluation study through systematic pharmacological and clinical trials.

Conclusion

In India, only reputed companies, hotels, bakery, confectionaries and sweet-shops use the permitted colours in safe limits whereas its status at small or rural level is highly unsatisfactory. According to some reports, generally non-permitted colours are being used in the preparation of sweets, confectionery, bakery, ice-cream and other food items at local level especially at rural areas. The use of non-permitted colours and excess of permitted colours cause adverse effects on human and animals beings. There is an urgent need to undertake the issue at national level and create awareness in public for the safe use of edible colours.

Dr. V.P. Kapoor is Emeritus Scientist at the National Botanical Research Institute (NBRI), Lucknow, India

This article has been reproduced from the archives of EnviroNews - Newsletter of ISEB India.