The recall of food linked to the Sudan I contamination has prompted questions about what additives are allowed in our diet.
Colours, preservatives and other agents which have been licensed by the European Union are represented by the letter E and a number. Some are natural, some artificial. They have been tested for safety and passed for use.
But restrictions may apply. The UK's Food Standards Agency (FSA) enforces strict limits on the levels of colourings allowed in food, and they are banned in some foods such as baby foods.
Still, colourings are controversial. Some say they are unnecessary and some which are licensed by the FSA have been linked to harmful side effects in a small number of people.
But the FSA says all licensed additives have undergone thorough testing and are safe for the general population. However, just as some people react to some everyday, natural foods, so they may react to certain additives.
"People who react to additives normally have asthma or other allergies already," said a spokesman. "We carry out work on additives to ensure that their presence in food does not compromise food safety."
There is no scientific evidence to link some additives with attention deficit hyperactivity disorder (ADHD), he added. Consumer rights magazine Which? says reactions to additives are rare but urges a clearer labelling system on foods.
The following are among the substances permitted in the UK - judged safe by the FSA - which have been linked to allergic reactions or hyperactivity in children, although these claims are contested.
What is it? A yellow food colouring made from azo dye.
Where is it used? A range of foods including soft drinks, sweets and sauces, although use has decreased in recent years.
SUNSET YELLOW (E110)
What is it? Another yellow food colouring, also known as FD&C Yellow No 6.
Where is it used? Soft drinks, sweets and sauces.
BRILLIANT BLUE FCF (E133)
What is it? A blue colouring made from azo dye, also known as FD&C Blue Dye No 1.
Where is it used? Often used with tartrazine to produce a shade of green in dairy products, sweets and drinks.
BRILLIANT BLACK BN (E151)
What is it? A black colouring made from azo dye.
Where is it used? Brown sauces and blackcurrant cake mixes.
BROWN HT (E155)
What is it? A brown colouring.
Where is it used? Chocolate cake mixes.
GREEN S (E142)
What is it? Green colouring.
Where is it used? In canned peas, mint jelly and sauce, packet bread crumbs and cake mixes.