West Yorkshire Trading Standards said the dyes, which are banned for use in foodstuffs, and are used to stain microscope slides and detect leaks in drains, were found in Asian sweets.
The organisation told FoodManufacture.co.uk a Trading Standards officer initially spotted the problem in November last year after noticing the particularly lurid colour of sweets sold in an Asian bakery in Calderdale, West Yorkshire.
The sweets were traditional Asian confectionery, made with milk and sugar, and were not made by the shop, but by a nearby bakery, said a West Yorkshire Trading Standards spokesman.
Samples were tested and the presence of two dyes, Rhodamine B and Auaramine, was detected, he said. “We subsequently found another two manufacturers in West Yorkshire also using the Rhodamine B dye,” he added.
In a statement, West Yorkshire Trading Standards said Rhodamine “appears green in powder form but when added to water turns a vivid, fluorescent pink colour. It is not a permitted food colour and is considered to be potentially carcinogenic.
Used in sewage industry
“Rhodamine B is commonly used to stain slides in laboratories and is used in the sewage industry to test for leaks in drains.
“Auaramine appears yellow/orange in both powder and liquid forms. This is also commonly used to stain laboratory slides. It is not a permitted food colour and is also potentially carcinogenic.”
Authorities do not yet know how the dyes were originally obtained. However, the Trading Standards spokesman said it was possible they originated in Pakistan. “They are used widely, but illegally, in Pakistan.”
The situation is eerily reminiscent of the 2005 food scandal, in which illegal, cancer-causing dye Sudan 1 was discovered in the food chain. However, this latest scare is not thought to be nearly so widespread at this stage.
West Yorkshire Trading Standards believed use of the dyes had not spread beyond its catchment area, said the spokesman. “Based on the information uncovered so far, distribution tends to be between wholesalers and retailers in West Yorkshire."
The suppliers implicated also distributed products to local curry houses and specialist confectioners, he said.
Both dyes are banned in food and drink under the Food Additives, Flavourings, Enzymes and Extraction Solvents (England) Regulations 2013. Any business using them was committing an offence and faced prosecution, said the Trading Standards spokesman.
They become fluorescent under ultraviolet light, which could help businesses identify them, according to the Trading Standards statement.
“We advise anyone with concerns to contact their local Environmental Health or Trading Standards department or the Citizens Advice consumer helpline on 08454 040506,” said the spokesman.