For a small but vehement section of the population, just the mention of coriander is enough to inspire pure revulsion – long before the herb has had the chance to infect any food.

Most people find coriander to have an agreeable, citrus flavour, but for this vocal minority it tastes more like soap.

Now the high-street sandwich shop Pret A Manger has come under fire from these coriandaphobes for its liberal use of the “devil’s herb”.

“Totally gone off @Pret. Coriander in everything,” tweeted one user. “Why do Pret insist in ruining a decent flatbread with coriander?” wrote another.

Neena Thomas, a 25-year-old graduate living in Nottingham, moved to the UK from Ireland. She was particularly excited, she says, to visit Pret A Manger. “They make good fresh sandwiches with interesting flavours. But every time I’ve been, all the ones I like the look of contain coriander. It’s hugely disappointing – I’m left with the bland options.”

We like using generous helpings of fresh herbs and we’re not looking to remove coriander from any of our products <p>Spokesman for Pret A Manger</p>

Thomas, who studied human genetics at university, has gone as far as to have her genome sequenced – and found she has the genetic mutation that scientists have identified as causing some to find the taste of coriander so obnoxious.

“For most people coriander tastes lemony and citrusy but for me it tastes like that smell you get when you’re washing up the dishes. Like old dishwater,” she said.

According to the Oxford Companion to Food the word “coriander” derives from the Greek word for bedbug, apparently because the smell of the herb “has been compared with the smell of bug-infested bedclothes”. Scientists have pinpointed the herb’s aroma to fat molecules called aldehydes – which are also found in soap and bug-type insects.

Pret, however, remains unrepentant. “We like using generous helpings of fresh herbs and we’re not looking to remove coriander from any of our products,” said a spokesman for the company.

Hannah Dolan, 32, a development chef for the chain insists the ingredient is only used in products when it “makes sense” – and points out that it is present in only five of the company’s 56 products.

“It’s in our Mexican chipotle flatbread and in our falafel because it is associated with Central American and Middle Eastern cuisine.”

Some Twitter users’ complaints are more specific. They say, for example, that the unwieldy, unchopped stalks make eating ungraceful.

“I feel like an animal eating at my desk; my colleagues have to turn away,” said one customer. But Dolan says the company will not budge: “All the flavour and the bounce of the ingredient is in the stalks.”