Insiders say the Fairtrade fruit industry should brace itself for close media scrutiny following claims of worker abuse at a UK banana supplier.

The allegations came to light last week when a Polish worker at Pratt's Bananas in Luton claimed she miscarried after being denied rest and lighter duties. She is taking the company, which supplies Tesco and Waitrose with Fairtrade and conventional fruit, to a tribunal.

John Bowes, of Fairtrade importer AgroFair, said he was not surprised by the allegations. "When Fairtrade was relatively niche five years ago, it was accepted for what it was. Now it's going to come under increasing scrutiny and if there are abuses, it's right to expose them."

The industry should expect further claims of abuse by workers in the future, he added. However, the Fairtrade Foundation said that the real issue was working conditions in the UK, not Fairtrade itself. "We don't expect sales of accredited products to be affected," said a spokeswoman.

The Foundation has asked Pratt's to improve working conditions, but says it has no power to take further action because UK working conditions technically fall outside the scope of the Fairtrade mark. Pratt's just imports Fairtrade bananas and does not have to be accredited as a Fairtrade company.

Waitrose has concluded an emergency audit of the company and said it would take appropriate action once it had looked at the findings. It could not say whether that might include reviewing Pratt's contract.

The Gangmasters Licensing Authority was also taking a close interest in the case, although it said there was no evidence to suggest Pratt's labour provider, Response Personnel, was implicated.

Pratt's said it took the allegations very seriously and would retrain all supervisors immediately.