Britain’s Health and Safety Executive (HSE) conducted an investigation and found guarding that had been installed on the machine was inadequate
It also found safety improvements were necessary to a range of machines, including to prevent access to dangerous parts or repairs to existing safeguards.
The company was ordered by Southern Derbyshire Magistrates’ Court to pay £20,000 in damages and told to pay full costs of £7,680.
On 17 November 2009, Ellen Yardley, 37, from Derbyshire was working at Thortons’ Somercotes plant on a foil wrapping machine.
She attempted to clean the inside of the output chute which had become covered in caramel during a short break in production.
The cloth used to clean the chute became tangled in rotating parts which gripped the chocolates and her right hand was dragged into the machine.
Ms Yardley’s middle finger was fractured and cut, forcing her out of work for 10 weeks.
Thorntons pleaded guilty to breaching Regulation 11(1) of the Provision and Use of Work Equipment Regulations 1998 and Regulation 3(1)(a) of the Management of Health and Safety at Work Regulations 1999.
HSE inspector Stuart Parry said after the hearing: "Thorntons should never have allowed the machinery guarding to fall below the legal safety standards. It was effectively asking its employees to work on machines that put them at risk of injury.”
"It was entirely foreseeable that the inadequate guarding could lead to injury and even if Ms Yardley had not used a cloth, her hand could still have been drawn into the machine while cleaning it,” he said.
"If the company had carried out an adequate risk assessment of its machinery, its workers would not have been put at risk and in Ms Yardley’s case painfully injured," he continued.
Thorntons said in a statement: “Thorntons accepts the court’s decision regarding the fine imposed in relation to the two technical breaches.”
“Providing a safe workplace for our employees is a priority and we deeply regret that one of our colleagues was injured in this instance. We carried out a thorough review of our systems and procedures following this incident to ensure that such an accident cannot reoccur.”