Bakkavor Foods, an international food manufacturer, has been fined £20,000 - the maximum magistrates were able to impose - and ordered to pay £12,484 in costs after a production worker lost the tip of a finger.
Sushila Patel, 58, had the top of a middle finger sliced off by an unguarded dough-proving machine at a pizza factory in Harrow when she was asked to pick up dough balls being discarded from the faulty machine. She was treated at the Royal Free Hospital, and her middle finger is now shorter and causes pain and numbness.
The company was prosecuted by the Health and Safety Executive (HSE) after safety failings were identified at its factory following the incident on 22 August, 2012.
Westminster Magistrates heard that Mrs Patel had started work on the late shift in a bakery at the premises in Christchurch Avenue, Harrow. As line leader, she made technical and quality control checks and covered for staff absences.
During her shift, she was asked to pick up dough balls that kept dropping out of the prover machine because of an on-going fault. A guard on the machine, which was normally locked, was wide open and at one stage she had to reach inside to pick up the fallen dough balls.
As she did this, her right middle finger became caught between a moving chain and a sprocket, badly slicing the tip. The HSE found that a lockable guard on the machine had been left open, giving no protection to employees using the machine from coming into contact with dangerous moving parts.
Bakkavor Foods of West Marsh Road, Spalding, Lincolnshire, admitted a breach of the Provision and Use of Work Equipment Regulations 1998.
After the hearing, HSE Inspector Charles Linfoot said: "The fact that a lockable guard was removed highlights poor supervision of staff. The incident could have been prevented had the company rectified the machine fault and ensured guarding was effective at all times.
"HSE has been dealing with Bakkavor Foods Ltd regarding management failings in safety in recent years, and has dealt with the company over similar machinery guarding issues at another site.
"Food production has one of the worst safety records within the manufacturing sector. Companies must ensure that machinery is adequately guarded at all times to ensure the risk of contact with moving machinery is minimised."