The incident took place at John Cox Cold Stores and Distribution Services, trading as Midland Bacon Company on December 23 2009.
Wolverhampton Crown Court was told that Daniel Wilfred, aged 20, from Walsall, severed three fingers when his hand became trapped in a packaging machine.
Wilfred was walking through the firm's curing department when he saw bacon joint packs falling to the floor from the cutting unit. To prevent this, he leaned over the conveyor and put his left hand into the cutting unit.
Wilfred's hand became trapped between the machine and the cutting blades, resulting in the loss of three fingers up to the first joint.
After the hearing, Health and Safety Executive (HSE) inspector Eve-Marie Edwards said: "This incident was entirely preventable. The company had failed to prevent access to dangerous parts of the machinery which led directly to Mr Wilfred's injuries.
"Lessons need to be learned by employers, to ensure that potentially dangerous machinery is suitably guarded and that their workers are aware of the risks involved when working with these machines."
The firm, based at Leamore Lane, Bloxwich, pleaded guilty to contravening Regulation 11 of the Provision and Use of Work Equipment Regulations 1998. It was fined £30,000 and ordered to pay £31,000 costs.