Kumaran Bose, an employee with Kettleby Foods for 12 years, has been backed by his Bakers, Food and Allied Workers Union (BFAWU) this week over his whistle-blowing.
"What his managers particularly disliked was his brave decision to stand up for his rights and refuse to accept that he and his fellow workers should be treated so appallingly," BFAWU regional organiser George Atwall said.
The Leicester-based firm owned by Samworth Brothers is at the centre of a scandal in which companies have reacted to the introduction of the higher minimum wage in the UK from April 1 this year by cutting workers' terms and conditions.
The strict rules are set to be highlighted in a television expose by Channel 4's investigative 'Dispatches' programme, which will be broadcast next week.
"I was the voice of the union, they set me up as an example. This is what will happen to you [if you join]. I feel I've been dismissed for union activities," Bose told The Times.
Bose and union officials say that in some cases workers could be denied up to 2,000 pounds a year in wages.
An employee working from Friday to Sunday, they say, would lose 27 pounds per week simply by being docked pay for taking an hour's break each day.
"Kumaran Bose was dismissed for two reasons and neither of them have anything to do with his union activity. As he has lodged an appeal and therefore the process is continuing it would be unfair on Mr Bose to make any further comment," a spokesperson for Samworth said.
"We are investing more than 5 million pounds extra in the pay bill every year for the next three years to support our recent pay review, a process that we launched more than 18 months before the national living wage was announced. The vast majority of staff are seeing a pay increase as a result of these changes," she added.
This will rise to 9 pounds an hour by 2019 in what the UK government has branded as the 'National Living Wage', as opposed to the minimum wage of the past.