Burrell told BBC Sport he also faced prejudice within the England set-up, during a Test career that saw him win 15 caps after his debut in February 2014.
“I’ve had several traumatic experiences within England camp,” he said.
“Some discrimination and some just old-school mentality that’s really unacceptable.”
Racism had become normalised in dressing rooms, in Burrell’s experience.
“It’s something that has been dressed up as banter and that’s been the problem that I’ve personally suffered and seen,” said Burrell, who is of Jamaican descent.
“Over a period of time you just learn to believe that it’s the norm and that is fine and that it’s not malicious, but that’s nonsense.”
Burrell says he was eventually spurred to speak out after a team-mate at Newcastle referred to him as a “slave” and told him to put sun cream on his wrists and ankles “where your shackles were”.
The RFU said Burrell’s revelations had led to “a deeper look at the culture within the elite game and to the implementation of an action plan for the professional game”.
“The RFU has placed significant focus on inclusion and diversity in rugby union and a great deal of work undertaken both before and since Luther Burrell came forward and shared his experiences of racism and classism,” it added.
“We are continuing work with clubs and stakeholders in the professional game to strive for a culture of inclusivity but acknowledge this takes time and is an ongoing process.”
Every Prem and PWR club now has face-to-face education on building inclusive cultures, with its success monitored via individual reports and surveys.
All England players, including age-grade squads, are trained in being “active bystanders” to intervene and protect others from harmful behaviour.
“You should be so proud of what you have done,” Burrell’s mother Joyce told him as part of the BBC iPlayer documentary Luther Burrell – Rugby, Racism and Redemption.
“I know it has had this effect on you and finished your career, but in our eyes, you have done so well. We are so proud of you and to have you as a son.”
Burrell’s father Geoff died shortly after the filming of the documentary, and his sister died earlier this year.