The morbidly obese contestants on "The Biggest Loser" -- some of whom are close to death -- will be pushed to the limit by a new trainer who is NOT certified in California ... TMZ has learned.
We've learned Sandy Krum -- who's been on the show since 2007 -- got the boot before Season 15 began taping this summer. He's been replaced by a young gun named Ryan Applegate.
Sources connected with the "Biggest Loser" tell us past contestants and several staff members on the show are extremely upset that Applegate hasn't passed the stringent certification test -- a test that is not required by law but one that many trainers take because it cements their qualifications.
Quick reminder, these aren't your average Joes who are just a tad out of shape ... they're morbidly overweight people -- some of whom tip the scales at more than 500 lbs -- many of whom have extremely high blood pressure and suffer from diabetes.
A rep for the show's production company tells us, "The health and safety of our contestants is our #1 priority and the show is confident that the team of professionals they have hired to work with the contestants are qualified to do so."