'Big Brother' Houseguest Cracks 'Rice Pudding' Joke About Asian Houseguest

The "Big Brother" house sounds a lot like a breeding ground for racism ... a white houseguest is in hot water after a racially charged joke about an Asian houseguest was caught on camera.

In a clip that was captured on the live feed inside the 'BB21' house this week, you hear Jack Matthews crack a joke about "rice pudding" in reference to Isabella Wang, who is Asian.

The other houseguests who heard the joke -- they are all white, BTW -- don't seem at all bothered by the clearly racist reference ... but people on social media are OUTRAGED.

In another clip captured on the live feed this week, you hear Jack talking about his "rice pudding" comment with another houseguest ... and it seems pretty clear Jack got a stern talking to from show producers. However, he says his joke was misconstrued ... he doesn't explain how.

It's another example of what people are calling rampant racism in the 'BB' house ... former houseguest Kemi Fakunle, who is black, says she was "disgusted by the behavior" in the house ... and some viewers have pointed out 3 minority houseguests got the boot on the same night.