A show like MasterChef Australia: Back To Win is a major production with huge amounts of food being prepared, although not all of it is consumed on set.

Judge Melissa Leong has explained what happens to the leftover ingredients and food after challenges wrap up, saying sustainability and a low waste policy is a big priority for the Channel 10 show.

With a full-time sustainability officer working on the show, Melissa said some food is given to food rescue group Second Bite, which then redistributes it to charities and not-for-profit organisations, while the rest is put through a closed-loop organic system.