NT to WA (Victoria Highway). There is bio security checkpoint on the border just before coming crossing into WA. Basically all frest fruit and vegetables and honey will be taken from you. For more details, here's the website WA Quarantine Checkpoint. There is a good supermarket in Kununurra where you can stock up again.
WA to SA (Nullabor). Leaving WA and crossing the Nullarbor, approaching Ceduna there is a biosecurity checkpoint and again, nearly all fresh fruit and vegetables will be taken from you. For more details, here's the website SA Quarantine check point