we've been in and out of oz and we never declared any of our grocery stuffs that are commercially packed... well maybe except canned goods. if wala sa list na nakalagay sa prohibited items ng passenger card hindi na namin dinedeclare.
My wife brought lechon cebu packed in a tupperware as pasalubong. She declared it along with other groceries just ot be safe pero yung lechon lang talaga ang hindi pinayagan.
Ofcourse for first timers its alright to be worried and declare everything. Better safe than sorry syempre. Suggestion ko lang para iwas stress, lahat ng plano nyo ideclare na items, put it in one bag or luggage para kapag inispect, hindi nyo na bubuksan at maghahagilap sa lahat ng maleta.