Been watching the tv show "Border Security" and seen loads of people getting stopped for not declaring various food items etc.

Two things I tend to bring with me are these sachets of Nescafe coffee and a certain brand of Oatflake cookies / biscuits that I snack on (flour, sugar, oats etc)
Would these be fine to bring into the country (I assume I have to declare them)?

Also, I run a bit and would naturally bring my running shoes as a run around Darling Harbour would be something I would be looking at doing.
Did see something where someone had some mud / dirt on some shoes in their baggage and could this be problematic? Wouldn't want to risk by not declaring, getting pulled over etc and losing the shoes if possible.