If the food items are commercially packaged and if you declare them on your incoming passenger card (that is critically important), you will almost certainly be allowed to bring them into the country. Anything that is confiscated is immediately put into secure bins for destruction and is NEVER eaten by customs officers. They don't confiscate prohibited things just for the sake of it but to protect our environment.
http://www.daff.gov.au/aqis/travel/enter…
Note that the items listed are those that must be declared. It is not a list of prohibited items and many will be returned to you after inspection. Don't try sneaking anything in or the sniffer dogs will pick it up and then it WILL be confiscated and you'll be fined.
http://www.aqis.gov.au/icon32/asp/ex_cas… (the specific regulation relating to cakes and biscuits. It shows that even home cooked cakes and biscuits are OK if they don't have custard or dairy based fillings BUT, you must still declare them)