Are Immigration and Customs in Melbourne strict?
Yes. Immigration and Customs officers in Australia in general are very strict. Make sure you’re not bringing in any prohibited items or undeclared regulated items. They often do thorough baggage inspection. Aside from using sniff dogs, they may also require you to open your bags and show the content to them.
Cigarettes and food served to you on your flight are PROHIBITED.
Most food items must also be declared.
To check whether or not the item you’re bringing with you is allowed, visit this page: Australian Border Force.