Most people I know use Vegemite for the culture, this is because it is yeast based, so on that basis you can use anything with a yeast base. So you will need to get some micro worms from someone within your club to start the culture, then add the microworms to the bread and vegemite and sit back and wait. As for going off, this is anyones guess, I have had 2 cultures sitting along side each other, one goes off and the other can carry on for months, You will know when they go off because they smell even worse (If that is possible)