Basically, when the wort goes into the cube at near boiling temps, it's pasteurized. The owner of one of the largest homebrew shops in Australia sells premade wort that's made basically the same way. He showed us his warehouse, with hundreds of 20L containers of various types of wort. I was incredulous, but he told me it stays good for months like that. Tried a beer made with it and damn, it was good!
Wow, that is crazy!