We moved house a few years ago and I used a similar product quite a lot to improve the back garden prior to re-designing it. I don`t think it was sterilised because there was a strong aroma when the bags were opened but from what little knowledge I have about industrial composting, I think steam is used to provide heat in the process. It was a quick relatively cheap way to create reasonable growing conditions for a lawn and ornamental beds. I mixed it 50/50 with soil conditioner (another cheap compost product), and you couldn`t really tell much difference between them. I don`t think there will be much in the way of NPK in these materials but I was happy with the results. We get a variety of fungi appearing but I think that would be quite normal for any organic based medium. It would be interesting to learn a little more about the manufacturing techniques to see if anything undesirable is added. There seems to be quite a demand for any kind of organic waste materials for industrial composting these days, I can think of 2 large scale operations near us, one is run by the local council and the other is private. I think these methods need to be carefully watched but if done correctly could be beneficial to gardeners and growers alike.
Pete;-)