Why is it important that the manufacturer have this?
Making bamboo fiber constitutes using chemicals to process the bamboo pulp into fiber. The process is similar to making rayon. Without outside quality control, there's really no way of knowing if the bamboo fibers are free of these chemicals, and/or that these factories are running a good company. Attaining an ISO 9000 certification in China is lengthy process, and if you choose to buy bamboo fabric made from another factory, you should make sure that they are certified.