Aquatic bacteria were isolated from the hands of working staffs by an adapted culture protocol. When the sample solution obtained by the "glove juice method" was incubated for 3 days at room temperature, viable cell counts increased up to 10(5)-fold, and the majority of the isolated colonies were shown to be Gram-negative aquatic bacteria, which carry the risk of contaminating water. Using R2A medium, coagulase-negative staphylococci were the dominant microbes immediately after recovery from the hands. Here it was revealed that bacteria of the phylum Proteobacteria isolated from the hand can be the causative bacteria of aqueous contamination. This modification in the GJ method may be useful as an effective training protocol to demonstrate the importance of hand hygiene and clean operation for aseptic manufacturing.