The agency (MHRA) require a supply of Biological Indicators (BI) for use in Fumigation Validation of Formaldehyde fumigations. The BI must consist of stainless steel spore disc, each disk is impregnated with a suspension of Bacillus atrophaeus (formerly Bacillus subtillis var globigii), (ATCC 9372) spores with a nominal population of ...