Except as provided in Regulation .02C of this chapter, critical items, transfer forceps, and soaking receptacles shall be placed on a steel tray or rack in the center of an autoclave or heat sterilizer, separating instruments and keeping them away from the walls of the unit, and shall be sterilized according to manufacturer specifications or by: Autoclave at the temperatures listed for the following minimum time periods after completing a heat-up period: 15—20 minutes at 121°C (250°F), 15 psi (pounds per square inch) for unpackaged instruments; and 30 minutes at 121°C (250°F), 15 psi (pounds per square inch) for packaged instruments; or Dry heat, at the temperatures listed for the following minimum time periods after completing a heat-up period: 170°C (340°F) for 1 hour; and 160°C (320°F) for 2 hours. Sterile critical items, transfer forceps, and soaking receptacles shall be stored in sterile covered containers until used. Transfer forceps and holding containers shall be cleaned and sterilized daily or more frequently if visibly contaminated. Unused instruments in containers and containers that have been opened shall be resterilized after a 24-hour period. Dry heat ovens and autoclaves shall be of a type registered with the federal Food and Drug Administration (FDA) and shall be cleaned, used, and maintained according to manufacturers' instructions. Sterilizers shall have visible temperature and time indicators. Chemical indicators using color change materials shall be used on or in each package to assure that each package or container has been processed through the sterilization cycle. Biological indicators shall be used no less than once a month according to manufacturers’ instructions to assure that the sterilizer is functioning properly.