Media Handling & Sterilization Once the medium is properly prepared, it is time to dispence the media into individual containers. After the Media is dispensed it is then sterilized. This section contains the procedures for dispensing and sterilizing the medium. Place the container of medium next to the dispensing unit. Place a stirrer in the medium and begin agitation. Place a dispensing hose into medium and begin pumping. Pump the solution back into the container until most of the air has left the hose. Using a graduated cylinder, calibrate the dispenser to deliver the amount required for each chamber. The amount of media per Star*Pac® chamber will vary depending on the type of Star*Pac® used and what type of plant material to be cultured. Typical amounts range from 10mL per chamber for a five(5)-chamber Star*Pac®, to 20mL per chamber for a two(2)-chamber Star*Pac®. After the dispenser is calibrated to deliver the correct amount, begin dispensing into the Star*Pac®. After the Star*Pacs® are filled, set upright in a tray. Star*Pacs® should be handled in units of five or ten. After the medium is despensed, fold the Star*Pac® in half, in units of five or ten. Place upright in a paper bag of the appropriate size. Six-pound or eight-pound bags are the most commonly used. Fold the top of the paper bag down twice and tape shut. Fold the top toward the seam, not away from it. This will prevent the seam from splitting after autoclaving. Autoclave tape is preferred, though any tape that can withstand autoclave conditions will work. Do not seal the Star*Pac® prior to autoclaving. Sealed bags will explode if autoclaved, due to the expansion of the air and liquid inside the Star*Pac®. Each paper bag should be labeled with the type of medium. Use a permanent marker so the writing will not fade after autoclaving. Place the paper bags into an autoclavable tray and place in the autoclave. The medium should be sterilized for a minimum of 20 minutes at 121°C and 1.2kg/sq cm (15 psi). Temperatures above 125°C can result in shrinkage or melting of the Star*Pac®. Sterilization times greater than 20 minutes may be required for large volumes of media. For large volumes, 25 to 30 minutes may be required for proper sterilization. For proper autoclave use, refer to the manufacturer's guidelines. Remove trays from the autoclave after the autoclave has finished the sterilization cycle. Shake trays when they are removed from the autoclave to disperse the gelling agent within the medium. This will promote uniform medium consistency. Store trays in the transfer room or the cleanest room available.