All biomedical waste to be autoclaved must first be placed in an approved and labeled autoclave bag. Sharps such as needles and scalpels must be placed in an approved, labeled, edged sharps container before being sterilized. Do not place sharp pipettes or broken glass in the bag. This waste should be placed in boxes or buckets and autoclaved, or sterilized using a liquid sterilant such as 10% sodium hypochlorite. Biomedical waste to be sterilized in an autoclave must have an indicator that proves the waste has been autoclaved before it can be disposed of. Many autoclave bags come with an indicator that reads "AUTOCLAVED" when the sterilization cycle is complete. Indicators must be applied to boxes and barrels before they are autoclaved and placed in the bin. Potentially infectious waste must be labeled "biohazard" and have a biohazard label affixed to the container. When sterilizing non-hazardous materials such as research animal essentials, culture media, and laboratory equipment in a sterile environment, unmarked plain containers are sufficient.
Before starting, approximately 50 ml – 100 ml of water should be placed in the autoclave bag to facilitate steam generation in the bag. If this water is naturally present in the load, there is no need to add additional water. Autoclave bags should be well wrapped to prevent spillage if they occur. However, if the tape is wrapped too tightly, steam pressure can build up inside the bag, causing it to rupture. Don't double your trash bags. Autoclave bags are designed to be permeable to steam, but a double bag will prevent the flow of steam through the bag. Do not overfill the bag or autoclave as poor steam flow may interfere with the sterilization process. It is best not to put the bag directly into the autoclave. They should be placed on stainless steel or polypropylene trays.
When autoclaving liquids, do not fill the container more than 75% full. This will ensure that the fluid has room to expand as it heats up. Because the use of steam to sterilize liquids can be problematic, it is best to use chemical agents to sterilize liquid waste if possible. If researchers choose to use steam to sterilize liquids, the container containing the liquid must be able to withstand autoclave conditions. Borosilicate glass or polypropylene containers can be used. Make sure to loosen the lid on the container to build up pressure during the process. During autoclaving, always place loose glassware and liquid containers into secondary containers. Wear thick, heat-resistant gloves, safety goggles, and a rubber apron when removing liquid from the autoclave. For liquid loads, the autoclave's venting cycle must be set very slowly. This gives the liquid time to cool down below 100°C, so it doesn't boil as the pressure decreases. After the run is complete, slowly open the door and back off until the steam has purged.
