Safe & Effective Work Practices
Before work is started:
- Remove all unnecessary equipment and supplies from the cabinet, clutter alters air flow. Check that air grilles are clear.
- Turn on blower before using to remove particulates in the cabinet. Wait at least five minutes.
- Wipe down surface of cabinet interior with disinfectant.
- Prepare a checklist of materials necessary for the activity. Place supplies and needed equipment in the BSC before beginning work to minimize the number of arm-movement disruptions across the air barrier of the cabinet. Only items required for the immediate work should be placed in the BSC.
- Place absorbent towels and decontaminating solution near the cabinet to facilitate quick clean up of spills.
- Wipe the exterior of supplies with a disinfectant, particularly containers removed from a water bath. Segregate items that will remain clean from the ones that may become contaminated.
- Wash hands and arms, wear appropriate protective equipment for the work being done and to prevent skin flora from contaminating your work.
- Adjust stool height so that your neck and face are above the sash opening.
While working in the cabinet:
- In order to prevent air disturbances that can breach the air barrier, never have more than one person at a time use a cabinet - even six-foot cabinets.
- Delay manipulation of materials for approximately one minute after placing the hands/arms inside the cabinet. Do not rest arms on the front grille. Raising arms slightly will lessen disruption of air flow.
- Work as far back in the cabinet as practical - at least four inches inside the front grill edge.
- Move arms slowly and limit arm movement in and out of cabinet.
- As a general rule of thumb, keep clean materials at least one foot away from aerosol-generating activities to minimize the potential for cross-contamination.The work flow should be from "clean (left) to contaminated or dirty (right) ". Limit the movement of "dirty" items over "clean" ones.
- Not pouring liquids will eliminate the need to flame bottlenecks. Remove media with vacuum and replace with serological pipettes.
After work is complete:
- Wipe down the surfaces of all containers and equipment with an appropriate disinfectant and remove from the cabinet.
- Leave blower on for several minutes with no activity so that any airborne contaminants will be purged from the work area.
- Wipe down the cabinet interior with disinfectant.
- Remove gloves and wash hands.
Tips to prevent contamination:
- Clean water baths frequently and/or treat water in bath.
- Clean the inside of incubators frequently, particularly the water tray. Use sterile water in the bottom of the incubator or water tray.
- Use HEPA filters on incubator CO2 and air intake lines. Replace regularly.
- Lab coat sleeves can introduce contaminants to biological safety cabinets and incubators. Use coats designated for working in the biological safety cabinet or tissue culture area, launder frequently. Use disposable sleeve guards if contamination has been a problem.
- Never pour media, remove with vacuum and replace with dispo pipettes.
- Do not leave flasks of waste media in cabinet, clean after every use.
- On a regular basis, decontaminate under the air grilles and wherever parts are removable. Media is commonly splattered on the front grille allowing fungus to grow undetected on the under surface of the grille. UV light will not reach this hideout.
- Decontaminate the surface of carts or trays used to transfer culture flasks between the incubator and the biological safety cabinet or microscope.
- Keep pipette aids cleaned, especially the nosepiece, and replace filters regularly.
- Clean and disinfect vacuum tubing.
- Keep the water in the incubator's water jacket full. If water levels in the jacket drop, the ceiling of the incubator will be cooler causing condensate to form. Water then drops onto shelves and cell culture containers.
- Check port plugs and septums for contamination in incubator interior; they may trap moisture and harbor fungi.
- Most contamination problems can be traced to incubators, water baths, or using poor aseptic technique. Don't be lulled into believing that the use of UV lights or flaming containers will keep you contamination free.