Biological Laboratory Practices


  • Blending, Grinding, Sonicating, Lyophilizing: The greatest risk when using any of these techniques is the creation of aerosols. Blenders, grinders, sonicators, lyophilizers, etc. should be operated in a biosafety cabinet whenever possible. Safety blenders should be used. Safety blenders are designed to prevent leakage from the bottom of the blender jar and to withstand sterilization by autoclaving. They also provide a cooling jacket to avoid biological inactivation. Avoiding glass blender jars prevents breakage. If a glass jar must be used, it must be covered with a polypropylene jar to contain the glass in case of breakage. A towel moistened with disinfectant must be placed over the top of the blender while operating. This practice can be adapted to grinders and sonicators as well. Aerosols must be allowed to settle for five minutes before opening the blender jar (or grinder or sonicator container). Lyophilizer vacuum pump exhaust should be filtered through HEPA filters or vented into a biosafety cabinet. Polypropylene tubes should be used in place of glass ampoules for storing biohazardous material in liquid nitrogen. Ampoules can explode, causing eye injuries and exposure to the biohazardous material.


  • Centrifuging: The greatest risk with centrifuging is the creation of aerosols. Sealed tubes and safety cap buckets that seal with O-rings should be used. To avoid spills from broken tubes, the tubes, O-rings and buckets should be inspected for damage before each use. Leaks can be prevented by not overfilling centrifuge tubes. The outside of the tubes should be wiped with disinfectant after they are filled and sealed. Rotors and centrifuge tubes should be opened inside a biosafety cabinet. If a biosafety cabinet is not available, a minimum of 10 minutes settling time should be allowed before opening.
  • Emergency eyewash and safety showers . Be certain safety showers and emergency eyewash units are properly located, and maintained (reachable within 10 seconds). There should be no obstructions that might inhibit the use of this equipment.
  • Freezers and Refrigerators. These should be checked and cleaned out periodically to remove any broken ampules, tubes, etc. containing toxic or infectious material. Use rubber gloves during this cleaning. Label all biohazardous or toxic material stored in refrigerators or deep freezers (refer to Section 4.3.8 of the Biological Safety Manual). Discard old specimens or samples when no longer needed.