Contaminating bacteria are ubiquitous and are found on fingertips, bench tops, and in the air. It is important to avoid contaminating the experiment by keep surfaces clean and exposure of culture media to air minimal.

• 1. Opened media, culture and labware should be kept in a sterile Clean bench or Biosafety cabinet. Read Laminar flow hoods and chemical fume hood for standard practices.
• 2. Clean surfaces such as bench top with ethanol (70%). Pipet aid should also be cleaned with ethanol (70%).
• 3. Wear gloves and/or clean hands with ethanol (70%).
• 4. Sterilize all media, ddH₂O, and pipet tips etc. by autoclave or filtering (≤ 0.22 mm filter).
• 5. Avoid prolonged exposure of media, plates to air without cover.
• 6. Check for mycoplasma contamination.
• 7. Clean incubators with diluted bleach and then 70% ethonal. Removable shelves can be autoclaved.
• 8. Add an algicide to the humidification pans to prevent microbial growth.