Most contamination comes from the air and from your hands. A still-air box (SAB) is a clear box with two arm holes that gives you a calm pocket of air to work in, so floating dust and spores settle out before you open a jar or plate. It is not a laminar flow hood, but it is the cheapest big improvement you can make.
What you need
- A still-air box
- Sterile gloves and alcohol wipes
- Sterile scalpels for agar work
- Your cultures: agar plates, grain jars or liquid culture
Setting up
- Pick a calm room. Close windows, switch off fans and air conditioning and avoid a room with pets. Wait for the room to settle.
- Wipe the box. Spray or wipe the inside with 70 per cent isopropyl alcohol, including the arm holes.
- Load everything first. Put in all items you need, wiped with alcohol, before you start. Opening the lid mid-job ruins the still air.
- Wait. Leave the box closed for 10 to 15 minutes so dust settles.
- Prepare yourself. Tie hair back, wear a clean top, wash your hands and wear fresh gloves. Wipe your gloved hands with alcohol.
Working inside
- Move your arms in and out of the holes slowly. Fast movement creates exactly the air currents you are trying to avoid.
- Open containers only as far as you need, for as little time as you can, and keep the opening facing sideways rather than up.
- Do not talk or breathe directly over open containers.
- Close and seal every container before taking it out of the box.
Why contamination still happens
If cultures still get contaminated, usual causes are: not waiting for the dust to settle, moving too fast, leaving containers open for too long, skipping gloves, or starting from material that was already contaminated. Track which batches go wrong and change one thing at a time.
Practise with malt extract agar plates where contamination is easy to see, then move on to grain. See the full sterile equipment range, and read how liquid culture, grain spawn and agar fit together.
Our kits, cultures and supplies are intended for legal species such as gourmet and medicinal mushrooms. Growing mushrooms that contain psilocybin is illegal in the UK. 18+ only.
