Contamination is the bane of mushroom cultivation - unwanted organisms that compete with or destroy your mushroom mycelium. Prevention through proper sterile technique is always better than trying to fix contamination after it appears.

Common Types

Molds:

• Trichoderma (green mold) - most common
• Penicillium (blue-green mold)
• Aspergillus (black mold)
• Cobweb mold (gray, wispy)

Bacteria:

• Bacillus (wet spot, sour smell)
• Pseudomonas (yellow/brown slime)

Prevention

Key prevention strategies:

• Proper sterilization of substrates
• Sterile inoculation technique
• Clean growing environment
• Quality spawn sources
• Appropriate moisture levels

Identification

Look for:

• Unusual colors (green, blue, black, yellow)
• Strange odors (sour, sweet, musty)
• Abnormal growth patterns
• Slimy or wet textures

Once contamination is visible, it’s usually too late to save the substrate. Focus efforts on prevention rather than treatment.