Contamination is typically described as, any foreign mold or bacteria growing on your substrate, grains or growing medias. Proper sterilization and sterile techniques are crucial for growing your own mushrooms and preventing contamination. Mushroom substrates are highly nutritious and moist. This is not only a great food source for mushroom spores and mushroom mycelium, but also for a vast number of other fungus and bacteria. It is critical for successful mushroom cultivation, that the only specimen introduced to the spawn or substrates, is the intended culture or spores. Open air inoculation or sloppy inoculation procedures are far more likely to contaminate. Sourcing your cultures or spores from reputable and experienced vendors puts the newcomers chances of success much higher.
Please do not let this article deter you from trying to grow your own mushrooms, trying a gifted spore syringe, making your own spore syringes or tinkering around with the hobby. I encourage long shots and attempting things without expensive equipment. Do not expect high success rates with "low tek" procedures, but please, play around with it, have fun and learn!
Fungal contaminates are caused by foreign mold spores dropping or being transferred to your growing medias. The most common fungal contaminate is a green mold called Trichoderma. Trichoderma is present in all soils and found commonly throughout the planet. IT IS EVERYWHERE! This is why it is hard to combat. Trichoderma is very aggressive and opportunistic. Although it is a major pain for mushroom cultivators, lets not give it too much hate. The ability of several Trichoderma species to form mutualistic endophytic relationships with several plant species is a very necessary job for ecology and plant health. Without Trichoderma we would have a unbalanced eco-system! Let just do our best to use proper sterilization and inoculation techniques to keep it where it belongs. OUTSIDE of the grow room and laboratory! Trichoderma will start off as a fluffy white mycelium. It takes some experience and a trained eye to spot it from normal healthy mushroom mycelium. Trichoderma mycelium will grow out and then produce spores without producing visible mushrooms! This is a very fast process. Once the mold has sporulated (made spores) it is likely to spread through the entire substrate. This will usually overgrow your healthy mushroom mycelium and prevent them from fruiting! Trichoderma spores are microscopic. When you can visually see the green mass, this means there are hundreds of thousands of spores. They can float in the air and contaminate other parts of your grow or laboratory. This is essential to keep out of your grow space and dispose of immediately. Always wear a respirator and gloves when dealing with contaminates. Fungal contaminates can produce mycotoxins that can be hazardous to human health.
Bacterial contaminates are typically caused by improper moisture contents of the media and improper sterile techniques during inoculation. Hyper-hydration slows the growth of healthy mycelium due to over saturation, it is then susceptible and ideal for bacterial growth. Avoid touching or breathing directly over grow mediums. Bacteria are usually yellow blobs or oozy gooey masses, and smell sour or fermented. They will cause stalled and irregular growth on grains and substrates.
There are some non-contaminate irregularities that can occur. They may alarm you but are harmless. For instance, blue bruising on psilocybin mushrooms and the mycelium is common. This will be a blue green tinting on the mycelium or mushrooms. This is typically caused by pinching or pushing on the substrate or mushroom. Transitioning from wet to dry in the grow environment can also cause bruising of the mycelium and mushrooms. Light bruising is normal and nothing to worry about. Metabolites are commonly mistaken for bacteria. Metabolites are excess polysaccharides, proteins, and peptides, terpenes, phenolic compounds, polyunsaturated fatty acids, carbohydrates and lipids created by the mycelium. Commonly called "mycelium piss". Throughout the myco community, they are harmless to the mushrooms and mycelium, they usually arise when moisture contents and humidity are slightly above desired levels. A third common question I get is about a "thick white fuzz around the bottom of the stems". This is from high co2 levels in the grow chamber, bag or environment. Commonly called "fuzzy feet" this is a sign you need to up you fresh air exchange (FAE) in the growing room or environment. Although the fuzz will not go away, the mushrooms will begin to develop and grow better. The white fuzz (just thick mycelium) is fine for consumption.
"When in doubt throw it out" is a safe saying. Holding on to jars or substrates that are contaminated or suspected of contamination is a bad idea. This can affect future projects and is tough to eradicate once its established in a grow room or laboratory. Be sure to clean the entire grow room or lab with diluted bleach solution before attempting to try another project.
Contamination can mean ANY foreign growth besides the desired specimen. It is not limited to molds and bacteria! If I am trying to grow Psilocybin Cubensis (Magic Mushrooms) and a spore from Pleurotus Ostreatus ( Oyster Mushrooms) lands on my growing media, it IS a contaminate. If I am trying to grow an isolated culture of Golden Teacher and a spore of Cambodian lands on the petri dish, it IS contaminated. If I am trying to grow an isolated culture of Golden Teacher and a spore of Golden Teacher lands on my petri dish, IT IS CONTAMINATED!!! This is why I highly recommend having your grow and laboratory spaces separate. I see posts on Instagram daily of cultivators showing off their harvest in front of their laminar flow hoods. Although it makes for a nice looking, seemingly impressive video, this is the worst place to bring fruiting, sporulating bodies. Making my skin crawl and shaking my head I resist commenting on their post.... They are exposing CONTAMINATES directly in the clean work environment!
A robots interpretation of "Mushroom Tidal Wave of Spores and Trash"