Am I understanding contamination correctly?

[u/Rilkespawn]

On this sub I see many questions seeking clarification of contamination versus bruising. Frequently I see photos during the stages of spawning to bulk and fruiting. My question is where is this contamination coming from? If the substrate has no nutrients, and the grains were fully colonized before adding them to the substrate, then it must mean one of the following is true:

—contamination entered during the inoculation and colonization stage and simply didn’t show up until a few weeks later

—the grains were not fully colonized before moving to the spawn to bulk stage, thus allowing bacteria to feed on the grain nutrients still existing from colonization

—random bacteria was preexisting somewhere in the setup prior to spawning to bulk and the cleaning step with alcohol wasn’t thorough enough.

What other potential avenues of contamination am I not thinking of?

[u/shroomscout]

—contamination entered during the inoculation and colonization stage and simply didn’t show up until a few weeks later

This is perhaps the most common issue. Contam molds and some bacteria look like "mycelium" during the colonization stage of your spawn grain. They don't appear as contam until much later.

—the grains were not fully colonized before moving to the spawn to bulk stage, thus allowing bacteria to feed on the grain nutrients still existing from colonization

This is probably the second most common issue, especially with impatient beginners! Healthy, fully colonized grain is resistant (note resistant, not invincible) to contamination.

 My question is where is this contamination coming from?

I think you already got it; the two examples above are where it likely comes from.

Contamination is present in every single room in our house, in every breath we take. Unfiltered/unsterilized air is filled with contam spores. Any hydrated grain (of any kind, not just mycology-related) will contaminate when exposed to open air. Ever left some dishes unwashed for a few days, or a tea bag left in a puddle of moldy water?

Our goal is just to reduce this as much as possible. The easiest ways to do that are:

1. Start with a contam-free syringe. This is easier with LC than with spores, but even the best vendors will eventually sell a contaminated syringe on accident. You can test on agar first before inoculation.
2. Make sure you have good filters for gas exchange. Micropore tape barely cuts it, so double up or use proper synthetic filter discs.
3. Use a Still Air Box or flowhood when inoculating, and wipe everything with 70% ISO before use.
4. Let your grain colonized 100% before spawning to bulk.
5. Use community-proven coco coir (some brands actually PUT trich in their coco coir before selling as an anti-fungal measure).

That's it. Even if you do everything 100% correctly, there is always a chance the air in your grow space will contain a super strong dose of contam, or a hyper-aggressive trich, and will get contaminated.

Professional grow-operations for edible mushrooms also eventually get contamination, and they take WAY more steps for sterility than we do.

If you keep getting contam, then it's one of those 5 issues.

[u/AncientSpores]

I don't know friend, in my opinion, and I'm not a mycologist or a pro and 100% not to start an argument as it's just an opinion based on my own observations, testing and results, that 100% colonized grain can still get contamination. I've had more than one cake get trich in the 3 or 4th flush, almost 3 months after sending them. That's a long time for a mold spore to sit idle.

There are two common statements in our hobby "fully colonized spawn cannot get trich" and "once you have trich it will take over the entire grow". The latter we've all observed before. But if fully colonized spawn can't get trich, what's it feeding on and how is it taking over the entire tub?

Those two statements say the opposite things. The first says I can put a piece of contaminated cake into a fully colonized healthy cake and nothing with happen. The second says if put a piece of contaminated cake into a fully colonized healthy cake it will be consumed by trich.

I've sacrificed a cake of my strongest and aggressive ochra trying the latter. I took a some of contaminated cake out of my composter, just a swab of of the green/white growth from the top, where there is no nutrition, and swiped it on top of a fully cased, overlayed and colonized, pinning cake. In a week there was a patch of green along the swipe line.

So... I don't know, it just feels like with what I've seen that it is possible for colonized spawn to get contaminated.

[u/Rilkespawn → u/AncientSpores]

I almost added a fourth possibility to my list, which was “—random unaccounted for hoodoo.”

[u/AncientSpores → u/Rilkespawn]

100% RNG can be at play too friend.

FWIW I've never had a sealed unopened unmodified colonized tub get trich. I'm not a mass grower by any means but I've tried at least 30 tubs of various sizes that I do mostly neglect tek in unmodified 6/12 quarts with snap handle lids. It's only after I open them to harvest that I've had one go south. Under ideal conditions, mold spores like trich start to germinate in only 48 hours. Not 4-8 weeks. Our growing tubs are ideal conditions for both myc and trich. If the contam was present from day one it shouldn't take that long to go green. At least no every time.

Just my opinion and happy to be wrong.

[u/creept]

Yeah you’re mostly right. Contaminants showing up during fruiting are almost always coming from those sources. Also if you’re not doing a real pasteurization on your substrate (which bucket tek isn’t since you aren’t monitoring the temp) you’re introducing another possible route. 

But if you’re talking about contaminants showing up after 3 or 4 flushes like the other commenter, that’s not the same thing. That’s pretty normal and mostly unavoidable without a pressurized clean room or growing in front of laminar flow constantly. In that case the mycelium has consumed most of the nutrients from the spawn to create fruits, so it starts to weaken which opens the door for other contaminants to move in. It’s just the lifecycle in that case. 

[u/Rilkespawn → u/creept]

Thanks for the feedback. I’m just starting my first grow, so not even thinking to future multiple flushes. I appreciate the comment about bucket tek. That’s what I’m planning to do.

[u/creept → u/Rilkespawn]

Mostly it works fine and it’s what I use too. No problems. But when people are struggling with contamination over and over again it’s worth trying a true pasteurization just in case. But it’s more likely coming from other sources IMO. It takes a while to learn what normal spawn looks and smells like, so sometimes people are missing signs and going to bulk with compromised spawn. 

[u/ConfidenceLopsided32]

Contamination is almost always hiding inside the grain spawn. Trichoderma starts out white, just like the mycelium. It can be extremely hard to see. That's why so many people graduate to agar - it ensures the culture is clean when putting it into the grain, making contamination rates go down a ton.

Random bacteria also comes from the grain. Mycelium can become what is called bacterially embedded, where bacteria and mycelium grow at the same time along with each other. This means the mycelium will look pretty normal on grain, but later once you put it to sub, the bacteria will slowly start showing itself. When you grow on agar, it grows in 2D. This allows you to see bacterially embedded mycelium - it will look like a ring of clear snot or slime around the growing mycelium.

Contamination doesn't come from fruiting or the open air unless you used partially colonized grains or use a nutrient dense substrate. Since we use coir, contamination cannot come from the coir, because contamination requires some kind of nutrient to thrive. This is how thousands of people go straight to fruiting right after mixing the spawn and coir.

Contamination almost always comes from the grain because the grain contains the nutrients. This is why it is so important to only use clean, fully colonized grain spawn. If you use clean, fully colonized grain spawn, you could probably fruit in the trap house bathroom successfully.

If you use clean spawn, you don't need a casing layer.

If you use clean spawn you can go straight to fruiting.

If you use clean spawn you won't get contamination until after multiple flushes when the mycelium dies and releases the nutrients in the grain.

[u/Rilkespawn → u/ConfidenceLopsided32]

This is fantastic information and adds a big piece of understanding for me. Thanks!

[u/Nyx9000]

The air is full of contaminants. You’re breathing them in right now. You can’t remove all of these unless you’re working in a sterile lab, so minimizing air flow and maximizing cleanliness during inoculation can help avoid it. Grain is also a home for many contaminants like mold spores, so high-heat sterilization is important

Substrate like coir has no nutrients but things like mold don’t care about that little hassle. They will grow regardless

Think of it as a race: you want the thing you’re trying to grow to grow faster and to thrive better than the thing you don’t want to grow. Those things will probably grow given the right circumstance.

[u/Kylezar]

Not sure how relevant but my first time growing an easy grow Bluey Vuitton and they stalled after pinning, the shop said to monitor and check back but growth was minimal, they said it's contaminated on the inside (?) which I've not heard about before, it looks like it's still growing but very slowly.

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