A Root Cause Analysis of Bacterial Contamination in Spawn Production
This case study is shared by a Mycelia Academy expert and a member of our Myco-Vision research team – one of our trusted partners – reflecting on a real contamination event and the lessons it taught us about hygiene mentality.
Everything looks right: the autoclave ran its cycle, tools were flame-sterilized, inoculation happened under HEPA-filtered laminar flow. Gloves were on, bags were sealed, protocols followed to the letter.
And still… something goes wrong.
We’ve all seen it – a batch of fungal spawn that looks fine on day one, only to smell sour on day three. Mycelium weak or absent. Contamination creeping in where it shouldn’t.
In our case, it wasn’t a catastrophic failure. It was a subtle one. And because our monitoring system worked – we caught it early enough. This post unpacks what happened, how we traced it back, and why the real problem wasn’t a dramatic failure or a broken machine. It was a mindset that momentarily let its guard down.
The Symptom – A Sour Bacterial Smell
The signs were unmistakable. A few days into incubation, freshly inoculated bags began to show signs of contamination. Some emitted an unpleasant sour odor and there was increased condensation on the inside of the bags while the mycelial growth was weak, at best. These were clear signs of bacterial activity, flourishing in the warm, humid conditions meant to support fungal growth.
It was tempting to blame the handling during inoculation or assume a sterilization error. But swift investigations revealed no such issues. The real cause lay downstream in the production process.
Unpacking The Problem – Root Cause Analysis
To understand where the contamination came from, we mapped the entire spawn production process using a Root Cause Analysis (RCA) approach – a structured method for tracing underlying causes rather than treating surface symptoms. Every step – from autoclaving to inoculation to incubation – was reviewed in detail.
Sterilization and inoculation protocols were validated first. The autoclave cycles had held temperature for the required time. Bags were sealed properly. During inoculation, everything was handled under filtered laminar flow.
Next, we looked at the operator’s workflow – how people moved through the facility, what they touched, and when. That’s when we noticed that the sluices – transitional zones between the outside and the sterile room – deserved closer attention.
The Root Cause – A Breach In Mental Hygiene
Sluices are critical control points.
They’re designed as hygiene buffers – barriers between the outside world and the sterile workspace. But when their maintenance is neglected, they quietly become a risk.
This happened during the onboarding of new operators. Most routines were in place, but the cleaning of the sluices hadn’t yet been clearly assigned.
It was a simple case of shared responsibility becoming no one’s responsibility.
Once the bacterial pressure was high enough, some hitched a ride: they attached themselves on the clothes of the inoculation team and found their way into the inoculation room and into the product.
There was no obvious failure: no spill, no breach, no visible dirt. But that was exactly the issue. The sluice was seen as a neutral zone, not a hygiene-critical space. It slipped through the mental filters.
In hindsight, we should have observed the rising contamination pressure earlier through proactive air quality measurements in the sluices – before the contamination reached the incubation stage.
But once the first signs appeared, our monitoring framework allowed us to move quickly. Our environmental checks gave us the clarity we needed to trace the issue, identify the root cause, and prevent further loss.
Hygiene Is A Mentality
This incident reinforced a core principle we actively promote at Mycelia Academy: hygiene is not a task – it’s a way of thinking. It’s the ability to anticipate risk in places that appear clean. It’s about questioning routines, testing assumptions, and designing systems that don’t just look sterile – but are proven to be.
And that mindset requires feedback.
Good hygiene isn’t just about clean hands – it’s about monitoring and awareness. You can’t trust what you don’t measure. Air quality tests, inoculum checks, traceability protocols – these tools make your hygiene mentality actionable.
Monitoring doesn’t just show you where things went wrong. It shows you where things will go wrong – if you don’t intervene.
The Onboarding Lesson
We didn’t need to overhaul anything. The system was solid. But this incident reminded us that onboarding is a critical moment – one where hygiene awareness needs extra attention. It wasn’t about fixing a gap; it was about staying sharp, especially when routines are being passed on.
More Than Clean – A Culture Check
So if you work in sterile production, ask yourself:
- Do your teams understand why they clean - not just what they clean?
- Are you monitoring your environment - or just assuming it’s good enough?
- Is hygiene something people practice - or something they believe in?
