When it comes to viable sampling in cleanrooms and critical spaces, you’ve got two main media options: traditional petri plates and Rapid Micro Bio (RMB) cassettes. Both get the job done, but they do it in very different ways—and depending on your setup, timelines, and data requirements, one may be a much better fit than the other.
Let’s break down the real-world reasons teams lean one way or the other.
Petri Plates: Tried, True, and Familiar
Most cleanroom folks have been using petri plates for viable sampling forever—and for good reason. They’re simple, cost-effective, and everyone already knows how to work with them. They’re especially common in pharma and biotech environments where regulations have been built around traditional methods.
If your team incubates in-house, you’ve probably got petri plate workflows dialed in. The process is predictable, and results are usually available within 3 to 7 days, depending on the incubation protocol. For routine monitoring or regulatory compliance, this timing might be totally acceptable.
Real-world example:
A sterile injectable manufacturer runs daily viable air sampling on multiple ISO 5 areas. They use petri plates because the facility already has an in-house lab with validated incubation and identification systems. Their timelines allow for a 5-day wait on results, and they appreciate the cost savings of petri plates over time.
RMB Cassettes: Faster Turnaround, Cleaner Handling
On the flip side, Rapid Micro Bio cassettes are gaining serious traction—especially when speed, data integrity, or contamination control is top of mind. The RMB cassette is a closed system, which makes it much easier to handle in high-risk areas. Plus, some systems can start giving you results in as little as 24 hours.
That kind of speed can make a huge difference.
Real-world example:
A cell therapy facility is working with short-shelf-life products—every minute counts. They use RMB cassettes because they need viable monitoring results within 24 to 48 hours to release product safely. They’ve also found that the closed cassette system reduces false positives from operator handling.
Which One’s Better? Depends on What You Need.
There’s no “one-size-fits-all” here. If your main concern is cost and you’ve got the time to wait for results, petri plates will probably work just fine. But if you’re working in high-risk zones, handling sensitive product, or you simply can’t afford to wait five days for micro results, RMB cassettes are worth a serious look.
The good news? You don’t have to choose just one. Many facilities use both, depending on the area, process, and urgency.
So, what matters most to your team—speed, cost, handling, or risk reduction?
One System, Both Options: How Lighthouse Makes It Easy
Real talk: many facilities are juggling mixed-use areas, tight timelines, and strict compliance standards. The ability to plug-and-play between media types isn’t just nice to have—it’s a game-changer.
Need help figuring out which setup fits your team best? Lighthouse will walk you through it. Tell them what you’re sampling, how fast you need results, and how your system’s set up. They’ll help build a kit that works today and grows with you down the road.
