Hello and welcome to this week's live stream. Today we're going to be talking about Unboxing a Do It Yourself (DIY) Mould Test Kit and you might be thinking to yourself, why is this important? Well, if you've ever had unexpected water ingress, you have probably thought to yourself, and gone straight to Google: how can I test my own indoor air quality? How can I test for mould myself?
You might've rung up some indoor air quality professionals and discovered that it's quite expensive to have someone come out to your property, and you might've thought to yourself, well I need to prove that I've got a mould problem in my particular property. Or you might be leasing a residential or commercial property and you might not be getting anywhere with your landlord or property manager, and in a sense these are the situations where a Do It Yourself Mould Test Kit is very, very useful.
And so today I thought it would be valuable to show you exactly what you get when you order a Do It Yourself Mould Test Kit, go through some of the examples, real world examples, and I'm going to be opening a kit that's just been returned to us for analysis, I'm going to show you what happens when I unbox this and find out what samples actually came out of this person's property. I'm going to be explaining how to go about acquiring or taking samples from your property, but before that I want to talk about a range of different kits that are available out there in the marketplace, and if you go on Google you will find that there are some simple to complex mould test kits out there.
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And ranging from the simple, we have ones like a pregnancy test where you will get a color reaction in a window when you add a sample to it and they're usually based on ELISA or enzyme-linked immuno assay technology, where a particular protein is being measured and forms a color reaction. There are others out on the marketplace that are based on dipstick technology, and they are used quite often in pathology testing, especially for measuring yeast in urine streams, for example, and they have a padal type morphology (testing panel) where you put them on a surface that you're interested in testing. And then yet there are others that use cloths or dust samples to work out what the concentration of microbes is in that dust sample that has been wiped over the surfaces in your home, and usually that uses molecular probes to speciate your fungi to a high resolution of accuracy.
But at the end of the day, I want to talk to you about classical microbiology using Petri plates, and Petri plates are particularly important and fundamental to microbiology, bacteriology, and in fact all of pathology testing because Petri plates allow the cultivation of bacteria, yeast and fungi, and you're able to grow them. And because you can grow them, you can then analyze what grows.
Now not everything can actually grow or culture out on Petri plates, so that's one of the reasons why when someone comes out to your property to do an indoor air quality investigation and look for mould, they're probably going to use some other techniques apart from Petri plate or viable culture. But certainly in terms of a Do It Yourself Kit, Petri plates are fantastic. But where did Petri plates come from? Well, they were invented 176 years ago by a person by the name of Petri of course, Julius Richard Petri, and he was working in the lab of another famous bacteriologist by the name of Robert Koch, and he is famous because he made the connection between the bacterium Anthrax as the cause of disease. And that's really, really, really important because he was the first person to make this connection between this bacterium and the Anthrax disease.
Now up until the time that Petri joined the lab, they were growing or culturing these microbes on slices of potato. And so Petri made the suggestion which has been implemented of growing the bacteria in nutrient broth medium, inside glass curved dishes. And that was the birth of the Petri plate. And we've moved away from glass Petri dishes to plastic Petri dishes. Now this is really, really, really important so that's some history of microbiology.
I want to talk to you as well about why you might actually elect to use a Petri plate based method or do it yourself method.
The first reason is that it's convenient. It allows you to test what you're interested in. It's really specific to whatever question you're after. If for example, you're a tenant and you just can't get any satisfaction out of your landlord or property manager, you can't get anyone to recognize that yes, you do in fact have an indoor condensation problem which is leading to mould all over your window frame or yes, you do have visible mould on the underside of the ceiling that has come through since you moved into this particular property or the back of your side table is now covered in mould even though you just moved in a couple of weeks ago.
So in those situations it may be more convenient for you to prove the point that you need to get someone else to have a look into the investigation of your particular property, and a Do It Yourself Mould Test Kit might be very suitable in those situations.
It's also price sensitive. The cost of a Do It Yourself Mould Test Kit is really $200 to $300, whereas if someone comes out and does a forensic level inspection of your home or office, you're probably looking at $2000 to $3,000 and certainly if there's a legal dispute, it may be considerably more to answer all the questions that need to be addressed.
So DIY, do it yourself testing means that it's suitable for anyone really, so you don't need any particular requirements, you don't have to inform your landlord or property manager, you just need to sample inside your home or office or car or wall-mounted air conditioner. So it gives you a lot of flexibility to test what you're interested in.
I should say that the results are highly quantitative, and I'm going to explain why they are quantitative and why this is important because we may need more than just a yes or no answer. So it needs to be a bit more informed than the pregnancy style test and it needs to be more than just visual evidence. We need to take the information from the Petri plate and someone needs to speciate this out at least to Genus level, and that's what happens when you send Petri plates back to at least our lab. And you're also going to get a connection made between the number of colonies that form on that Petri plate and the number of colonies in the air, that is the CFU per cubic meter of air.
Fortunately, because Petri plates were developed 176 years ago, there is a rich history of publications and documents that explain how to translate from the number of colonies on the Petri plate to a concentration of microbes in the air. I should add as well that these Petri plates are not just restricted to air testing, you can also use a swab to stroke that across regions of interest (ROI’s) that are valuable to you. So if you have mould that you can see, for example, on your internal window glass and yet the property manager is saying, "Well, it was clean before you moved in, it must be you," and you have this condensation phenomena happening every day, especially in winter, you have mould forming on the inside surface of the glass, it might be in your interests to prove that those spots are in fact viable mould.
And so you might elect then to use a swab to streak across the region of interest and see what will grow, and then prove that there is an indoor mould problem at your property. I should add though that the results from swab testing are not quantitative but do allow speciation at least to Genus, and the most important feature of Do It Yourself Mould Test Kits are that they give you visual evidence, and this visual evidence allows you to demonstrate to someone else at a glance that there are in fact differences in the growth that forms on the Petri plate in different rooms of your home. And so then you can explain that this room is causing you or a member of your family potential problems from a health perspective and you can say, "I believe it's due to this issue in this particular part of the home," and that's where Do It Yourself Mould Test Kits are particularly valuable.
People often ask, writing to us and ask us about the validity of the test kit. How accurate is it? Well, mould testing using settling plates as opposed to putting a Petri plate into a pump, have been around for decades and in fact are embedded in many guidelines and standards, and I'm going to highlight a couple of these for you.
There is a well known book produced by the American Industrial Hygiene Association and this is for how you go about testing an environment for biological contamination and they go to some lengths to talk about Petri plates and about the pros and cons of pumps and settling plates and the differences there. There are other literatures as well that talks about mould exposure standards, and this particular document lists dozens and dozens of expert documents that exist worldwide on how to establish thresholds for what is a problem, shall we say, in an indoor building relative to a normal mould ecology.
But this issue of using settling plates - settling plates have been around for generally decades really, and they have found a lot of utility in the assessment of indoor hygiene and cleanliness in clean rooms. And the reason why, is the clean rooms are designed and designated at different grades and you don't want microbes falling into your fine pharmaceuticals during production. And so therefore, settling plates have been used, as I said, for decades to assess how clean the room is. And so there are some wonderful threshold documents out there for determining the connection between the number of colonies that form on the settling plate and those in the air.
However, if you're still not convinced, as I was getting ready to prepare for this live stream, I did a search on PubMed, which is the resource that we scientists and members of the public use for researching what peer-reviewed publications exist that talk about relevant issues in science or medicine, environmental health, and I quickly found this fantastic paper which is in the references at the bottom of this livestream, when we post this, which came out in 2017, and they did a comparison between the settling plate method using Petri plates and a pump, and I'll quote from this paper: they found a high correlation coefficient between the impaction and sedimentation methods for Aspergillus niger, which is the fungus that they were doing their experiment with.
And so they found that there was a high correlation between the results of the pump or the settling plate, and they went on in their conclusion to state that, "Active and passive air sampling can be used for monitoring the air in clean rooms." They go on to say that, "For fungal spore detection, the impaction method using a pump is more efficient because it can do the work in a shorter period of time."
For example, when we go out on site with an air pump and Petri plates, we move room to room and the acquisition time is two minutes. However, with the settling plate method you have to expose the Petri plates for a fixed window of time, in this situation it's 45 minutes, so the results are pretty similar between the pump or the settling plate, and this is really an important fundamental property of Do It Yourself Mould Test Kits using Petri plates.
The other thing that I want to mention as well is that when the report is prepared for you, you are going to get visual evidence about what you can see and this is really, really, really important because sometimes all you need to do is show the information to someone else to prove that you in fact have a problem.
In any case, I'm now going to unbox one of the mould test kits that has just arrived at our office. Before we take it down to the lab, I'm going to open it here and then I'm going to show you exactly what we see when we get sent these all week. Okay, I'll move over to the next part.
So this is what happens when we send out these kits. They contain Petri plates, I'm now going to open this up.
This particular person has also not put their details on the back. It's a really good thing if when we are sent these, someone does put their return address on it. It's not necessary because they have hopefully returned the chain of custody paperwork, and the chain of custody paperwork should list their name, their address, and a whole bunch of other properties that we need at the lab, to write into your report.
Hopefully I can get this open fairly quickly and easily. It's always a... I never know what's going to happen even though we send these out all week. It's a bit like opening a present, at least for a microbiologist like myself. So when we get this back, we have... I'm going to not show you the person's name, so I'll just have a quick look at that. We send out a whole bunch of instructions, I'm going to cover up their name, and so they've sent back to us a sample from the living room ceiling wooden frame, which is a surface sample and they have a living room air sample.
So what we see here, I can handle these quite safely because we ask everyone to tape up the edges of the Petri plates, and we can see a couple of things. The living room air sample, which was done just a couple of days ago on the 12th of August, we will take this and incubate this. I can't see very much growth at the moment. That's from a typical air sample. We normally encourage everyone to always do an outdoor control, and I'll explain why in a little while, but we can tell from their swab sample from the living room ceiling and wooden frame, these are the type of information that we can see. So I can see some Epicoccum colonies, some Penicillium, and we can subculture further from here, at the lab if I need to make further identifications.
This particular person obviously is interested in what type of fungi is growing on their living room ceiling, and they want to know whether or not this is potentially impacting on their air quality. And even though this hasn't really grown for long enough yet and there isn't a control, I can immediately say that it is unlikely that the air quality is significantly impacted on by what is growing on the living room ceiling, and that's really, really, really important information. And so that's, at least for this person, what we can see.
Now I'm going to show you another example, I think. Just bear with me while I get it. Now this person sent us in four samples, and what I can see here and what I wanted to make the point of here is that they sent in a mould surface test from the hallway and this is what their swab samples looked like, and swabs are very useful because as I said, they don't tell you what the overall contamination in the room is, but they do prove that there is a contamination event in that particular location. But similarly this person is very interested in what happened in their lounge room, what happened in their bedroom, and now what happened in their caravan.
And you can, just on eyeballing this study, you can say a few things about it. There are more colonies growing in the lounge room than in the bedroom, and the caravan looks pretty good.
Now the reason I wanted to do this unboxing rather than doing this with pre-opened results is that, I want to highlight some of the things that I don't like as a scientist. I really need to see an outdoor control because I have no way of saying what the air quality is outdoors, but I can say that relative to the lounge room, the caravan looks pretty good. The bedroom is not as good as the caravan, but it's still better than the lounge room.
Importantly, I can tell you that that is a yeast called Rhodotorula. I can find other examples of Cladosporium fungus here, I can find yet more examples of some more Rhodotorula, some Penicillium, Aspergillus, some yeast Candida, and all of this is very valuable information which eventually makes its way into lab reports.
Since everyone who purchases a kit from us is not getting a haphazard set of photographs, we actually write the reports up, and I'll give you an idea about when you have a control. Here is an outside control and you can see that this had 42 colonies growing on it. Now that's really valuable information because that is the background level of mould or viable mould in the air, and we can now look at the master bedroom for example, and we can see that there are only three colonies that have grown here. Whereas the sub floor is quite similar to the outdoor at 41 which is consistent with what we would expect because the sub floor often, certainly for timber homes, is an outdoor environment. I've also done [counting] one from the roof space and only six colonies were observed here. I wanted to know also what their heating register was.
Again, they probably were concerned about whether or not moulds were being recirculated throughout the ductwork. So they've tested the heating register or put a Petri plate out there, and they've then probably gone to a school. We don't recommend really sampling from more than one building at a time, but as I said, when you do a Do It Yourself Mould Test Kit, it's not really as rigorous as if someone came out on site and did the work for you. You get control over what you're interested in. And so the issue with this particular family was they also tested out one of the girl's rooms and one of the family rooms. And so the conclusion was that the living environment, at least for the building, let's not talk about the school at the moment, was normal relative to the outdoor mould levels. And that is the benefit of doing a Do It Yourself Mould Test Kit.
So now I'm just going to discuss some of those situations where Do It Yourself Mould Test Kits would be most suitable. In this unboxing, a few things have happened. Firstly, I've opened a kit that doesn't have an outdoor air control. It makes it very difficult for us to make a definitive statement regarding the sample numbers that have appeared on your Petri plates relative to the outdoor control if you don't do an outdoor control. So I think it's absolutely fundamental that when you're doing a Do It Yourself Mould Test Kit using Petri plates, that air testing is definitely better than surface testing. And the reason being is that air testing tells you what you're breathing and that's really important.
If your question is only, what does that stain in the corner of the hallway which you know is leaking, well then swab test is most relevant to you. But like that example here where the occupants were interested in whether or not their living environment relative to the furniture sample was contaminated? You want to know whether you will be exposed to this in the breathing zone, so air testing, at least in my opinion, is more valuable than surface testing.
You must always do an outdoor control. We really need this information, it's fundamental to being able to make an assessment or risk assessment on what the results mean for you and your family. Because you do have control over where you do sample, you need to make a decision about what the region of interests are going to be, and these need to be meaningful to you. It's all well and good that I can criticize some of these samples and say, "I wish we had a control," but for those particular clients, this type of data should be highly specific and relevant to their situation. That's why you're doing a mould test kit yourself, rather than getting in an expert or some other type of professional.
As you've seen here, more samples are not always better, although too few samples don't give you enough information on which to make decisions. So there's a bit of a trade-off between collecting too much information and too little. The main thing from my point of view is that I want to know, are the occupants being exposed to something in the breathing zone? Now importantly, so basically this is samples and number. You want to get that meaningful and right for your situation.
The next point I want to make is that when you do this test, you need to do it in as a scientific way [as possible] you need to do it sensibly. So the instructions state, expose the Petri plate for 45 minutes. So make sure that every single plate is exposed for 45 minutes, and that doesn't mean one sample, 30 minutes, one, 2 hours, you need to make them consistent. So work out where you're going to be placing the Petri plates before you embark on the sampling exercise.
Importantly, you want to as closely mimic data acquisition from the breathing zone. So that means put the Petri plate on a chair or table. Don't put it on the ground because if you walk around and you've got carpet, you're going to be stirring up dust and debris and you will in a sense artificially inflate the number of colonies that can grow on that particular Petri plate. So basically you want to put the Petri plate on a chair or desk rather than the ground.
Also, you want to send these back soon after you have done the sampling. Trust me, if there's something there, they will grow. If it's not heavily contaminated, it's unlikely to grow significantly. Send it back so that we can put it into the incubator and see what's going to happen. Don't wait and watch it at home and then send it to us. Because if the concentration of viable microbes is really high in the air, if you hold onto the plate too long and don't get it back into the post, then it will have overgrown and it will become confluent or plate filling, and that's not good either.
Basically, so the next... Send back when finished. The last point is recognize that there are limitations to what a Do It Yourself Mould Test Kit can do for you. It is not going to take the place of an onsite forensic level indoor air quality and mould inspection, often accompanied by building defect analysis, that you can achieve with other experts, but it will give you some visual information and a report that in a sense gives you something to discuss, something to talk about, it is presumptive evidence. It allows you to open up a dialogue often with a landlord, property manager, builder or insurer, that there actually is a problem at your particular building, and that it does need to be further looked into.
And in a sense, that is the whole point of science. The whole point of it is to collect observations through reasoned experiments to allow you to make some decisions based on the collected information, and that's what mould test kits using Petri plates allows you to do.
In any case, my name is Dr. Cameron Jones, I'm an environmental microbiologist. Feel free to send your questions through, put them in the comments below, and I'll talk to you next week.
Bye for now.
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