There are multiple factors that will influence the growth of mycotoxins.
Some of these include the temperature, humidity, the type of surface, and most importantly, how much moisture is available.
The humidity and type of surface are factors that we have the most control over. Look at the table from a study looking at mould growth in a water-damaged building.
A study showed that homes with walls that are made up of cellulose, synthetic material, or gypsum have a lot more mould and mycotoxins than homes made of plaster or mineral wood. Hence, the older homes are safer than newer homes. Newer homes are more often built with synthetic material and drywall, where older homes more often have plaster walls, bricks, or stone.
What are the options for testing mould?
When testing mould, there are four common options: Air samples, ERMI, HERTSMI-2, and EMMA-mould count.
The first test (air samples) is a direct assessment by counting spores on a microscope, and the following three of these tests are PCR (polymerase chain reaction) tests which look for DNA from fungal species in dust samples.
Air samples are a cheap way to test mould spores. Using a vacuum-like device, the spores are impacted unto a slide which has an adhesive attached. A lab then counts the number of spores on the slide and then multiples that number in relation to how much air was pulled through the device.
The ERMI test is based on data from the EPA . There are 36 different moulds in these tests. There are 26 water damage moulds and 10 common moulds.
HERTSMI-2 (Health Effects Roster of Type-Specific Formers of Mycotoxins and Inflammagens-2nd version) was developed by Dr. Ritchie Shoemaker to look at what he decided were the five most dangerous moulds. The data from this report can be used to produce a score by using the spore counts from the five different species, i.e.: A spore count of Aspergillus versicolor of over 500 will be 10 points. Some individuals use a score of 5 and below as safe, while others use a score of 10.
The fourth mould test is the EMMA-part 1. I call this part 1 because the EMMA is actually two tests, a mould test and a mycotoxin test.
Testing for mycotoxins is more important than just testing for mould
Testing mould is important and probably the most common way to test for home toxin issues.
Mycotoxins are the toxins produced by mould. When moulds feel threatened, they produce these metabolites. The types of toxins produced are dependent on the species of mould, the environment the mould is growing, and the food source.
As mentioned earlier, the EMMA [is a combo test with two parts, and the second part is measuring mycotoxins. Mycotoxins, which are molecules, are over 1000 times smaller than spores. Mycotoxins have the capacity to infiltrate areas of a building that spores may be unable to reach. In many instances, especially with Stachybotrys, you will not find mould spores in the main living area, but you will find mycotoxins. This is because spores are multiple folds larger than mycotoxins and, in many instances, they are sticky. Spores can easily be trapped behind a wall but can still affect the inhabitants because of the toxins they release.
Besides testing your house, you should be looking into preventive measures. Measuring humidity and moisture are important elements in mould growth.
Keeping your home between 25-55% humidity will maximise your health and minimise the threat of mould growth. Studies indicate that moisture damage and mold in the main living areas of the house are the most correlated with adverse respiratory effects (Karvonen et al., 2015; Kirjavainen et al., 2016; Mustonen et al., 2016). In addition, moisture damage in the building is correlated with harmful outcomes for those that live/work in the building (Park, Schleiff, Attfield, Cox-Ganser, & Kreiss, 2004). One important number is the water activity (aw) ( aw x 100 = % relative humidity at equilibrium), and the longer a material’s aw is over 0.75, the greater the risk for fungal growth (Nielsen, Holm, Uttrup, & Nielsen, 2004).
If you have any questions, feel free to contact our team. We can provide insight into both clinical and home testing.
