CHANGE in best practice mould management

[Vicki Cowan]

Morena,
Since my last post I have done some more work on this and found myself talking to new experts. They have advised me that vinegar is problematic and really the BEST solution is warm soapy water and good old elbow grease. So with my HPA and Beacon colleagues, we have revised what is best practice mould remediation for households. I am in the process of updating all the HPA manuals (no more vinegar spraying!). So can you all please read the attached adopt it as your best practice when talking to households. Feel free to print and use the pages in the attachment (household probably don’t need ref list…?).
Ngā mihi nui,
Vicki
PS for those who are interested, here’s the documentation of the mouldy journey I have been on. I wrote this for the Beacon and HPA team so when I say “we” I referring to both organisations.

In ensuring any change in our advice is based on robust knowledge I have been in touch with a couple of experts who were new to me/Beacon/HPA. They are:
• Dr Caroline Shorter, whose PhD was on mould and now works for University of Otago, Wellington in their Department of Medicine and researches links between poor health and mould (author in one of new references).
• Adrienne Burney, a microbiologist who is a director of Biodet Services in Auckland.
Both Caroline and Adrienne provided me with new information and have reviewed the attached paper and agree with the advice. They both gave me permission to confirm they have reviewed this.

We have now STEPPED AWAY from vinegar (and the idea of “killing” with any chemical). We knew that scrubbing and rinsing was critical but have found in consultation with the experts that physical removal with soapy water is the most effective method. Here’s some notes to document our shift away from vinegar.

1. Things that remain unchanged
• Beacon and HPA know water is the critical ingredient in reducing mould and have always had a “dry your house out” philosophy (for a suite of beneficial reasons). I think this info sheet reflects this: removal of moisture is front and centre in mould remediation, and this sheet is a comprehensive summary of residential moisture management for householders to consider.
• Clean mould when it appears. Physical scrubbing has been part of our advice: we knew about physical removal and HPA promoted that type of cleaning.
• This simple advice sheet is written as a resource for households. Advice is straightforward: remove moisture, clean mould, if you can’t get on top of these things get help from professionals/experts. We have always had tiered advice, we (HPA) talk to our HP and Health participants about having confidence in our 10 top tips and when to bring in the experts (e.g. EDAs certified HPAs). We specifically say to HP&Health teams that when mould is very extensive it is beyond their skills to address. At the higher level, our certified HPAs are as expert as we train and they also need to bring in specialists if there are issues beyond their training.
• We had originally stated “mould is bad for your health”. Health experts are nervous about such simple statements when the causal link between mould and health conditions is yet to be irrefutably proven. There is a growing body of evidence in the literature of “associations between poor health and mould/damp” – but no proof of the actual mechanism. We could argue that households need to be made aware of the health associations with mould and a simple statement like my first version is valid. But I have tempered the statement to say mould is “linked to poor health” to reflect the lack of causal evidence in the scientific literature.

2. Things that have changed from our previous advice: moving away from use of vinegar as a first cleaning step.

We had previously advised use of vinegar for these reasons:
• we all understood it kills mould (this is true but not all species and see below for the range of reasons that lessen this as a positive feature)
• we had understood that lower concentrations of vinegar were best (in fact I now find concentrations of household vinegar are already low and dilution unlikely to be best if we were to keep advising its use)
• vinegar is cheap, easily available (present in most households) and largely not toxic to humans. So on balance, comparing the range of chemicals being discussed to kill mould (bleach, alcohol etc) we considered vinegar the best option. Now we are advocating an even more benign approach – soapy water and elbow grease.

New knowledge that had lead us to the warm soapy water scrubbing advice in this sheet:
• I find that vinegar itself is problematic as if not rinsed can leave a sticky residue which attracts dust/grime to which you add moisture and make a perfect substrate for mould. Also mould can provide food for mould growth, scientists indeed grow mould in the lab on acetic acid agar….
• while we always had scrub, rinse and dry (after spraying with dilute vinegar), experts expressed concern that if households think vinegar kills they won’t scrub. We always promoted this as a valid concern with bleach…it is also so with vinegar.
• Physical removal is THE answer, it’s all about cleaning with detergent (experts say surfactant) to remove the actual mould AND the damp grease/dust/dirt which is acting as a substrate for mould. We really need to get away from the idea that a passive spray with a toxic-something is going to deal to mould.
• Warm soapy water is not adding anything else toxic to the situation, better for humans and effective against mould when ‘elbow grease’ added. So the earlier “kill” step has been modified to here is how to protect yourself from the mould while you are cleaning.
• We knew bleach is very bad for respiratory systems, eyes and skin. In addition I have been told there is research that hyper-chlorates bind with organic fungal matter to make an even MORE toxic substance that humans don’t want to be near… This detail is too much for this paper, just think we need to understand that we are ACTIVELY saying no to bleach in a way that we haven’t before. In this paper, for households we do this by promoting the ease of warm soapy water.
• Conversations about other recommended “kill” chemicals such as ethanol have not been proven as effective killers of mould (paper in ref list). They are also toxic and unhealth for humans.
• Most people I have spoken with in past months on mould mentioned that “elbow grease” is not studied well in the scientific literature, which largely confines itself to applying different ‘solutions’ onto limited species of mould grown in petrie dishes… So there is not a body of peer reviewed papers saying ‘housework’ is the best way to clean off ‘manageable’ mould (i.e. we say manageable is not too big an area, on cleanable surfaces).
• new references have been added with their internet links (think this page is beyond householder advice needs, it is included for people who might share the advice sheets).
• The material the mould is growing on is central and complex for a simple householder advice sheet. It is implied that if you can’t wash/scrub an area with warm soapy water and get it dry (e.g. wallpaper, carpets will be problematic) then you need help – it’s no longer the cleaning issue like windows, sills, hard surfaces… We address by indicating sometimes cleaning won’t work – you might have to throw out/replace.

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