The hidden dangers of mould – part two
In part one we reviewed mould and recommendations on how to prevent mould growth. In this part of a two part series we will review different types of mould and the methods to safely clean a small amount of mould.
There are many different types of mould from the easily identifiable mould on decaying food which we are all familiar with to those moulds found in damp areas.
The most common moulds are as follows:
- Penicillium Notatum - is widely distributed in soils and can also be isolated from decaying vegetables and leaves. It is found on stored cereals and hay. In-house, this mould is the green-blue mould found on stale food and it is the mould that is used in the production of blue/green mouldy cheese. This mould is associated with indoor allergy.
- Cladosporium Herbarum - is the most frequently encountered mould in the air. Indoor concentrations of the spores reflect the outdoor concentration as this mould is easily transported through the air. Cladosporium is one of the most common colonisers of dead plants and soil. This is the mould that is frequently found on uncleaned refrigerators, foodstuffs, window frames, straw, houses with poor ventilation and in low damp areas. This mould has also been isolated from fuel tanks, face creams, paints and textiles. It is the primary source of mould allergy.
- The Stachybotrys chartarum species of mould, also called black mould or toxic black mould. Toxic black mould causes serious symptoms and health problems such as mental impairment, breathing problems, damage to internal organs and sometimes even death. The trichothecene mycotoxins produced by toxic black mould are neurotoxic. This means they can kill neurons in the brain and impair a person's mental ability. They also cause nervous disorders such as tremors and can cause personality changes such as mood swings and irritability.
- Trichophyton Rubrum and Pityrosporum Orbicculare - are yeasts that live within the skin in certain types of eczema.
- Aspergillus Fumigatus - is found in soils, leaf and plant litter, decaying vegetables and roots, bird droppings, tobacco and stored sweet potatoes. This mould is associated with asthma, also with bronchitis and conditions such as Farmer's lung.
- Alternaria Alternata - found in soils, foodstuffs and textiles. The most common habitats for this mould are rotten wood, composts, bird's nests and forest plants. Black spots on tomatoes and other foods are attributed to this mould.
Some types of mould are highly toxic. The first thing to do is to assess if the mould can be cleaned. If there is a relatively large area to clean then the decision is made to contact a specialist who will professionally clean mould in a safe manner. As a general rule only attempt to remove mould if it is due to condensation and less than one metre squared (1x1 metre or 3x3 feet). Don’t try to remove the mould if it’s caused by sewage or other contaminated water. Contacting a specialist is the advisable route to take for large areas of mould. In addition for severe mould infestation, contact the environmental health department of the local authority for advice and assistance, as they will be able to give good guidance of what to do.
Clean up of small amounts of mould
Personal protective equipment (PPE)
The person carrying out the cleaning of a mould should ensure they have the correct personal protective equipment. The mould cleaner must be protected from mould spores (tiny particles released by mould) by wearing eye protection, long rubber gloves and a mask that covers the nose and mouth. A disposable coverall is also advisable and a change of clothing which is cleaned after the clean-up completed.
Adequate ventilation is necessary but containment of spores essential. Open the windows but keep doors closed to prevent spores spreading to other areas of the building. Put up safety signage and ensure no person is allowed to enter the room whilst cleaning is being completed.
Prepare the environment
Prepare the environment and remove any items of materials such as soft furnishings, clothes etc that are mouldy. Dispose of any items that are not easy to clean.
- Use a wash basin containing water and a 1-to-8 bleach/water solution. In addition there are chemical solution products on the market for to help with cleaning mildew and mould. Ensure that the instructions are followed carefully.
- Contain the mould with the wet cloth and carefully wipe the mould off the wall. Be careful not to brush it, as this can release mould spores. The bleach in the cleaning mixture kills the mould.
- If the mould doesn’t disappear after light scrubbing, reapply the cleaning mix for a couple of minutes. Then lightly scrub again.
- When the cleaning is finished, use a dry cloth to remove the moisture from the wall. Dispose of all cloths used on the cleaning of the mould.
- Don't mix ammonia or any detergent containing ammonia with bleach. The combination forms a poisonous gas.
- As a further precaution all the surfaces in the room should be thoroughly cleaned by wet wiping to remove any spores.
Inspection for further outbreaks
After the clean-up has finished allow the area to dry and then check for any signs of new mould growth. Any further growth need to be investigated to understand the cause.
QCS has policies on infection control to meet your CQC requirements.
*All information is correct at the time of publishing