Mold Bacteria Consulting Services

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Indoor Air Testing For Mould

There are a number of methods that can be used to test air for airborne mould spores and fragments. The method chosen would depend on the objective of the investigation and subsequently the type of data required. The following methods can be used for testing air for airborne mould contamination.

Settle Plate Method For Detecting Viable Airborne Mould Spores And Fragments
With this method, a set of plates containing suitable growth media is exposed at table‑top level for half-hour to 4 hours. The mould spores and fragments suspended in the air settle by gravity onto the growth media. Light particles that remain suspended in the air for many hours are likely to be missed out. However, it is the cheapest way of sampling air since no other equipment is needed.

Volumetric Air Sampling For Detecting Viable Airborne Mould Spores And Fragments
The settle plate method is generally not recommended. A better method involves impacting a known amount of air on some suitable growth media. The media could be liquid or solid. With this method viable spores or vegetative material would form visible colonies (referred to colony forming units) in the media. These are counted in the lab and expressed as colony forming units (CFU) per cubic meter of air.

Volumetric Air Sampling For Detecting Total Airborne Mould Spores And Fragments
One disadvantage of impacting air on growth media is that only the viable propagules can grow on the media and hence detected. It is estimated that only about 10-15% of the mould spores may be viable. To enable us have a better estimation of how contaminated the air is, air is drawn on onto some inert sticky stuff. Depending on the efficiency of the sampling equipment used most of the spores and other airborne particulate matter including insect parts, pollen grain, and all sorts of fibres are trapped onto the sticky surface. Since these samples are directly examined under a microscope, the analyst is able to count the spores and vegetative fragments and express them as spores per cubic meter of air. It is also possible to identify some of the spores to genus level.

For more information on mould sampling visit our web page http://www.moldbacteria.com/sendingsamples.html.

Why Do Some People Get Sick From Mould And Others Do Not?

Why do some people get sick from mould and others do not? It is because of genetic and physiological differences. Sensitivity to mould in about 20 % of the human population is believed to be hereditary. Other factors that influence individual’s resistance to mould include age and general health status. For example, infants, the elderly and those recovering from diseases may be at risk of mould exposure even at levels that would otherwise be considered “normal”.

Susceptibility differences among individuals and the variability of moulds in their ability to cause health problems make it difficult to determine and set permissible exposure levels for indoor moulds.

Can You Paint Over Mould On The Shower Ceiling?

Recently we were asked whether it would be OK to paint over mould on the shower ceiling. Painting over existing mould is probably not a good idea because the mould may continue growing beneath the paint film and subsequently the paint would start peeling off. The best solution would be to clean the mould following current mould remediation guidelines such as CCA 82 – Mould Guidelines for the Canadian Construction Industry and then find a way of reducing condensation in the shower. Painting after the mould has been cleaned and the condensation problems fixed would be OK.

What is the Difference between Moulds and Bacteria?

Recently one of our website visitors wanted to know the difference between moulds and bacteria.

Moulds and bacteria are very different organisms. They are genetically unrelated. Moulds are larger, complex and grow as long, multi‑celled filaments (hyphae). Those filaments can aggregate to form larger masses (referred to as mycelia) visible to unaided eye. That is why we can see mould growth, for example, on a wall surface. Bacteria are smaller, single-celled and less complex. Requirements for growth and the means of reproduction for moulds and bacteria differ in many aspects.

Do you have a mould problem? Call (905)290-9101.

Should People Be Concerned About The Black-Brown Spots On Bananas?

Recently we received the following questions:

> Questions: It is my understanding that a mould, common in the
> common, commercial banana, has carcinogenic properties. I am under
> the impression that the blackening of the banana flesh may, usually,
> be attributed to the mould, and not merely oxidization.
>
> I presume the carcinogenic chemicals would be secreted by the
> mycelium of the mould.
>
> I also presume, as found in the secretions of other fungi, that the
> chemicals are hardy and not easily degraded by cooking.
>
> If correct, then the common practice, of using discoloured bananas in
> cooking, may tend to be somewhat dangerous and should be discouraged.
>
> Have you information to support my assumptions, or can you refer me
> to other resources.

————————————————————————————-
Answer: It is true that the sunken black/brown spots on the banana fruit are due to a mould. The condition is referred to as anthracnose. The mould that causes the spots is called Colletotrichum musae. It is a post-harvest problem of banana fruits all over the world. Unless the banana is almost rotten the mould is usually restricted to the banana peel. The pulp is not affected. Anthracnose develops when dormant infections of Colletotrichum musae in the green peel resume growth as the fruits ripen.

Colletotrichum musae is not known to be carcinogenic. I have not seen any documentation of poisoning of humans or animals after eating bananas with anthracnose.

Banana with spots caused by Colletotrichum musae

Do you have a mould problem? Call us at (905)290-9101

Salmonella food poisoning and symptoms

Salmonella food poisoning has been a growing concern in recent news. It has frequently lead to recalls of beef, salads and organic products and, even peanut butter products. Salmonella food poisoning occurs when one eats raw or undercooked foods such meat, poultry, eggs or egg products. Properly cooked food can get contaminated with Salmonella if […]

Legionella pneumophila – Guidelines for Laboratory Interpretation

Legionella pneumophila is a Gram negative, aerobic bacteria that is characterized as an opportunistic pathogen. It is the cause of Legionnaires’ Disease, a severe form of pneumonia and, it is the cause of Pontiac fever, a non-pneumonic form of L. pneumophila infection. Legionella spp.’s mode of transmission is through aerosols or aspiration of contaminated water. The Public Health […]

The Indoor Mold Is An Early Warning Device

The mold (or mould, in the Queen’s English) has been the victim of a bad press. Mention the word and it conjures up an image of something rotting or in the process of decomposition. And yet, were it not for the mold that inspired the discovery of penicillin millions of lives would have been lost. […]