Mold Bacteria Consulting Services

Serving Ontario and British Columbia

You are here: Home / iBlog

Mould and food spoilage

Mould not only contaminates our air but also contaminate our food. As the mould grows on food it produces enzymes that break down the food resulting to spoilage. In addition to enzymes, some moulds such as Aspergillus flavus also produce mycotoxins onto the food. Ingestion of mycotoxin-contaminated food is fatal. Hundreds of people in developing countries die every year after consuming grains contaminated with mycotoxins.

Food spoilage due to mould includes off-flavours, mycotoxins contamination, discoloration, and rotting. Spoilage can occur either in the field or in storage. The water activity of the food determines the types of mould spoiling the food.

Moulds commonly found on cereals, nuts and their products.
Aspergillus candidus
Aspergillus flavus
Aspergillus glaucus
Aspergillus niger
Aspergillus ochraceus
Aspergillus parasiticus
Chrysonilia sitophila
Fusarium spp., e.g., Fusarium graminearum
Penicillium citreoviride
Penicillium citrinum
Penicillium expansum
Penicillium islandicum
Penicillium stoloniferum
Penicillium verrucosum
Rhizopus stolonifer

Moulds commonly found on high sugar foods.
Aspergillus glaucus
Penicillium corylophilum
Wallemia sebi

Moulds commonly found on fruits and vegetables.
Alternaria spp
Aspergillus niger
Botrytis cinerea
Cladosporium spp
Fusarium spp
Gloeosporium spp
Penicillium digitatum
Penicillium expansum
Penicillium italicum
Rhizopus stolonifer
Sclerotinia spp

Moulds commonly found on animal products such as meat, eggs, fish and milk
Aspergillus spp, e.g., Aspergillus versicolor
Eurotium spp, e.g. Eurotium herbariorum
Penicillium spp. e.g., Penicillium commune
Scopulariopsis spp.

Do you have a question on mould? Send it to My Question.

Indoor Mould And Bacteria

Proliferation of indoor mould and bacteria in dwelling places could lead to ill-health of the occupants. Indoor microbial growth and dampness has been associated with a number of respiratory problems including:

  • Respiratory symptoms such as coughing and wheezing.
  • Respiratory infections such as aspergillosis.
  • Allergic diseases, including allergic asthma and bronchitis.
  • Non-inflammatory, unspecific symptoms, e.g., eye and skin irritation, fatigue, headache, nausea, and vomiting.

The best way to control microbial growth in a building is to ensure the building is well maintained and any water leaks are repaired promptly.

Once mould has grown in a building, the solution to the problem is to have the water source identified and repaired and the mould removed. This can be expensive especially if the work is to be performed by professionals.

To avoid expensive mould investigation and removal, the homeowners and property managers should:

  • Continuously monitor for any water leaks and have them repaired promptly.
  • Continuously monitor for mould growth so as to detect it before it spreads.

Do you have a mould question? Send it to My Question.

Indoor Mould: The Mould Fusarium

Fusarium species exist as plant pathogens or saprophytes on plant debris and in soil. Plant parasitic Fusarium cause wilting of many plants including crops such tomatoes, bananas, sweet potatoes, pigeon peas, and pears. Some species of Fusarium are commonly isolated from seeds especially those of cereals. Species of Fusarium also produce a number of different mycotoxins which include trichothecenes (T-2 toxin, HT-2 toxin, deoxynivalenol (DON) and nivalenol), zearalenone and fumonisins. The Fusarium species are probably the most prevalent toxin-producing fungi of the northern temperate regions and are commonly found on cereals grown in the temperate regions of America, Europe and Asia. These toxins have been shown to cause a variety of toxic effects in both experimental animals and livestock and are also suspected to cause toxicity in humans.

In indoor environment Fusarium species are commonly found under very wet conditions. They are commonly isolated from carpet and mattress dust; damp walls, wallpaper; polyester polyurethane foam; humidifier pans and other areas where stagnant water occurs in HVAC systems. Some species cause keratitis in man, and infects eyes and finger nails. Fusarium species are also an inhalation hazard.

Do you have a mould problem or question? Send your question to My Question.

Mould Allergies

Moulds have a protein and polysaccharide components that make them potentially allergenic to sensitized individuals. Due to their small size, mould spores are able to penetrate deep into the respiratory tract where they can elicit allergic reactions. There are 2 types of respiratory allergy, the type I allergy (immediate hay-fever or asthma) and the type III (delayed farmer’s lung). Type I allergy occurs only in atopic (allergic) individuals.

Type I allergy may be caused by plant pathogens such as Tilletia caries, Fulvia fulva, and Leptosphaeria nodorum. Saprophytic moulds such as Cladosporium herbarum and Alternaria spp occurring in indoor environment or from rotting vegetation can also cause type 1 allergy. Mouldy straw, hay and decaying leaves are important sources of allergenic moulds such as Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger, and Penicillium spp.

There are occupational pulmonary and epidermal allergies. The former occur in the cheese industry (Penicillium roquefortii), the breweries (Aspergillus clavatus), mushroom farms (Doratomyces sp) and compositing sites (various moulds). An example of epidermal or skin allergies is the cane harvesters allergy caused by Arthrinium sp.

Do you have a mould question? Send it to My Question.

Indoor Mould: Do Not Panic!

Phrases like toxic mould or black mould are common on advertisements and the media. These phrases create fear, panic and confusion. It is a fact that exposure to mould can result to ill-health. However, some decisions on mould are based on fear rather than facts.

What You Should Know About Mould

  • Mould is found everywhere. However, growth of mould at 60% relative humidity is highly restricted. We can therefore, control indoor mould growth by providing adequate ventilation and maintaining indoor humidity levels at 60% or less. When excessive moisture or water accumulates indoors, mould growth will often occur, if the moisture problem remains unnoticed or un-addressed for more than 48 hours. The key to mould control is timely maintenance and prompt repairs.
  • About 150 different types of moulds occur in indoor environment. But not all these are harmful though to be safe it is better to treat all moulds as potentially harmful. The colour of the mould does not determine whether it is harmful or not. Therefore black mould is not necessarily bad mould. Mould related health effects depend on:
    • types of mould present,
    • amount of mould one is exposed to and for how long,
    • individual health status or sensitivity. Children, elderly and sick people are more vulnerable to mould.
  • It is difficult to eliminate all mould and mould spores in the indoor environment. However, the levels can be minimised by controlling growth. Monitor mould growth by looking for water stains or discoloration on the ceiling, walls, floors, and windowsills.

What You Should NOT Do When You Find Mould

  • Disturb the mould without proper personal protection and the protection of occupants.
  • Try to clean more than 10 square feet of mould contamination if you are not trained to handle mould.
  • Cause panic among the building occupants.
  • Use a chemical to control indoor mould if such a chemical is not registered for mould control in indoor environment.Do you have a question on mould? Send it to My Question.

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. […]