Recently we received some questions from Australia on why eating food contaminated with mould is dangerous. We have posted the questions here together with our brief answers.
Q. Can you still eat food once you chop the mould off?
A. It is risky to eat food that is already contaminated with visible mould. As mould grows it tends to produce by-products (secondary metabolites) that permeate into the food or material it is growing on. Some strains of moulds such as those belonging to Aspergillus, Penicillium and Fusarium produce metabolites that are highly toxic.
Q. If there are foods you can eat after chopping mould off, what are they?
A. I would not recommend eating of any food that has previously been contaminated with mould because the person eating the food may not be knowing which mould is contaminating the food and whether the mould has produced toxins.
Q. What kind of moulds are unsafe to eat? Why?
A. All moulds are generally unsafe to eat. However, the risk is higher if one is to eat those moulds known to produce toxins (the so called toxigenic moulds). Some examples of toxigenic moulds commonly found on food are species of Aspergillus, Penicillium and Fusarium. Some species of these moulds are known to produce highly toxic metabolites. A good example is Aspergillus flavus which produces Aflatoxin. Recently aflatoxin killed 125 people in Kenya after eating contaminated maize.
Q. What are the conditions that are best for producing the toxins in toxigenic moulds?
A. The conditions that trigger toxin production by moulds are not well understood. However, genetic and growth conditions are known to influence toxin production. Growth conditions that may influence toxins production are food nutrient composition, pH of the food, moisture content and temperature.
Q. If mould is present on food, does this necessarily mean that bacteria causing food poisoning is also present?
A. If mould is present on food, this does not necessarily mean that bacteria causing food poisoning are also present.
Q. What are some of the symptoms that can be caused by eating toxigenic moulds? Are any fatal?
A. Symptoms of mycotoxin poisoning may depend on the root of entry into the body.
- Inhalation symptoms may include: nose and throat pain, nasal discharge, itching and sneezing, cough, wheezing, difficult breathing, chest pain and bloody sputum.
- Ingestion symptoms may include: nausea, vomiting, and watery or bloody diarrhea with abdominal pain.
- Contact Symptoms: burning skin pain, redness, and blurred vision (if the eyes are affected).
Severe poisoning can lead to death. Some Mycotoxins such Aflatoxin can also trigger cancer.
Q. Are there any ‘safe’ moulds that you can eat? Are there any moulds that may improve health by eating them?
A. There are no ‘safe’ moulds to eat. However, some moulds including some that are known to produce toxins have been used for many years in production of fermented food. Quorn is a high protein fungal product produced from a species of Fusarium. It is used as an alternative to animal protein.
Q. Can you mistake bacteria for mould? ie. do any look similar to the naked eye?
A. Bacteria and moulds are totally different organisms. Their cell structures are different. Their mode of growth is different and therefore easy to differentiate.