We came across this post on social media stating that manufactured citric acid (MCA) is made from Aspergillus niger – a type of black mould.

The post shares the link to an article written by the author of the social media post, and published on LymeDisease.org. The article, titled “Are you unknowingly ingesting toxic mould” avers that citric acid is derived from Aspergillus niger and exposure to it could potentially be harmful to immunocompromised patients, such as those with Lyme disease.

Lyme disease is an infection caused by bacteria transmitted by a tick bite. If undetected, the illness can lead to complications including facial palsy, and inflammation of the brain and spinal cord. LymeDisease.orgadvocates for, among others, further research on Lyme disease and better patient care.

 

What is manufactured citric acid?

Citric acid is a weak organic acid that can be obtained from both natural and synthetic sources and has variousfunctions. It is commonly used as a food additive for flavouring and as a preservative. It is also added to other products such as cosmetics, to prevent bacteria growth.

Natural sources of citric acid are citrus fruits such as lemons. On the other hand, synthetic citric acid, also known as MCA, is produced using fungal fermentation. Aspergillus niger is used to ferment materials such as molasses or corn meal, which then produces citric acid through the fermentation process.

Although citric acid can be derived from natural sources, manufacturing it from citrus fruits is expensive, and does not sufficiently meet demands. Therefore, the citric acid listed in the ingredient lists of most foods and supplements is synthetic.

 

Why the concern about black mould?

The article states that while MCA is generally recognized as safe by the United States’ Food and Drug Administration, there have been no human trials performed to determine its safety. The author also avers that MCA “contains the potential of contamination by impurities and fragments of Aspergillus niger”.

The study referred to by the author was a series of 4 case reports, where researchers studied the inflammatory symptoms of 4 patients after MCA consumption. At the end of the study, the researchers hypothesised that contaminants from Aspergillus niger or the manufacturing process of MCA could remain in the final product which triggers inflammatory reactions.

However, they were unable to conclusively affirm that MCA was the cause of these inflammatory effects and called for additional research.

 

Is there mould in my food?

Fungal fermentation is not new. Scientists have produced other useful items, such as penicillin which is used in medicine as an antibiotic, by using mould.

Around 99% of the world’s production of MCA is developed from Aspergillus niger. Hence, it is highly likely that the citric acid that is in the products we consume is derived from Aspergillus niger. Citric acid and enzymesderived from Aspergillus niger are also permitted additives in Singapore.

Hence, it is true that MCA is produced using Aspergillus niger.

Although MCA is obtained from Aspergillus niger, MCA is not black mould. While someone with a genetic predisposition to black mould allergy may suffer inflammatory reactions after ingesting MCA, scientists have recommended further studies to determine the overall safety of consuming MCA on a long-term basis.