Black Mold in Food Processing

I’ve seen several articles on the Internet about the “dangers” of citric acid as food additives. Citric acid is a popular food additive that is used for many purposes, ranging from imparting a sour taste to preserving food freshness by retarding bacterial growth.  Among those who believe citric acid is dangerous, the most common reason cited is that it is produced by “black mold”, and people are frightened of black mold – well, all mold really. Although citric acid is contained in citrus fruits, it is economically and physically impractical to extract sufficient quantities from citrus to meet the demands of the food processing industry. Thus, in the early 20th century, a process was discovered that permitted the economical large-scale production of citric acid using a particular species of black mold. The process  involves nourishing the mold with glucose or other sugar solutions, and drawing off the citric acid that is produced via the mold’s metabolism of same.

But “black molds” are not at all identical.  Indeed, there are several different varieties, and there is one predominant species that is most commonly used to produce citric acid – Aspergillus niger (A. niger). A. niger has been used to produce commercially viable quantities of citric acid for about 100 years. There are numerous researchers and international agencies that have studied the safety of A. niger, and the overwhelming conclusion is that it is NOT pathogenic, and is quite safe to use (and to be around), with the possible exception of immune-compromised individuals, and even then, only if they are exposed to large volumes of A. niger spores – not their metabolites.  A. niger is surprisingly common in our environment – you are probably inhaling small quantities even as you read this article.  The body of literature concerning the safety of A. niger is considerable and beyond the scope of what I wish to present here. Follow this link for a fairly comprehensive literature review on the subject – it’s a good starting point, and I encourage you to convince yourself.

So what species of “black mold” strikes fear into the hearts of so many people? Well as I mentioned, there are many varieties of black mold, but the principal two (2) species which present the highest levels of pathogenesis are Stachybotry arta (S. arta) and S. chlorohalonata. These species of toxic black mold grow in wet, damp places (like basements, or water damaged buildings) and can generate prodigious volumes of mycotoxins. Please refer to the this article for basic background information, and this article from the CDC on the dangers of toxic black mold for more information.

Information and perspective are wonderful things. There are plenty of things in life for one to worry about, but citric acid isn’t one of them.

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