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Dublin: 23 °C Monday 25 June, 2018

Antibiotic-resistant faecal bacteria have been found in health supplements in Irish shops

The algae-based ‘superfoods’ claim to offer a range of benefits including increased energy.

Spirulina, file photo.
Spirulina, file photo.
Image: Shutterstock/Ketta

A RANGE OF popular health supplements have been found to be contaminated with faecal microorganisms which are resistant to certain medicines, a new study from Irish researchers has revealed.

The study looked at samples of three algae-based ‘superfoods’ - Super Greens, Spirulina and Chlorella – which have become widespread in recent years.

The supplements claim to offer a range of health benefits including lowering cholesterol and blood pressure and boosting energy.

The researchers studied eight samples of the supplements (five Chlorella, two Spirulina and one Super Greens) which were bought in stores in Ireland.

All eight of the samples were found to contain gut microorganisms including clostridium, enterococci and enterobacteriaceae.

“Public health concern”

The researchers noted that the products are often consumed without cooking, offering no chance for the bacteria to be destroyed.

The study notes:

This project indicates that these algae-based products, promoted as food supplements with claims of health benefits, and often consumed without cooking… are frequently contaminated with faecal type bacteria, which in some instances carry antimicrobial resistance determinants of significant public health concern.”

Half of the samples contained a bacteria called Cronobacter sakazakii which has been associated with outbreaks of serious infection in neonatal intensive care units and in adults with an impaired immune system.

The packaging on the products also made no indication that they were unsafe for infants or people with a weak immune system.

Drug resistance

The study also found evidence that some of the microorganisms are resistant to antibiotics.

“Anti-microbial resistance… found in other foods, especially meat products, is a well-reported phenomenon and consumption of contaminated foods is considered to be one mechanism by which humans acquire or become colonised with multidrug-resistant organisms,” the researchers noted.

This project indicates that these algae-based products… are frequently contaminated with faecal-type bacteria, which in some instances carry antimicrobial resistance determinants of significant public health concern.


All of the products are compliant with legislation in terms of traceability, food hygiene and safety and there are no microbiological criteria set out specifically in relation to food supplements in Ireland.

The research was carried out by the Department of Microbiology at Galway University Hospital and NUI Galway’s School of Medicine.

The findings were published in this month’s issue of the Irish Medical Journal.

READ: Could gut bacteria actually help reduce stress?>

READ: Explainer: What is Ireland doing to tackle antibiotic resistance?>

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Ceimin Burke

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