Yeast Commonly used in Food Industry May Induce Drug-Resistant Infections

A study recently published in PLOS Pathogens found that a strain of yeast commonly used in the food manufacturing process is genetically identical to one that causes intense drug-resistant infections. Pichia kudriavzevii, the fungus that is thought to be safe, has been used in food manufacturing and fermentation processes for fermented milk, maize beverages, and cassava for hundreds of years. The FDA recognizes its usage to be acceptable, and the fungus’s inclusion in food products has actually increased in recent years. Despite this accepted notion that P. kudriavzevii is a nonharmful fungus, little is known about its genetic makeup.

The most common cause of drug-resistant fungal infections are members of the Candida genus. There are five members of this genus of fungi, with Candida krusei being the least understood. In their study, the researchers aimed to determine the genetic similarity of C. krusei and P. kudriavzevii. Genetically sequencing 30 environmental and clinical strains of each fungi, the team concluded that the two fungi were of the same species, sharing 99.6% of the same DNA. In perhaps the most profound finding of the study, the researchers observed that both fungi displayed similar antifungal resistance.

Lead author Alexander Douglass notes that it may be wise to “to set limits on the levels of drug-resistance permissible yeast in P. kudriavzevii strains that are used in industry, particularly the food industry.” He also states that it may be wise to use non-pathogenic members of the Pichia species in place of this pathogenic strain.

The scientists note that the fungus has also been named as Issatchenkia orientalis and Candida glycerinogenes and claim that all these strains should be under the name P. kudriavzevii to avoid confusion.

Check out more in a series of dietary articles, next up is a look at how foodborne illness in the US

Source: Medical News Today