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https://www.the-scientist.com/a-mysterio...t-us-75114
EXCERPTS: This was one of the worst cases of damaged cheese that emerged during a years-long investigation run by Wolfe and his colleagues, in which they have fielded queries from multiple mold-bothered cheesemakers in the northeast United States. The first call came in 2012. Goat milk cheese left to ripen in a cheese cave had developed large black, flaky patches. Other cheesemakers also reported similar issues in 2019 and 2023.
Now, Wolfe and his colleagues have exposed the culprit. In a study published in Applied and Environmental Biology, they explained how they identified the cheese-wrecker as Aspergillus westerdijkiae, a toxin-producing species of fungus that, to their knowledge, has never before caused such problems for food production supply chains in this part of the US.1 It begs two questions: Where did the fungus come from, and how can cheesemakers beat it?
[...] Because A. westerdijkiae comes from a group of Aspergillus fungi known to produce a toxin called ochratoxin A (OTA), the researchers placed spores from each of the isolates onto cheese curd-containing agar plates to see whether they would grow and produce OTA under lab conditions. Liquid chromatography-tandem mass spectrometry confirmed high levels of OTA, especially in the strain isolated in 2012, which yielded mean levels of 54,455μg/kg. The US Food and Drug Administration recommends referring foods for safety assessments when OTA levels exceed just 20μg/kg.5
OTA is a “very nasty” toxin, said Jae-Hyuk Yu, a microbiologist at the University of Wisconsin-Madison who was not involved in the new research. It is a carcinogen that can cause kidney damage and other health issues. “I think it’s important for cheesemakers and consumers to know about this,” added Yu. Carol Verheecke-Vaessen, an applied molecular mycologist at Cranfield University who was also not associated with the research, praised the team’s use of what she called “state-of-the-art” techniques.
[...] Based on the team’s findings, Wolfe has advised cheesemakers to keep their cheese caves to a maximum temperature of 11°C. “They’ve all done that. We’ve gone back to their caves, and the fungus is gone,” he said. While maintaining lower temperatures has increased cheesemakers’ expenses and slightly slowed the cheese ripening process, “it’s much better than having cheese that’s really damaged,” said Wolfe.
He hypothesized that climate change could be one factor behind the emergence of this fungus in cheese caves, if rising average outdoor temperatures are making it harder for cheesemakers to keep their storage facilities cool. “During these really, really warm summers you just elevate the risk of this mold coming up.” (MORE - missing details)
EXCERPTS: This was one of the worst cases of damaged cheese that emerged during a years-long investigation run by Wolfe and his colleagues, in which they have fielded queries from multiple mold-bothered cheesemakers in the northeast United States. The first call came in 2012. Goat milk cheese left to ripen in a cheese cave had developed large black, flaky patches. Other cheesemakers also reported similar issues in 2019 and 2023.
Now, Wolfe and his colleagues have exposed the culprit. In a study published in Applied and Environmental Biology, they explained how they identified the cheese-wrecker as Aspergillus westerdijkiae, a toxin-producing species of fungus that, to their knowledge, has never before caused such problems for food production supply chains in this part of the US.1 It begs two questions: Where did the fungus come from, and how can cheesemakers beat it?
[...] Because A. westerdijkiae comes from a group of Aspergillus fungi known to produce a toxin called ochratoxin A (OTA), the researchers placed spores from each of the isolates onto cheese curd-containing agar plates to see whether they would grow and produce OTA under lab conditions. Liquid chromatography-tandem mass spectrometry confirmed high levels of OTA, especially in the strain isolated in 2012, which yielded mean levels of 54,455μg/kg. The US Food and Drug Administration recommends referring foods for safety assessments when OTA levels exceed just 20μg/kg.5
OTA is a “very nasty” toxin, said Jae-Hyuk Yu, a microbiologist at the University of Wisconsin-Madison who was not involved in the new research. It is a carcinogen that can cause kidney damage and other health issues. “I think it’s important for cheesemakers and consumers to know about this,” added Yu. Carol Verheecke-Vaessen, an applied molecular mycologist at Cranfield University who was also not associated with the research, praised the team’s use of what she called “state-of-the-art” techniques.
[...] Based on the team’s findings, Wolfe has advised cheesemakers to keep their cheese caves to a maximum temperature of 11°C. “They’ve all done that. We’ve gone back to their caves, and the fungus is gone,” he said. While maintaining lower temperatures has increased cheesemakers’ expenses and slightly slowed the cheese ripening process, “it’s much better than having cheese that’s really damaged,” said Wolfe.
He hypothesized that climate change could be one factor behind the emergence of this fungus in cheese caves, if rising average outdoor temperatures are making it harder for cheesemakers to keep their storage facilities cool. “During these really, really warm summers you just elevate the risk of this mold coming up.” (MORE - missing details)