Cold brew coffee comes with chilling health risk, University of Georgia study finds

The quality that makes cold brew coffee taste smooth also can make it dangerous, University of Georgia research has concluded.

The findings are literally enough to make you sick. Scientists at UGA's Center for Food Safety in Griffin have been pumping cold brew coffee full of bacteria. Strains incude four common pathogens in food-borne illnesses: E. coli, salmonella, Bacillus cereus and Listeria monocytogenes.

“Specifically, I'm looking at the safety of cold brew and whether bacteria can grow in it," said Angela Parra, a graduate research assistant at the center. "I’m also looking at other aspects, like how the quality of ingredients can impact hygiene of the drink, temperature control and what conditions allow for the growth of these potential pathogens."

Cold brew coffee is made by steeping coffee grounds in cool or cold water for several hours. Cold brew's popularity has sprung 300% higher since 2016, according to a data trends report from the National Coffee Association.

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Hot coffee is mildly acidic, so many java lovers who want to avoid heartburn turn to lower-acid cold brews. But it's the acid and applied heat in hot coffee that kills off potentially harmful pathogens.

“The boiling water you use to make coffee is a form of temperature control against bacteria," Parra said. "That lack of control, put together with the low acidity found in cold brew, allows for the potential growth or survival of those bacteria."

There is cold comfort, though: Bacteria in cold brew don't seem to emerge on their own – only when they're introduced artificially.

“During my survival studies, at no point has the bacteria grown in cold brew," Parra said. "However, the pathogens have all survived within the coffee anywhere from nine to 12 days. Unfortunately, there is only a slight decline in bacterial counts in the days leading up to the complete inactivation of these pathogens – meaning freshly brewed cold brew can still make you sick."

That makes contamination prevention simple, according to UGA. When preparing cold brew at home, use clean hands and clean equipment, then refrigerate the brewed coffee.

This article originally appeared on Augusta Chronicle: Bacteria can thrive in cold brew coffee, UGA research concludes