ATHENS, Georgia, USA – A new research from the University of Georgia shows that cold brew coffee could be “the perfect playground for foodborne pathogens”. Angela Parra, a graduate research assistant at the Center for Food Safety in the Department of Food Science and Technology, is testing this exact subject on the UGA Griffin campus, reports Lillian Dickens is the communications, public relations and program coordinator for the UGA Department of Food Science and Technology on the college website.
Working with her advisor, Henk Den Bakker, a professor of food safety in College of Agricultural and Environmental Sciences, Parra has been inoculating cold brew coffee with different types of bacteria, such as Bacillus cereus, Listeria monocytogenes, E. coli and Salmonella.
“Specifically, I’m looking at the safety of cold brew and whether bacteria can grow in it. 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,” Parra said.
The main reason that these dangerous bacteria may grow or survive in cold brew coffee is also one of the main benefits of the drink: low acidity.
Low acidity can be a good thing when it comes to coffee. If a person experiences heartburn, bloating, indigestion or other stomach issues after drinking a regular cup of coffee, it is more than likely the acidity of the coffee that is causing the issues.
In a country where roughly 65% of the population drinks coffee by some estimates, low-acid alternatives have become a popular option.
Unfortunately, the acid and heat of coffee is what kills off pathogens like Bacillus and E. coli.
“The boiling water you use to make coffee is a form of temperature control against bacteria. That lack of control, put together with the low acidity found in cold brew, allows for the potential growth or survival of those bacteria,” Parra explained.
However, lovers of cold brew do not have to quit the drink or throw out their do-it-yourself cold brew pitchers, as Parra has not found that the bacteria will grow in cold brew if it is not already present.
“During my survival studies, at no point has the bacteria grown in cold brew. 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,” Parra said.
In other words, if brewed and stored in a refrigerator, cold brew coffee will not spoil and bloom bacteria that will make you sick. Contamination occurs during the process of brewing the coffee, such as contaminated ingredients or an unsanitary brewing environment — think an unclean coffee pot or unwashed hands.
Preventing contamination of cold brew coffee is an easy feat. If brewed at home, make sure to wash your hands and all the equipment being used, and remember that cold brew coffee is safest stored in the refrigerator.
