Fermented Foods

Fermented Foods

Live Microbes and Fermented Foods

By Prof. Robert Hutkins, PhD

Fermented foods have seemingly all of a sudden become one of the most popular food categories. In part, this is because products like fresh yogurt, aged cheese, and spicy kimchi have aroma and flavors unlike any other foods. There is also, of course, the intoxicating appeal of a fine wine, craft beer, or single malt scotch.


Another reason for the popularity of fermented foods is because of the health benefits associated with many of these products. Wine, chocolate, and coffee, for example, are rich in natural antioxidants that promote heart health and fight disease. However, for many consumers, it’s the live bacteria that matters most. That’s because many of the bacteria found in fermented foods are associated with gut health and other benefits.

That’s not to say that the microbes responsible for fermentation are the same as the probiotic microbes often added to foods and supplements. Probiotics are known species with known functions and benefits.  Fermentation-associated microbes may nonetheless share many of the beneficial traits of known probiotic organisms.


Fermented Foods infographicWhile all fermented foods are necessarily made with microorganisms, some products are subsequently processed by heat or filtration. These steps are done to extend shelf-life and make the products shelf-stable, but they also inactivate or remove the organisms. Thus, fermented vegetables, like sauerkraut or pickles packaged in jars and stored at room temperature will not contain live cultures. For other fermented products, like sour dough bread, the organisms do not survive the baking process. Unfortunately, it’s not always easy for consumers to know which products actually contain live bacteria. Still, there are plenty of fermented foods with live cultures, but discerning consumers need to look carefully at the labels.


For products like yogurt, it’s usually not a problem, since many brands promote this fact on the label. Some products are even labeled with the “live and active cultures” seal. Depending on where you live, you may need to visit natural food stores to find pickles and sauerkraut that have live bacteria. Likewise, there are Asian-type fermented foods, miso and tempeh, for example, that are usually “alive”. Cheeses are hit or miss – fresh cheeses like cottage cheese are heated, and aged cheeses that aren’t heated nonetheless may not contain too many live bacteria, since most will die during storage.


Finally, if you don’t mind cloudy beer, there is a nice selection of microbrewed beers that aren’t filtered or heated and that contain live yeasts and bacteria.


People interested in adding live microbes to their diets are increasingly interested in fermented foods. A word about Prebiotics Foods.  A word about Probiotics.

Dr.Hutkins explains the difference between fermented foods and probiotics:  “Your guide to the difference between fermented foods and probiotics“.

About the author: Robert Hutkins, PhD, is author of Microbiology and Technology of Fermented Foods (2nd Edition, 2016) and a board member of ISAPP. He is the Khem Shahani Professor of Food Science University of Nebraska, Lincoln.