The Latest on Fermented Food and Health
The International Scientific Association for Probiotics and Prebiotics (ISAPP) assembled a panel of experts to develop a definition and scope for fermented foods. The aim of the consensus statement was to clarify what is and what is not considered fermented food, differentiate between fermented foods and probiotics, and review the evidence on safety, risks and health benefits of fermented foods.
Classification of Fermented Food and Beverages
The definition of fermented food, a category that includes fermented beverages, is “foods made through desired microbial growth and enzymatic conversions of food components”.1
All foods and beverages produced by fermentation are considered fermented foods, including products that are produced using live microorganisms but may include steps in the manufacturing process to remove the microorganisms from the finished product. Examples of products that are considered fermented food, based on the presence and absence of live microorganisms, include but are not limited to1:
(a) Live microorganisms present, unless heat-treated or pasteurised - Yoghurt, sour cream, kefir, most cheeses, miso, natto, tempeh, fermented vegetables, salami, pepperoni and other fermented sausages, boza, bushera and other fermented cereals, most kombuchas, some beers
(b) Live microorganisms absent - Bread, wine, most beers and distilled spirits, coffee and chocolate beans (after roasting), heat-treated or pasteurised yoghurt, cheese, sour cream, fermented vegetables, sausage, soy sauce, vinegar and some kombuchas
Products that are not considered fermented food include products that contain ingredients made by fermentation, non-fermented products that are supplemented with microorganisms, and chemically-derived versions of fermented foods. Examples of products that are not considered fermented food include, but are not limited to1: Chemically leavened bread, fresh sausage, vegetables pickled in brine and/or vinegar, chemically produced soy sauce, salted or cured processed meats and fish.
Fermented Food vs. Probiotics
Probiotics are defined as “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host”.2 Fermented foods and beverages often do not meet the requirements to be considered a probiotic because the products generally contain undefined microbial strains, in variable amounts, and their potential health benefits have not been demonstrated in well-controlled intervention studies.
On the other hand, a product could be considered a “probiotic fermented food” if there is evidence from well-controlled intervention studies that a specific microbial strain(s) in adequate amounts confers a health benefit on the host. Otherwise, products should be considered as “containing live and active cultures”.
Safety, Risks and Health Benefits of Fermented Food
The European Food Safety Authority (EFSA) regulates the use of microbial cultures in food. Microorganisms that do not raise safety concerns as components of food, including those present in fermented food, are granted with “qualified presumption of safety (QPS)” status.
Lactic acid bacteria (LAB), acetic acid bacteria, yeasts and moulds are the main microorganisms used in fermented foods. These microorganisms are non-pathogenic and do not produce toxins or harmful end-products.
(c) Health Benefits
Some human studies have shown that microorganisms in fermented foods can survive gastric transit and reach the large intestine alive, and therefore play a part in modulation of the gut microbiota.3-5 In addition, fermentation improves nutrient availability and produces bioactive compounds which may contribute to health.6 However, a better understanding is needed from well-designed studies to clarify the role the consumption of fermented foods and their respective live microorganisms have in human health.
Although there is still a need for a better understanding of the effects of fermented food in human health, the ISAPP consensus statement on fermented food allows a deeper insight of these products and their classification among researchers and manufacturers, which in turn enables better communication to consumers.
1. Marco et al. (2021) The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on fermented foods. Nature Reviews Gastroenterology and Hepatology. doi: https://doi.org/10.1038/s41575-020-00390-5.
2. Hill et al. (2014) The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the scope and appropriate use of the term probiotics. Nature Reviews Gastroenterology and Hepatology, 11:506-514.
3. Milani et al. (2019) Nature Communications, 10(1):1286.
4. Oozeer et al. (2006) Applied and Environmental Microbiology, 72:5615–5617.
5. Taylor et al. (2020) mSystems, 5(2): e00901-19.
6. Melini et al. (2019 Nutrients, 11(5): 1189.