Fermented foods – Keep your friends close and functional microbes closer!

  • Shreya Choubey ,

AMA School of Medicine

Ever wondered what the modern age Adam and Eve would eat? It’s safe to say, my money is on fermented food. Little cooking required, delicious to the taste buds and packed with flavours – Fermented foods are just the statement food now. If you love eating your dosas, you have fermentation to thank for! But what is fermentation? Are these foods good for you? Let’s dive in.

Fermentation is a metabolic process in which organisms (such as yeast or bacteria) break down carbohydrates: B. Sugar or Starch to Alcohol or Acid. Fermented foods vary in composition and method of preparation in many cultures around the world. Some commonly found preserved food include: Kimchi (made up of cabbage, radish, and other vegetables and fermented with their own juices), Sourdough (dough baked after fermentation with lactobacillus and yeast), Jalebi (An Indian delicacy, made after deep frying fermented wheat), and Yoghurt (made by fermentation of milk), oh and the list is long! There are three significant types of fermentation – Lactic acid Fermentation, Ethyl Alcohol Fermentation and, Acetic Acid fermentation.

In many underdeveloped countries, fermentation serves as a critical preservation method as it is an inexpensive way of increasing shelf life, inhibits the growth of pathogenic microorganisms, increases product digestibility and comes with organoleptic properties (No wonder these foods have taken the world by storm!). The presence of fermenting microorganisms, their metabolites and the changing pH of the raw material inhibit the growth of pathogenic organisms. They are also a valuable source of functional microorganisms. A study by Zhang et al. (2016) showed that microbes in fermented foods could temporarily affect the gut microbiota and improve or reduce the risk of gut microbiota-related diseases. An example of the benefits of fermented foods on the gut microbiota is the reduction of symptoms of irritable bowel syndrome caused by the consumption of fermented probiotic milk containing Bifidobacterium lactis CNCM I-2494 (Marteau et al., 2013).

Fermented foods also help combat several mental diseases, as microbes can produce and respond to neurochemicals; they may play an essential role in treating depression and anxiety disorders (Romijn et al., 2017). If the gut and brain were any less, fermentation is here to help people suffering from oral diseases. The functional bacteria improve the oral microbiota by producing antioxidants that inhibit plaque growth and lower the pH. They also treat halitosis by breaking down the volatile sulfur compounds that cause halitosis (Gungor et al., 2015; Voidarou et al., 2020). In many parts of the world, especially in Asia, pathogens such as enterotoxigenic and enterohaemorrhagic Escherichia coli, Shigella spp., Salmonella spp., enterotoxigenic Staphylococcus aureus, Listeria monocytogenes, and Bacillus cereus are harvested from fermented foods.

But are fermented foods just about the goody two shoes? Not really. Even though fermentation is cheap and a fast process, the use of poor ingredients, maintaining low levels of hygiene, and lack of safety may pave the way for pathogenic microorganisms or their toxins in the food, which can increase the risk of getting contaminated products and in turn cause diseases or even outbreaks. In developing countries, the raw materials used to manufacture fermented foods vary in quality as the better raw materials are majorly exported. Limited access to water also encourages potentially contaminated water, which may increase the risk of E. coli and Salmonella spp. presence in food (Angogu et al., 2021). Despite the beneficial effects of fermented products on human health, consumption of fermented products introduces carriers of antibiotic and chemotherapeutic drug resistance genes into the body, causing multi-drug resistant infections that are difficult to treat. There is a risk of selection of resistant strains. Adverse health effects associated with fermented foods can include isolated illness, epidemics, and even death. Mycotoxins in some products can cause gastrointestinal tract illness, kidney stones, or long-term effects like cancer. High sodium content in traditionally manufactured fermented foods may also result in several health conditions.

There are certainly some drawbacks to eating fermented foods, but that doesn’t mean you should avoid them. Civilizations across the world have found several interesting ways to engage your tongues with their fermented delicacy. And as they say, a balanced diet with a little moderation, never hurts nobody!


  1. Zhang, C., Derrien, M., Levenez, F., Brazeilles, R., Ballal, S. A., Kim, J., et al. (2016). Ecological robustness of the gut microbiota in response to ingestion of transient food-borne microbes. ISME J. 10, 2235–2245. Doi: 10.1038/ismej.2016.13
  • Marteau, P., Guyonnet, D., Lafaye de Micheaux, P., and Gelu, S. (2013). A randomized, double-blind, controlled study and pooled analysis of two identical trials of fermented milk containing probiotic Bifidobacterium lactis CNCM I-2494 in healthy women reporting minor digestive symptoms. Neurogastroenterol. Motil. 25, 331–e252. Doi: 10.1111/nmo.12078
  • Romijn, A. R., Rucklidge, J. J., Kuijer, R. G., and Frampton, C. (2017). A double-blind, randomized, placebo-controlled trial of Lactobacillus helveticus and Bifidobacterium longum for the symptoms of depression. Aust. N. Z. J. Psychiatry 51, 810–821.
  • Voidarou, C., Antoniadou, M., Rozos, G., Tzora, A., Skoufos, I., Varzakas, T., et al. (2020). Fermentative foods: microbiology, biochemistry, potential human health benefits and public health issues. Foods 10:69. Doi: 10.3390/foods10010069
  • Anyogu, A., Olukorede, A., Anumudu, C., Onyeaka, H., Areo, E., Adewale, O., et al. (2021). Microorganisms and food safety risks associated with indigenous fermented foods from Africa. Food Control 129:108227. Doi: 10.1016/j.foodcont.2021.108227

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