Probiotics Fermented Food: Their Beneficial Effects

Introduction and Historical Background

Probiotics are living microorganisms that supply beneficial properties to individuals when consumed in sufficient doses. These bacteria, known as good bacteria, can be found in the human gastrointestinal tract and provide anti-inflammatory, anti-cancer, and immunity-boosting functions (Kaur et al., 2020) (Figure 1). Over the last decade, the global market for probiotics has experienced significant growth, encompassing foods, supplements, and pharmaceutical products, and it is expected to reach US$ 85.4 billion by 2027 with a 8.1% growth percentage (Guarner et al., 2023). Consumers have become increasingly mindful of their dietary choices and are embracing healthier lifestyles by including nutritious foods in their daily diets to fulfill their nutrient needs (Aggarwal et al., 2023).

Probiotics have been used before the discovery of the microbes. Fermented milk products were first prepared in Egyptian hieroglyphs and by Tibetan nomads. By the 19th century, the health benefits of fermented milk consumption were recognized; however, the underlying mechanisms remained unknown.  Afterward, in 1906, Probiotics (Bifidobacterium) were isolated from infant stool and claimed to suppress pathogenic bacteria in the gut. In 1932, the first investigation confirmed the effect of L. acidophilus in improving constipation and mental disease.

During the 1930s, yogurt was identified as the best probiotic vehicle, and screening experiments were conducted to find out the most promising probiotics in terms of beneficial health effects and final product quality. Between 1950- 1980, probiotics were isolated from different natural sources, and their mechanism in colonizing the colon was studied (McFarland., 2015).

The term “probiotic” was initially used in 1965,  to define the compounds that are released by bacteria and enhance the growth of other organisms, and it means “for life”. In 2001, the Food and Agriculture Organization described probiotics as “live microorganisms which, when administered in adequate amounts, confer a health benefit on the host” (McFarland., 2015).

Figure 1: Probiotics Health Benefits (Nateghi & Hosseiny, 2025).

Key Traits of Probiotics

Safety and functioning properties must be evaluated before a bacterial strain can be recognized as a probiotic. This involves the stability of genes, acid and bile sensitivity, bile salt hydrolase activity, adherence to the intestinal lining, anti-genotoxic characteristics, non-pathogenic features, lactic acid production, resilience to rigorous processing environments, and a shorter generation time (Sarita et al., 2025; Nateghi & Hosseiny, 2025). They include lactic acid bacteria of the genera Lactobacillus, Streptococcus, Leuconostoc, and Bifidobacterium (Nateghi & Hosseiny, 2025). The Lactobacillus and Bifidobacterium genera are the most commonly utilized strains, comprising the largest category within probiotics (Aggarwal et al., 2023). In scientific literature, populations of 10⁶-10⁷ CFU/g in the final product are established as therapeutic quantities of probiotic cultures in processed foods.

Probiotics function by strengthening the barrier of epithelial cells, enhancing microbial adherence to the gut tissue, inhibiting pathogen adhesion, modulating the immune system's response, and producing biochemicals that can inhibit the proliferation of pathogenic microorganisms. These antimicrobial substances are commonly bacteriocins. They also release short-chain fatty acids (SCFAs), hydrogen peroxide (H₂O₂), and diacetyl. These materials alter the intestinal microflora, resulting in positive health benefits. Most of the Bifidobacteria and Lactobacilli are capable of manufacturing these bacteriocins (Sarita et al., 2025). Furthermore, non-viable probiotics could also produce therapeutic benefits on the host (Nateghi & Hosseiny, 2025).

Potential Health Advantages of Probiotics

Gastrointestinal Effect

According to metadata analysis, probiotics  were found to have a significant positive impact on some gastrointestinal diseases, including pouchitis, infectious diarrhea, irritable bowel syndrome, helicobacter pylori, clostridium difficile disease, and antibiotic associated diarrhea (Wu et al., 2024). In terms of lactose intolerance, probiotics help in reducing its symptoms such as abdominal pain, diarrhea, and flatulence (Ahn., 2023).  It is important to note that probiotics species and gastrointestinal disease type are important factors for alleviating or curing the digestive disorder (Ritchie & Romanuk, 2012). Therefore, choosing the appropriate probiotic strain is vital, for instance, Bifidobacterium and Lactobacillus are widely used and recommended for Irritable Bowel Syndrome (Wu et al., 2024). 

Metabolic Effect

In addition to gastrointestinal effects, probiotic intake was useful in controlling blood glucose, body mass index, and inflammation-related C-reactive protein in overweight or obese adolescents (Duan et al., 2024). 

Moreover, Probiotics consumption reduces the level of fat, improves oxidative stress and inflammation, decreases liver damage, as well as alleviating hyperlipidemia due to the production of short-chain fatty acid substances in the body involving butyrate, propionate, and acetate (Yao et al., 2024).

Mechanisms Effect

Probiotics can reduce pathogen adhesion by limiting the availability of binding sites on the intestinal epithelium, thereby decreasing host–pathogen interactions. They also release beneficial by-products such as short-chain fatty acids, organic acids, carbon dioxide, hydrogen peroxide, acetoin, acetaldehyde, diacetyl, and bacteriocins, which boost the host’s health (Figure 2). Bacteriocins have antimicrobial characteristics against pathogenic species, involving Staphylococcus, Clostridium, Listeria, and Bacillus (Nateghi & Hosseiny, 2025). Further, Lactobacillus species was found to modulate inflammation in the healthy elderly via immune system adjustment (Ervina et al., 2024).

Figure 2: Probiotics Mechanism (Bermúdez-Humarán et al.,2024)

Maternal/Infant Health Effect

Probiotic consumption is associated with strengthening the immune systems of pregnant women and babies. Particularly, Lacticaseibacillus rhamnosus Rosell^®-11 and Bifidobacterium bifidum HA-132 supplementation throughout the third trimester of pregnancy and breastfeeding has shown immunological benefits (Binda et al., 2025). Additionally, a 1-3 months probiotics therapy demonstrated a significant impact in treating bacterial vaginitis disease in women (Lu & Yl, 2022).

Micronutrient Effect

In addition to these health benefits, probiotics also provide vitamins to their host (Bermúdez-Humarán et al.,2024).  Lactiplantibacillus plantarum 299v, reported to improve iron absorption (Vonderheid et al., 2019). Notably, the minimum recommended dosage of probiotic culture to achieve its therapeutic effect is  10⁶-10⁷ CFU/g in the final product, which is equivalent to 10⁸–10⁹ CFU when 100 g or 100 mL of food is consumed daily, thus contributing to human health (Cruz et al., 2009).

Dietary Sources of Probiotics

Probiotics are typically offered in various types,  as described in Figure (3), such as capsules, powder sachets, and pills. However, it is highly recommended to consume it via functional foods such as traditional dairy products (buttermilk, curd, yoghurt, cream, ice cream, and cheese) as well as non-dairy products, including fermented cabbage, fruits and fruit juices, cereals, meat, and meat products (Aggarwal et al., 2023). In this context numerous aspects establish the consumers’ patterning, such as the survival of probiotics in the product at the consumption time, the transportation throughout the digestive tract, sensorial characteristics of the end product,  consumers' natural perceptions of foods compared to medications, as well as the financial cost of nutrition. Foods have the dual purpose of fulfilling desire and providing pleasure, whilst supplements deliver a concentrated dose of probiotics for a particular need or overall wellness. 

Figure 3: Some Probiotic Dietary Sources (Bodke & Jogdand., 2022).

Food products exhibit significantly greater potential for variation and advancement than medicine supplements, and the incorporation of probiotics into these products supports substantial development in both product and market domains (Meybodi et al., 2017).

In general, most utilized probiotics originate either from fermented foods or from the microbial colony in the healthy human body. Simultaneously, they were used in the production for ages and are recognised as safe (Guarner et al., 2023). 

Fermented foods and drinks from animal and plant origins are crucial nourishments in human diets. These foods are rich in lactic acid bacteria (LAB) that propagate throughout fermentation, in addition to natural components, such as organic acids, ethanol, or antimicrobial compounds with spoilage organisms and pathogenic bacteria inhibition properties. Moreover, these bacteria are well-adapted to the spontaneous fermentation process with human health benefits which are presented in Figure (4), in particular in the gastrointestinal tract (Soemarie et al., 2021).

Figure 4: The Impact of Probiotic Fermented Foods on The Gut and Brain Health (Magalhães et al., 2025).

In this sense, yogurt is a healthful, probiotic-rich fermented dairy product that is consumed all over the world. It is rich in bio-accessible calcium and essential amino acids (Aggarwal et al., 2023). Yoghurt consumption improves lactose intolerance, enhances the immune system and gastrointestinal function (Weerathilake et al., 2014).

Sauerkraut is a fermented cabbage. It is designated as a superfood mostly due to its probiotic presence, along with the fermentation process that improves the bioavailability of its nutrients compared with its raw form. This includes all the vitamins, minerals, and phytonutrients present in cabbage (Orgeron et al., 2016).

Kimchi is a Korean traditional fermented vegetable. It is processed by combining chinese cabbage, onions, radishes, chili powder, and garlic in addition to several other foods, for instance, carrots, apples, pears, or shrimp. The food consists of various bacterial groups, mainly lactic acid bacteria Lactobacillus, Leuconostoc, and Weissella ( Soemarie et al., 2021).

Health Functionality of kimchi includes anticancer, antiobesity, anticonstipation, colorectal health promotion, probiotic properties, cholesterol reduction, fibrolytic effect, antioxidative and antiaging properties, brain health promotion, immune promotion, and skin health promotion (Park et al., 2014).

Kefir is one of the most significant dairy products (Tomar et al., 2017). It is manufactured through the fermentation of milk using kefir grains as illustrated in Figure (5), or mother cultures derived from these grains. Kefir grains are made up of a complicated combination including several species of Lactobacilli, Lactococci, Leuconostocs, and acetobacteria, as well as yeasts equivalent to probiotic bacteria and yeast included in yogurt. 

Fermentation byproducts such as lactic acid, acetic acid, CO2, ethyl alcohol, and aromatic compounds supply kefir with unique sensorial properties. Furthermore, kefir delivers readily digested complete proteins as well as vitamins, minerals, and vital amino acids that are crucial for the body's maintenance and recovery processes (Otles & Cagindi., 2003).

Figure 5: Kefire Grain (Otles & Cagindi., 2003).

Novel Probiotic Product

Due to the growing popularity of probiotic food, scientists are investigating the possibilities of incorporating probiotics into various foods and drinks. This led to the development of other food products, including probiotic cheese.

Researchers found that cheese provides a suitable probiotic carrier. Because of its greater pH, it acts as a buffer to prevent the gastrointestinal tract's acidic environment, creating a more favorable setting for probiotic survival during digestive tract transit. Additionally, cheese's dense matrix and high fat content may provide extra protection (Cruz et al., 2009). Further, they produce flavors and aromas and significantly speed the cheese's maturation process through their proteolytic and lipolytic activities, which benefits the industry economically (Kongo, 2013). 

Soy drink is a rich source of protein, characterized by low fat content, absence of lactose and cholesterol, and contains a high amount of bioactive compounds;  Soy is a source of isoflavones, substances categorized as phytoestrogens associated with beneficial health effects, Specifically, when fermented with aglycone-producing bacterial strains such as Lacticaseibacillus  rhamnosus GG and Lacticaseibacillus rhamnosus INIA P344, the advantageous benefits involve decreasing the risk of osteoporosis, hypercholesterolemia, obesity, carcinogenesis, and tumor propagation Figure (6) (Bastida et al., 2023).

Figure 6: Health Benefits of Fermented Soy Drink (Hassan et al., 2023).

Probiotic fermented egg white beverage was identified as an appropriate probiotic carrier that is high in functional protein like ovalbumin, ovomucoid, ovoflavoprotein, and lysozyme, and low in cholesterol and fat  (Mourad et al., 2025).

Role of Probiotics in Fermentation

Probiotics from fermented food are safe. It is also rich in nutritional components beneficial for children, adults, and the elderly, such as prebiotics, which are non-digestible carbohydrates that promote the growth of probiotics. Fermented foods also contain postbiotics that have an impact on the microbiota, inflammation, and gut physiology (Pyo et al., 2024). 

The International Scientific Association of Probiotics and Prebiotics (ISAPP) describes postbiotics as combinations of non-living bacteria and their components that have health advantages for the host. These bioactive substances may include small molecules, like hydrogen peroxide, or larger ones, such as bacteriocins. Resulting from microbial metabolic processes in the gut, influencing gut health directly or indirectly through the degradation of prebiotics. Branched protein residues, phenolics, short-chain fatty acids, hydrogen sulfide, and indolic compounds are examples of postbiotics that are produced in the gut after fermented food consumption (Hamdi et al., 2025).

Probiotic fermentation may enhance polyphenol bioavailability by 30–50 % in both dairy and plant-based food structures (Sayın & Alkan, 2015). Lactiplantibacillus plantarum, Lacticaseibacillus rhamnosus, and Bifidobacterium longum have demonstrated the most stable capacity to convert polyphenols, flavonoids, and plant polysaccharides into more accessible compounds. Polyphenols have been documented to confer numerous beneficial health effects, including cardiovascular health, cancer prevention, metabolic health, neurological protection, and gastrointestinal health. Considering that phytochemicals have restricted accessibility to cells, with only limited quantities able to attain systemic circulation for biological functions. Low solubility, fast digestion, and inadequate permeability hinder phytochemicals from achieving therapeutic concentrations. Fermentation predominantly increases antioxidant activity, anti-inflammatory metabolites such as short-chain fatty acids, and the extraction efficiency of polysaccharides, thus expanding the range of bioactivities (Kanimozhi & Sukumar, 2025).

Conclusion

Probiotics are valuable microorganisms that provide health advantages to the host when consumed in specific amounts. They are present in a variety of foods, including cheese, yogurt, pickles, kimchi, sauerkraut, and kefir, along with many innovative probiotic beverages such as egg white and soy drinks. Probiotics are effective in treating diseases such as lactose intolerance, as well as promoting the immune system and inhibiting the growth of harmful pathogens in the gut. Lactobacillus and Bifidobacterium genera are among the most commonly used strains. It is advisable to obtain probiotics from fermented foods instead of supplements or tablets, unless you have medical conditions. Probiotic fermentation not only benefits health through fermentation by products, postbiotics, and other nutritional content in food matrices, but also increases the bioavailability of certain nutrients and biological compounds.

Bibliographical References

Aggarwal, D., Yadav, U., Singh, P., Arora, B., & Khurana, S. (2023). Probiotic foods. In Wani, S. A. Elshikh, M. S.  Al-Wahaibi, M. S. & Naik, H. R. (Eds.), Functional foods (pp. 222–247). CRC Press. https://doi.org/10.1201/9781003315100

Ahn, S.-I., Kim, M. S., Park, D. G., Han, B. K., & Kim, Y. J. (2023). Effects of probiotics administration on lactose intolerance in adulthood: A meta-analysis. Journal of Dairy Science, 106(7), 4489–4501. https://doi.org/10.3168/jds.2022-22762

Bastida, A. R. del la, Peirotén, Á., Langa, S., Rodríguez-Mínguez, E., Curiel, J. A., Arqués, J. L., & Landete, J. M. (2023). Fermented soy beverages as vehicle of probiotic lactobacilli strains and source of bioactive isoflavones: A potential double functional effect. Heliyon, 9(4), 1-8. https://doi.org/10.1016/j.heliyon.2023.e14991

Bermúdez-Humarán, L. G., Chassaing, B., & Langella, P. (2024). Exploring the interaction and impact of probiotic and commensal bacteria on vitamins, minerals and short chain fatty acids metabolism. Microbial Cell Factories, 23(1), 1-11. https://doi.org/10.1186/s12934-024-02449-3

Binda, S., Chow-Shi-Yée, M., El Salti, S., Auclair-Ouellet, N., Oula, M.-L., Carton, T., Leuillet, S., Tomassi, D., Hemmings, R., & Kadoch, I.-J. (2025). The Effect of Probiotics on Health in Pregnancy and Infants: A Randomized, Double-Blind, Placebo-Controlled Trial. Nutrients, 17(11), 1-26. https://doi.org/10.3390/nu17111825

Cruz, A. G. da, Buriti, F. C. A., Souza, C. H. B. de, Faria, J. A. F., & Saad, S. M. I. (2025). Probiotic cheese: Health benefits, technological and stability aspects. Trends in Food Science & Technology, 20(8), 344–354. https://doi.org/10.1016/j.tifs.2009.05.001

Duan, Y., Wang, L., Ma, Y., Ning, L., & Zhang, X. (2024). A meta-analysis of the therapeutic effect of probiotic intervention in obese or overweight adolescents. Frontiers in Endocrinology, 15, 1-15. https://doi.org/10.3389/fendo.2024.1335810

Ervina, W. F., Madyawati, S. P., Saputro, I. D., Safari, D., Putri, R. E., & Zulqaida, S. (2024). A Meta-analysis of the Effect of Probiotic Lactobacillus sp. As Immunomodulating Inflammatory Responses. Medeniyet Medical Journal, 39(2), 122-131. https://doi.org/10.4274/MMJ.galenos.2024.53822

Guarner, F., Sanders, M. E., Szajewska, H., Cohen, H., Eliakim, R., Herrera-deGuise, C., Karakan, T., Merenstein, D., Piscoya, A., Ramakrishna, B., Salminen, S., & Melberg, J. (2023). World Gastroenterology Organisation Global Guidelines: Probiotics and Prebiotics. Journal of Clinical Gastroenterology, 58(6), 533–553. https://doi.org/10.1097/MCG.0000000000002002

Hamdi, A., Lloyd, C., Eri, R., Van, T. T. H., Hamdi, A., Lloyd, C., Eri, R., & Van, T. T. H. (2025). Postbiotics: A Promising Approach to Combat Age-Related Diseases. Life, 15(8), 1-32. https://doi.org/10.3390/life15081190

Kanimozhi, N. V., & Sukumar, M. (2025). Harnessing probiotic fermentation to enhance the bioavailability and health impact of dietary phytochemicals. Food Wellness, 1(1), 1-22. https://doi.org/10.1016/j.foodw.2025.100018  

Kaur, S., Kaur, R., SWATI, S., Joshi, M., Joshi, S. M., & Rani. N.  (2020). Sources and Selection Criteria of Probiotics. In Goel, G.,& Kumar, A., (Eds.),  Advances in Probiotics as Sustainable Food and Medicine, Microorganisms for Sustainability (pp. 222–247). Springer Nature Singapore Pte Ltd. https://doi.org/10.1007/978-981-15-6795-7_2

Kongo, J. M. (2013). Lactic Acid Bacteria as Starter-Cultures for Cheese Processing: Past, Present and Future Developments. In Kongo, J. M. (ED), Lactic Acid Bacteria—R & D for Food, Health and Livestock Purposes (pp 1-672).InTech. https://doi.org/10.5772/55937

Liu, H. F., & YI, N. (n.d.). A systematic review and meta-analysis on the efficacy of probiotics for bacterial vaginosis. European Review for Medical and Pharmacological Sciences, 26, 90–98.

McFarland, L. V. (2015). From yaks to yogurt: The history, development, and current use of probiotics. Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America, 60 (2), 85-90. https://doi.org/10.1093/cid/civ054

Meybodi, N. M., Mortazavian, A. M., Sohrabvandi, S., Cruz, A. G. da, & Mohammadi, R. (n.d.). Probiotic Supplements and Food Products: Comparison for Different Targets. Applied Food Biotechnology, 4(3), 123–132. http://dx.doi.org/10.22037/afb.v4i3.16420

Mourad, R., Aljanabi, I., Csehi, B., Hidas, K., Kókai, Z., Friedrich, L., Németh, C., Gupta, V. K., Gábor, S., Alpár, B., Nguyen, Q. D., & Bujna, E. (2025). Simultaneous blending and fermentation of ToTu^TM an egg-white drink with different fruit juices and probiotic lactic acid bacteria. Food and Bioproducts Processing, 150, 198–206. https://doi.org/10.1016/j.fbp.2025.01.008

Nateghi, L., & Hosseiny, M. (2025). Probiotics in the Food Industry from Production to Food Products and Their Impact on Human Health. Iranian Journal of Chemistry and Chemical Engineering, Online First, 44(2), 447-468. https://doi.org/10.30492/ijcce.2025.2034093.6673

Orgeron, R., Corbin, A., & Scott, B. (2016). Sauerkraut: A Probiotic Superfood. Functional Foods in Health and Disease, 8(6), 536–543.

Otles, S., & Cagindi, Ö. (2003). Kefir: A Probiotic Dairy-Composition, Nutritional and Therapeutic Aspects. Pakistan Journal of Nutrition, 2(2), 54–59. https://doi.org/10.3923/pjn.2003.54.59

Park, K.Y., Jeong, J.K., Lee, Y.E., & Daily, J.W. (2014). Health Benefits of Kimchi (Korean Fermented Vegetables) as a Probiotic Food. Journal of Medicinal Food, 17(1), 6–20. https://doi.org/10.1089/jmf.2013.3083

Pyo, Y., Kwon, K. H., & Jung, Y. J. (2024). Probiotic Functions in Fermented Foods: Anti-Viral, Immunomodulatory, and Anti-Cancer Benefits. Foods, 13(15), 1-18. https://doi.org/10.3390/foods13152386

Ritchie, M. L., & Romanuk, T. N. (2012). A Meta-Analysis of Probiotic Efficacy for Gastrointestinal Diseases. PLoS ONE, 7(4), 1-11. https://doi.org/10.1371/journal.pone.0034938

Sarita, B., Samadhan, D., Hassan, M. Z., & Kovaleva, E. G. (2025). A comprehensive review of probiotics and human health-current prospective and applications. Frontiers in Microbiology, 15, 1-14. https://doi.org/10.3389/fmicb.2024.1487641

Sayın, F. K., & Alkan, S. B. (2015). The Effect of Pickling on Total Phenolic Contents and Antioxidant Activity of 10 Vegetables. Journal of Food and Health Science, 1(3), 135–141. https://doi.org/10.3153/JFHS15013

Soemarie, Y. B., Milanda, T., & Barliana, M. (2021). Fermented Foods as Probiotics: A Review. Journal of Advanced Pharmaceutical Technology Amp Research, 12(4), 335-339. https://doi.org/10.4103/japtr.japtr_116_21

Tomar, O., Çağlar, A., & Akarca, G. (2017). Kefir and Its Importance For Health. Afyon Kocatepe University Journal of Sciences and Engineering, 17(2), 834–853. https://doi.org/10.5578/fmbd.57533

Vonderheid, S. C., Tussing-Humphreys, L., Park, C., Pauls, H., OjiNjideka Hemphill, N., LaBomascus, B., McLeod, A., & Koenig, M. D. (2019). A Systematic Review and Meta-Analysis on the Effects of Probiotic Species on Iron Absorption and Iron Status. Nutrients, 11(12), 2938. https://doi.org/10.3390/nu11122938

Weerathilake, W., Dissanayake, D., Ruwanmali, J., & Munasinghe, M. (2014). The evolution, processing, varieties and health benefits of yogurt. International Journal of Scientific and Research Publications, 4(4),1-9.

Wu, Y., Li, Y., Zheng, Q., & Li, L. (2024). The Efficacy of Probiotics, Prebiotics, Synbiotics, and Fecal Microbiota Transplantation in Irritable Bowel Syndrome: A Systematic Review and Network Meta-Analysis. Nutrients, 16(13), 2114. https://doi.org/10.3390/nu16132114

Yao, Y., Hong, Q., Ding, S., Cui, J., Li, W., Zhang, J., Sun, Y., Yu, Y., Yu, M., Mi, L., Wang, Y., Jiang, J., & Hu, Y. (2024). Meta-analysis of the effects of probiotics on hyperlipidemia. Current Research in Food Science, 9, 1-12. https://doi.org/10.1016/j.crfs.2024.100885

Visual References

Cover image: Leila Divine (2019): Different types of probiotics, including Lactobacillus, and Bifidobacterium in circular shape. https://www.shutterstock.com/es/image-vector/vector-probiotics-circular-shape-bifidobacterium-lactobacillus-1453189379 

Figure1: Nateghi, L., & Hosseiny, M. (2025). Probiotics health benefits. Iranian Journal of Chemistry and Chemical Engineering, Online First. https://doi.org/10.30492/ijcce.2025.2034093.6673

Figure 2: Bermúdez-Humarán, L. G., Chassaing, B., & Langella, P. (2024). Probiotics mechanism. Microbial Cell Factories, 23(1), 172. https://doi.org/10.1186/s12934-024-02449-3

Figure 3: Magalhães, K. T., Silva, R. N. A. da, Borges, A. S., Siqueira, A. E. B., Puerari, C., Bento, J. A. C., Magalhães, K. T., Silva, R. N. A. da, Borges, A. S., Siqueira, A. E. B., Puerari, C., & Bento, J. A. C. (2025). The impact of probiotic fermented foods on gut and brain health. Fermentation, 11(9). https://doi.org/10.3390/fermentation11090537

Figure 4: Bodke, H., & Jogdand, S. (2022). Some probiotic dietary sources. Cureus. https://doi.org/10.7759/cureus.31313

Figure 5: Otles, S., & Cagindi, Ö. (2003). Kefir grain. Pakistan Journal of Nutrition, 2(2), 54–59. https://doi.org/10.3923/pjn.2003.54.59

Figure 6: Hasan, M., Arpitha, S. R., Das, C., Laishram, R., Sasi, M., Kumar, S., Maheshwari, C., Krishnan, V., Kumari, S., Lorenzo, J. M., Kumar, M., Sachdev, A., & Dahuja, A. (2023). Research trends and approaches for the nutritional and bio-functionality enhancement of fermented soymilk. Journal of Functional Foods, 107, 105698. https://doi.org/10.1016/j.jff.2023.105698