Surviving the stomach

In order to reach the intestines alive, probiotics must be able to survive the harsh conditions in the stomach. Strong acid and digestive enzymes in the stomach are part of the normal digestive process, but they also kill many microorganisms that come into your body with your food.

Manufacturers can use special production processes and formulations to make a probiotic more tolerant to the stomach’s inhospitable environment.^1,2 However, each bacterial strain of probiotic already has a naturally inbuilt level of tolerance to acidic conditions, which is often an important reason why a particular strain is used as a probiotic.^3,4,5 For example, lactobacilli are usually relatively tolerant of acid conditions because they already create an acidic environment as a consequence of their metabolism, so they are used to this type of environment. Most bifidobacteria on the other hand are more sensitive to the damaging effects of acid.⁶ But it’s not quite as simple as that! The Bifidobacterium, BB-12^® strain has been shown to be tolerant of acid conditions.^7,8 An experiment was done using an artificial gut that simulates passage of a probiotic through gastric acid and intestinal bile. In that experiment, a normal dose of Bifidobacterium, BB-12^® was ‘swallowed’ and passed through the artificial gut. After passing through the gastric acid and bile, 60%–80% of BB-12^® was still alive.⁹ 

At Chr. Hansen, our probiotic strains are carefully selected and tested to ensure their survival through the digestive system. Each strain is naturally resistant to stomach acid and bile for a successful journey through the intestines. 


BB-12^® is a trademark of Chr. Hansen A/S.

The article is provided for informational purposes regarding probiotics and is not meant to suggest that any substance referenced in the article is intended to diagnose, cure, mitigate, treat, or prevent any disease.

Reference list

1. Van Bokhorst-van De Veen H, et al. Modulation of Lactobacillus plantarum Gastrointestinal Robustness by Fermentation Conditions Enables Identification of Bacterial Robustness Markers. PLoS One. 2012;7(7):e39053. (PubMed)
2. Papadimitriou K, et al. Stress Physiology of Lactic Acid Bacteria. Microbiol Mol Biol Rev. 2016;80(3):837–890. (PubMed)
3. Collado MC, Sanz Y. Method for direct selection of potentially probiotic Bifidobacterium strains from human feces based on their acid-adaptation ability. J Microbiol Methods. 2006;66(3):560–563. (PubMed)
4. Reis NA, et al. Probiotic properties of lactic acid bacteria isolated from human milk. J Appl Microbiol. 2016;121(3):811–820. (PubMed)
5. Dunne C, et al. In vitro selection criteria for probiotic bacteria of human origin: Correlation with in vivo findings. Am J Clin Nutr. 2001;73(2 SUPPL.):386S–392S. (PubMed)
6. Andriantsoanirina V, et al. Tolerance of Bifidobacterium human isolates to bile, acid and oxygen. Anaerobe. 2013;21:39–42. (PubMed)
7. Vernazza CL, et al. Carbohydrate preference, acid tolerance and bile tolerance in five strains of Bifidobacterium. J Appl Microbiol. 2006;100(4):846–853. (PubMed)
8. Matsumoto M, et al. H+-ATPase activity in Bifidobacterium with special reference to acid tolerance. Int J Food Microbiol. 2004;93(1):109–113. (PubMed)
9. Jungersen M, et al. The Science behind the Probiotic Strain Bifidobacterium animalis subsp. lactis BB-12^®. Microorganisms. 2014;2(2):92–110. (PubMed)