Foods That Contain L. casei

January 11, 2026 •

4 min read

Over 60% of people consider a healthy immune system a top priority, and certain probiotics play a key role in achieving this goal. A highly researched probiotic, Lactobacillus casei (now reclassified as Lacticaseibacillus casei), is found in a variety of fermented foods and commercial products, offering potential benefits for digestive and immune health.

Quick Summary

A variety of foods contain the probiotic L. casei, including fermented dairy products like certain yogurts and kefirs, as well as vegetables such as sauerkraut and kimchi. Specialized commercial drinks also contain specific, well-researched strains of this beneficial bacteria.

Key Points

Specific Strains: Commercial probiotic drinks like Actimel and Yakult contain unique and well-researched strains of L. casei for targeted health benefits.
Fermented Dairy: Certain yogurts and kefir are excellent sources of L. casei, but you must check the label for 'live and active cultures'.
Raw Fermented Vegetables: Unpasteurized sauerkraut, kimchi, and olives offer L. casei and other probiotics from plant-based sources.
Homemade Fermentation: You can make your own probiotic-rich foods, including yogurt and sauerkraut, to ensure the presence of live cultures.
Strain-Specificity: The health benefits of L. casei depend on the specific strain, with some having more scientific evidence than others for certain applications.
Storage is Crucial: Probiotics are live organisms, so proper storage is essential to maintain their viability and effectiveness.

What is L. casei?

Lactobacillus casei is a beneficial strain of lactic acid bacteria that resides in the human digestive and reproductive tracts. Known for its resilience, it can survive the acidic environment of the stomach to reach the intestines alive, where it can exert its probiotic effects. The health-promoting properties of L. casei are highly strain-specific, meaning that the benefits can vary depending on the particular strain consumed, such as L. casei Shirota (found in Yakult) or L. casei Danone (in Actimel).

Fermented Dairy Products

Many of the most common dietary sources of L. casei are fermented dairy products, which use live bacterial cultures during their production. However, it is important to check product labels, as not all items contain the specific cultures or the necessary live, active bacteria to offer probiotic benefits.

Yogurt

Cultured Yogurt: Some brands of yogurt are explicitly fortified with L. casei. Always look for labels that state “live and active cultures” and list L. casei in the ingredients. Plain, unflavored yogurts are often the best bet, as added sugars can feed less desirable gut bacteria.
DIY Yogurt: For those who prefer to make their own, specific starter cultures and precise fermentation temperatures are required. Recipes for homemade yogurts often include L. casei as a primary culture.

Kefir

Dairy Kefir: This fermented milk drink is made using kefir grains, which are a complex mix of beneficial bacteria and yeasts. Certain kefir strains, particularly those made from dairy, are known to contain L. casei and a wider array of other beneficial microbes than yogurt.
Vegan Kefir: Non-dairy versions, such as cashew kefir, can also be made with a starter culture that includes various Lactobacillus strains.

Fermented Cheeses and Buttermilk

Aged Cheese: L. casei is often the dominant species of non-starter lactic acid bacteria in ripening cheddar cheese. Other fermented cheeses may also contain this probiotic, depending on the production process.
Cultured Buttermilk: Traditional, cultured buttermilk is a byproduct of butter making that contains lactic acid bacteria, including potentially L. casei.

Fermented Vegetable and Plant-Based Foods

Beyond dairy, L. casei and other Lactobacillus species can be found in a variety of fermented plant-based foods.

Sauerkraut

Naturally Fermented Sauerkraut: This finely shredded, fermented cabbage dish is an excellent source of probiotics, including L. casei, when prepared properly. Look for unpasteurized or raw versions, as heat processing kills the beneficial bacteria.
Homemade Sauerkraut: Making sauerkraut at home is a simple process that allows you to control the ingredients and ensure a high concentration of live cultures.

Kimchi

Korean Kimchi: This spicy, fermented vegetable dish, typically made with cabbage, is a rich source of lactic acid bacteria. Different preparations can lead to varying microbial profiles, often including L. casei.

Olives

Sicilian Olives: Naturally fermented Sicilian green olives have been found to contain L. casei as the dominant bacterial species during fermentation.

Sourdough

Sourdough Bread: The starter culture used to make sourdough bread is a mix of wild yeast and lactic acid bacteria, including L. casei. While baking kills the live bacteria, the fermentation process itself predigests certain compounds and can still offer some health benefits.

Miso and Tempeh

Miso: This traditional Japanese seasoning paste, made by fermenting soybeans, contains L. casei and other beneficial bacteria.
Tempeh: An Indonesian soy product made from fermented soybeans, tempeh is a popular probiotic source for vegans.

Specialized Commercial Probiotic Drinks

Several widely available commercial drinks are specifically fortified with targeted strains of L. casei for maximum benefit.

Actimel/DanActive

L. casei Danone® (DN-114001): Produced by Danone, this specific strain is a primary component of their Actimel (or DanActive) yogurt drinks. It is known for its ability to survive gastric transit.

Yakult

L. casei Shirota (LcS): This well-researched strain was discovered by Dr. Mino Shirota in 1930. It is exclusive to the Yakult beverage and is proven to survive the harsh environment of the gut to reach the intestines alive.

A Comparison of L. casei Food Sources

To help you decide which sources to incorporate into your diet, here is a comparison table of different L. casei food options.


Feature	Yogurt (with L. casei)	Sauerkraut (raw)	Kefir	Yakult (LcS)
Type of Food	Fermented Dairy	Fermented Vegetable	Fermented Dairy	Commercial Drink
Availability	Wide	Moderate	Moderate to Wide	Wide
Live Cultures	Yes (check label)	Yes (unpasteurized)	Yes	Yes (specific strain)
Other Nutrients	Calcium, Protein	Vitamin K, C, Fiber	Calcium, Protein	Vitamin D, B6 (added)
Taste Profile	Creamy, Tangy	Tangy, Sour	Tart, Effervescent	Sweet, Milky
Suitability for Vegans	No	Yes	No (Dairy Kefir)	No

Conclusion

While a variety of foods can contain the beneficial probiotic L. casei, it is crucial to remember that not all fermented products are equal. Checking labels for "live and active cultures" and seeking out specific, commercially proven probiotic strains will ensure you are getting a product with a genuine, scientifically-backed probiotic benefit. Incorporating a range of these foods into your diet can be a delicious and effective strategy for promoting gut health and overall well-being. For a deeper understanding of specific probiotic benefits, always consult credible scientific resources.

What to consider when consuming foods with L. casei

Check the Label: Not all fermented foods guarantee live cultures, especially if they have been pasteurized or heat-treated. Always read the ingredient list and product claims.
Variety is Key: The gut microbiome thrives on diversity. Don't rely on a single food source, but instead incorporate a mix of fermented foods into your diet for a broader spectrum of beneficial bacteria.
Storage Matters: Probiotics are live organisms that require proper storage to remain viable. Follow the storage instructions on the product packaging to ensure the bacteria stay alive and active.
Dietary Needs: For individuals with dairy allergies or who follow a vegan diet, plant-based fermented foods like unpasteurized sauerkraut, kimchi, or tempeh are excellent options.

Outbound Link

For more detailed information on probiotic strains and their specific benefits, the Wikipedia page on Lacticaseibacillus casei is a valuable resource.

Frequently Asked Questions

Lactobacillus casei is a specific strain of probiotic bacteria. While it belongs to the larger Lactobacillus family, its unique properties, such as acid resistance, distinguish it from other strains. The health benefits are also often strain-specific, such as the L. casei Shirota strain in Yakult, which has been extensively studied for its specific effects on intestinal health.

No, not all yogurts contain L. casei. The presence of this specific probiotic depends on the starter cultures used by the manufacturer. You should always check the product label for the "live and active cultures" seal and look for L. casei listed in the ingredients.

Yes, high heat, such as pasteurization or cooking, will kill the live probiotic bacteria in fermented foods. For probiotic benefits, you should consume raw, unpasteurized versions of foods like sauerkraut and kimchi. In foods like sourdough bread, the fermentation process contributes to the flavor and texture, but the baking process kills the live bacteria.

Yes, L. casei is available in dietary supplements. These are an alternative to getting the probiotic from food sources. As with food, it is important to check the expiration date and follow the storage directions for the supplement.

While benefits can be strain-specific, studies on various L. casei strains have suggested potential advantages such as alleviating gastrointestinal pathogenic bacterial diseases, reducing antibiotic-associated diarrhea, and possibly inhibiting the growth of Helicobacter pylori.

Yes, the L. casei Shirota strain is unique to the Yakult beverage. The company has performed significant research to confirm its ability to survive gastric acid and reach the intestines alive.

When purchasing products with L. casei, look for labels indicating "live and active cultures." For fermented vegetables like sauerkraut, choose unpasteurized versions from the refrigerated section. In commercial drinks like Yakult or Actimel, the specific strain is clearly stated.