Does Greek Yogurt Have Lactobacillus Bulgaricus?

November 26, 2025 •

3 min read

According to the U.S. Food and Drug Administration (FDA) regulations, both regular and Greek yogurt must contain the starter cultures Streptococcus thermophilus and Lactobacillus bulgaricus. These two specific bacteria are crucial for the fermentation process that turns milk into yogurt, meaning Greek yogurt indeed contains Lactobacillus bulgaricus.

Quick Summary

Greek yogurt is made using the same starter bacteria as regular yogurt, including Lactobacillus bulgaricus and Streptococcus thermophilus. The key difference lies in the straining process that removes whey, resulting in a thicker, higher-protein final product.

Key Points

Mandatory Ingredient: All traditional yogurt, including Greek, must be made with Lactobacillus bulgaricus and Streptococcus thermophilus to be called yogurt.
Shared Cultures: Greek yogurt and regular yogurt start with the same two live bacterial cultures for fermentation.
Straining is the Key: The primary difference is that Greek yogurt is strained to remove liquid whey, which concentrates the remaining milk solids.
Concentrated Nutrients: The straining process results in Greek yogurt having significantly more protein and a thicker texture than regular yogurt.
Live and Active: The probiotics, including Lactobacillus bulgaricus, are not removed during straining, making Greek yogurt a great source of beneficial bacteria.
Potential for More Probiotics: Some brands may add extra probiotic strains to Greek yogurt after fermentation.
Digestive Benefits: Due to its live and active cultures, Greek yogurt aids in digestion and promotes a healthy gut microbiome.

Greek and Regular Yogurt: Same Foundation, Different Finish

At its core, all traditional yogurt production relies on the same two primary bacterial strains: Lactobacillus bulgaricus and Streptococcus thermophilus. This pair works in a symbiotic relationship to ferment lactose, the natural sugar in milk, into lactic acid. This process is what gives yogurt its characteristic tangy flavor and thick, creamy texture.

The Fermentation Process Explained

When milk is heated and cooled, these cultures are introduced to initiate fermentation.

The Streptococcus thermophilus bacteria begin the process by lowering the pH of the milk.
This creates an ideal, slightly acidic environment for the Lactobacillus bulgaricus to thrive.
As the Lactobacillus bulgaricus multiplies, it further lowers the pH and produces acetaldehyde, a key component of yogurt's aroma and flavor.
The lactic acid produced by both bacteria causes the milk proteins to coagulate, resulting in the yogurt's thick consistency.

The Straining Process: The Making of Greek Yogurt

So, if the bacteria are the same, what makes Greek yogurt different from regular yogurt? The answer lies in the production method after the initial fermentation.

Regular Yogurt: After the fermentation is complete, the process stops, and the yogurt is packaged.
Greek Yogurt: The newly fermented yogurt undergoes an additional step called straining. This involves removing the liquid whey, resulting in a significantly thicker, denser, and tangier product. The straining process also concentrates the yogurt, leading to a higher protein content and lower sugar count per serving compared to its regular counterpart.

This is why some brands may be labeled "Greek-style" if they use thickening agents like gelatin or starches instead of the traditional straining method. Authentic Greek yogurt relies solely on the straining to achieve its rich texture.

Comparison Table: Greek vs. Regular Yogurt


Feature	Greek Yogurt	Regular Yogurt
Starter Cultures	Contains Lactobacillus bulgaricus and Streptococcus thermophilus	Contains Lactobacillus bulgaricus and Streptococcus thermophilus
Production Method	Fermented milk is strained to remove whey	Fermented milk is typically not strained
Texture	Thicker, denser, and creamier	Thinner consistency
Protein Content	Higher (often double or more)	Lower
Sugar Content	Lower (less lactose due to straining)	Higher (more lactose)
Tanginess	More tangy and concentrated	Less tangy, often milder in flavor

The Probiotic Presence in Both Yogurt Types

Both Greek and regular yogurt are excellent sources of probiotics, as long as they contain "live and active cultures". The straining process does not eliminate the beneficial bacteria. In fact, some research suggests that Greek yogurt may contain an even higher concentration of probiotics due to its density. Many Greek yogurt brands also add additional probiotic strains like Lactobacillus acidophilus or Bifidobacterium lactis to enhance their health benefits.

Conclusion

In conclusion, Greek yogurt does have Lactobacillus bulgaricus, along with Streptococcus thermophilus, as these are the two mandatory starter cultures for any product to be legally classified as yogurt. The fundamental difference in Greek yogurt is not the bacteria it contains, but rather the post-fermentation straining process. This process is responsible for Greek yogurt's distinctively thick texture, high protein content, and lower sugar level compared to regular yogurt, while still providing the gut health benefits associated with its live and active cultures. Whether you prefer regular or Greek, checking for the "Live & Active Cultures" seal on the label is the best way to ensure you are getting a product rich in these beneficial microbes.

Authoritative Outbound Link for further reading

Frequently Asked Questions

The main difference is that Greek yogurt is strained to remove the liquid whey after fermentation, while regular yogurt is not. This process makes Greek yogurt thicker, tangier, and higher in protein, with less sugar and carbohydrates.

No, it is not necessary. FDA regulations state that any product labeled as yogurt must contain both Lactobacillus bulgaricus and Streptococcus thermophilus. However, checking for a "live and active cultures" seal confirms the bacteria are still viable.

No, the straining process primarily removes whey, not the bacteria. As a result, Greek yogurt often has a high concentration of probiotics, and some brands even add more strains to further enhance its health benefits.

No, they are different. Authentic Greek yogurt is naturally thickened through straining, whereas Greek-style yogurts often use thickening agents and additives to mimic the texture.

Yes. The fermentation process breaks down some of the lactose, making yogurt easier to digest for many people with lactose intolerance. Greek yogurt, with its lower lactose content due to straining, can be an even better option.

Lactobacillus bulgaricus, along with other probiotics in yogurt, can promote a healthy gut microbiome, aid in digestion, and support the immune system.

Yes. You can purchase Greek yogurt starter cultures containing Lactobacillus bulgaricus and Streptococcus thermophilus and use a straining method to create homemade Greek yogurt.