Why Does Mozzarella Have No Lactose? Unpacking the Low-Lactose Reality

December 7, 2025 •

2 min read

While many believe mozzarella is completely lactose-free, a 100g serving of fresh mozzarella actually contains around 2-3 grams of lactose. The misconception arises because its specific production process significantly reduces the milk's original sugar, which explains why does mozzarella have no lactose to many consumers who find it easy to digest.

Quick Summary

Mozzarella's low lactose level is due to its unique cheesemaking process. Most of the milk sugar is removed with the whey during curd separation, and starter bacteria ferment the remaining lactose into lactic acid. The 'pasta filata' method further reduces moisture, making the cheese more digestible for many with lactose sensitivity.

Key Points

Low, not zero: Mozzarella is not naturally lactose-free, but its manufacturing process reduces lactose to very low levels.
Whey removal is key: The majority of lactose is water-soluble and is drained away with the whey during curd separation.
Fermentation helps: Lactic acid bacteria in the starter culture ferment residual lactose into lactic acid.
Stretching reduces moisture: The pasta filata stretching method squeezes out more whey, further reducing lactose content.
Most tolerate it: Due to its low lactose level, mozzarella is often well-tolerated by individuals with mild to moderate lactose intolerance.
Aging makes a difference: Fresh mozzarella has more lactose than very aged cheeses like Parmesan, which are nearly lactose-free.

Understanding Lactose in Dairy

Lactose is a sugar naturally found in milk. People with lactose intolerance lack sufficient lactase enzyme to break down this sugar, leading to digestive issues. Lactose content varies among dairy products, particularly cheeses, based on their production and aging. Mozzarella's manufacturing process substantially lowers its lactose, though it's not entirely eliminated.

The Mozzarella-Making Process: A Deeper Look

Mozzarella is a pasta filata cheese, meaning "spun paste" or "stretched curd." This process is key to its low lactose content. It starts with milk, usually cow's milk, though traditional Mozzarella di Bufala uses water buffalo milk, which has slightly less lactose.

Fermentation and Coagulation

Lactic acid bacteria are added to the milk to ferment lactose into lactic acid. Rennet is then added, separating milk into curds and whey.

Whey Separation and Stretching

Most lactose dissolves in the whey, which is drained after cutting the curds. The pasta filata method involves heating and stretching the curds, expelling more lactose-rich whey and contributing to mozzarella's stretchy texture.

The Low-Lactose Effect

These steps result in mozzarella's low lactose concentration. Fresh mozzarella has a small amount, while aged varieties may have less. Most individuals with lactose intolerance can tolerate typical mozzarella servings, often comfortable with up to 12 grams of lactose at once.

Mozzarella vs. Other Cheeses: A Lactose Comparison

Cheese lactose levels depend on aging and moisture. Hard, aged cheeses generally have the least lactose.


Cheese Type	Approximate Lactose Content (per 100g)	Aging Process	Primary Reason for Low Lactose
Fresh Mozzarella	2-3 grams	Short/Unaged	Whey removal, some fermentation
Aged Cheddar	< 0.1 grams	Long (6+ months)	Long fermentation consumes remaining lactose
Parmesan	< 0.1 grams	Long (12+ months)	Extensive aging and fermentation
Swiss (Emmental)	< 0.1 grams	Long (5+ months)	Extensive aging and fermentation
Cottage Cheese	3.5 grams	Unaged	Retains more whey during production
Ricotta	1-5 grams	Unaged	Made from leftover whey, retaining lactose

Conclusion

While not entirely lactose-free, mozzarella's low lactose is due to its production. Whey removal, bacterial fermentation, and the pasta filata process significantly reduce lactose. This makes fresh, soft mozzarella digestible for many with lactose sensitivity. Lactose-free options are available for severe intolerance. Understanding cheesemaking helps consumers make informed choices. For more on dairy and lactose, consult resources like the National Institutes of Health.

Frequently Asked Questions

No, fresh mozzarella is not completely lactose-free, but it is low in lactose. A standard 100g serving contains about 2-3 grams of lactose, which is a very small amount compared to milk.

The process reduces lactose in two main ways: draining the liquid whey, which contains most of the milk's lactose, and fermentation, where starter bacteria consume the remaining lactose, converting it into lactic acid.

Most people with lactose intolerance can consume mozzarella without adverse effects due to its low lactose content. Many can tolerate up to 12 grams of lactose per sitting, and mozzarella typically falls well below that threshold.

The pasta filata method is the process of heating and stretching the mozzarella curd. This action helps to expel more of the lactose-rich whey, further lowering the final lactose content of the cheese.

Yes, generally, the longer a cheese ages, the lower its lactose content becomes. The bacteria continue to ferment the lactose over time, meaning aged mozzarella or low-moisture shredded mozzarella often has less lactose than fresh mozzarella balls.

Buffalo milk naturally contains slightly less lactose than cow's milk. Traditional Mozzarella di Bufala, therefore, starts with a slightly lower lactose base, though the production process is the main factor in lactose reduction.

Yes, some brands produce certified lactose-free mozzarella. This is achieved by adding the lactase enzyme during the manufacturing process to break down the lactose completely.