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What to Know About Lactic Acid in Food

Reviewed by Dan Brennan, MD on October 25, 2021

Lactic acid is a natural preservative often found in foods like yogurt, baked goods, and pickled vegetables. Along with making your food last longer, it can boost your health by strengthening your immune system.

Here’s what you need to know about the health benefits of lactic acid and what foods have high amounts of it.

What Is Lactic Acid?

Lactic acid is an organic acid that forms when certain foods go through the process of fermentation. It’s often found in pickled foods, fermented soy products, salami, yogurt, and more. 

Food manufacturers add lactic acid to packaged food products such as bread, desserts, olives, and jams to give them longer shelf lives. Lactic acid is a good preservative because it can kill and suppress bacteria in food.

Lactic acid also helps prevent discoloration and works as a gelling agent and a curing agent.

How Is Lactic Acid Made?

Lactic acid is produced through fermentation, a process where yeasts, mold, fungi, or bacteria break down carbohydrates -- like sugar and starch -- into alcohol, gas, and acids. Fermentation results in food products high in lactic acid.

Fermentation can happen naturally. Yogurt and sourdough, for instance, ferment on their own. But in most cases, food manufacturers use a starter culture to begin the fermentation process.

A manufacturer takes these steps to create fermented foods:

  1. Selects a container to limit oxygen exposure
  2. Adds a brine of water and salt to the container before sealing it
  3. Puts in the food that needs to be fermented, such as cabbage or cucumber

As bacteria break down the sugar in the food, carbon dioxide and lactic acid will form. Meanwhile, the process removes oxygen, and the food becomes more acidic. This promotes the growth of more lactic acid bacteria and suppresses the growth of other microorganisms.

The fermentation process can take anywhere from days to months. The food manufacturer will then take the fermented food out and store it in a cool place to keep it from spoiling.

What Foods Are High in Lactic Acid?

A few types of foods are high in lactic acid. Generally, any food produced through a fermentation process is full of lactic acid bacteria and other beneficial bacteria. These include but are not limited to:

  • Bread and beer
  • Soy products such as tofu and soy milk
  • Cheese
  • Pickled vegetables such as kimchi and sauerkraut
  • Pickled meats such as salami
  • Legumes such as beans and peas.

To get the most out of these foods, avoid cooking them over high heat. This may kill the beneficial bacteria. 

Instead, try adding them as toppings or condiments for cooked food. Fermented foods are delicious and highly varied in texture and flavor. They make an excellent addition to any meal.

Is Lactic Acid Vegan?

Generally, lactic acid is vegan because it’s made from or originates from cereals, legumes, or fermented vegetables. The main exceptions are lactic acid found in fermented meat and dairy products, which are non-vegan.

But some food manufacturers may have used animal sources to produce human-made lactic acid. The only way to find out for certain is to ask the manufacturer directly.

Is Lactic Acid Good for You?

Yes, lactic acid is good for you, even when it’s in the form of a food preservative.

Although many food preservatives are unhealthy, lactic acid preservatives will help protect you from getting sick. It controls the pH, or acidity and alkalinity, to prevent food from spoiling.

Lactic acid also improves your food’s taste. By controlling the acidity, it balances flavors in foods such as olives, cheese, canned fish, desserts, and carbonated drinks.

More importantly, lactic acid can boost the quality of your food’s nutrition. While the lactic acid added to desserts, canned fish, and carbonated drinks is not very healthy, the naturally produced lactic acid in fermented foods such as kimchi and yogurt offers a variety of health benefits by:

  • Strengthening your immune system
  • Helping your body absorb minerals and vitamins
  • Giving your food antioxidant effects
  • Protecting you from vaginal and urinary infections

Some strains of lactic acid bacteria found in food are probiotics, such as those belonging to the genus Lactobacillus. This means many foods high in lactic acid have probiotic qualities and can boost your gut health.

Lactic acid can also protect you from constipation and other gastrointestinal issues.

Show Sources

SOURCES:

FEMS Microbiology Reviews: “Flavour formation by lactic acid bacteria and biochemical flavour profiling of cheese products.”

Food Research International: “Vegan probiotic products: A modern tendency or the newest challenge in functional foods.”

Food Science and Human Wellness: “Fermentation-enabled wellness foods: A fresh perspective.”

Frontiers in Microbiology: “Extractive Fermentation of Lactic Acid in Lactic Acid Bacteria Cultivation: A Review,” “Fermented Foods as a Dietary Source of Live Organisms.”

Journal of Bacteriology & Mycology: Open Access: “Lactic acid bacteria: their applications in foods.”

Microorganisms: “The Role of Yeasts in Fermentation Processes.”

National Research Council (US) Panel on the Applications of Biotechnology to Traditional Fermented Foods. Applications of Biotechnology to Fermented Foods: Report of an Ad Hoc Panel of the Board on Science and Technology for International Development, National Academies Press (US), 1992.

Nature Communications: “Large-scale genome-wide analysis links lactic acid bacteria from food with the gut microbiome.”

Nutrition and Dietary Supplements: “Effect of Lactic Acid Bacteria-Fermented Soy Milk Extract (LEX) on Urinary 3-Indoxyl Sulfate in Japanese Healthy Adult Women: An Open-Label Pilot Study.”

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