Lactic acid is a byproduct of the bacterial fermentation of sugar. Lactic acid is often vegan, but this is not always the case, as its sources include dairy products and meat.

Lactic acid occurs naturally in some foods, but manufacturers may add it to certain foods to extend their shelf life.

This article discusses what lactic acid is, vegan and nonvegan sources, and how a person can find out whether the source of the lactic acid in their food is vegan.

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Lactic acid is a naturally occurring substance that bacteria produce during fermentation.

Lactobacillus and Streptococcus cultures produce lactic acid. Foods such as pickled vegetables, jams, frozen desserts, baked goods, and dairy products all contain lactic acid.

When manufacturers add lactic acid to foods, it acts as a pH regulator and preservative.

The lactic acid that comes directly from fermented dairy products or meat is not vegan, but people following a plant-based diet will not be eating these foods anyway.

Most added lactic acid is a product of beet sugar or corn starch fermentation. Therefore, the majority of products containing lactic acid are vegan.

A person should be aware that the source of certain types of added lactic acid may originate from the byproducts of animals. For example, some lactic acid may come from bacteria feeding on lactose — a sugar found in dairy products.

However, once the lactic acid is in its final form and ready to add to food, its chemical structure is identical regardless of the original source of the carbohydrate. There will be no remnants of the animal product in it.

Some people may still wish to avoid lactic acid that has nonvegan origins, even though it itself contains no animal products. Manufacturers do not need to disclose the lactic acid source for their products, so a person may need to contact a company directly to find out whether it is vegan.

Many manufacturers use corn starch or beet sugar to produce lactic acid.

The process of creating lactic acid involves bacteria breaking down carbohydrates for energy, which is known as fermentation. During fermentation, the bacteria feed on glucose (sugar) for energy and produce lactic acid as a byproduct.

The bacteria that manufacturers may use to create lactic acid include:

  • Lactobacillus
  • Streptococcus
  • Enterococcus
  • Lactococcus
  • Bifidobacterium

Many plant-based foods in grocery stores contain lactic acid.

Some of these include:

  • sourdough bread
  • jars of pickled vegetables
  • sauerkraut
  • kimchi

People can also ferment their own foods at home if they want to consume lactic acid bacteria.

Some suitable vegetables include:

  • broccoli
  • beets
  • eggplant
  • turnips

Learn more about fermented foods here.

The Vegetarian Resource Group state that most lactic acid is from plant-based sources.

Although the Food and Drug Administration (FDA) approve the use of lactic acid in foods, they do not require companies to list the source of the lactic acid.

As a result, some products could contain lactic acid that originates from nonvegan sources. In these cases, the only way for a person to find out whether the source of the lactic acid is vegan is to contact the company directly.

Food manufacturers may add lactic acid to foods to prevent the growth of bacteria and extend shelf life. Many vegan foods, such as pickled vegetables and sauerkraut, include lactic acid.

Bacteria produce lactic acid as part of the fermentation process to extract energy from carbohydrates. In vegan lactic acid sources, the bacteria use either glucose or sucrose as a carbohydrate for fermentation.

Although most food manufacturers use lactic acid from vegan sources, the only way a person can know for sure is to contact the company directly.