Microbes in the Production of Fermented Foods

Lactic acid bacteria, a group of gram-positive bacteria, can ferment carbohydrate-based plant materials to preserve and improve their flavor.

For example, microbial fermentation of cabbage produces sauerkraut.

The process begins with lactic acid-producing cocci, such as Leuconostoc mesenteroides, which convert sugars from cabbage into lactic acid and other metabolites.

As acidity reaches about 1% of the mixture, acid-tolerant bacilli such as Levilactobacillus brevis and Lactiplantibacillus plantarum become dominant and continue fermentation.

Once the lactic acid levels reach about 1.3% of the mixture, the acidic environment prevents spoilage and preserves the flavor.

Similarly, cucumbers are fermented in a 5% brine. The high salt concentration draws water and sugar out of the cucumbers.

These sugars are then broken down by Leuconostoc mesenteroides, Pediococcus acidilactici, and Lactiplantibacillus plantarum to produce lactic acid.

As the environment becomes more acidic, L. plantarum dominates, inhibiting spoilage microbes and enhancing the pickle’s flavor.