Fermented Vegetables

The wide variety of fermented foods can be classified by the products of the fermentation, such as alcohol (beer, wine); organic acids, including lactic acid and acetic acid (vegetables, dairy); carbon dioxide (bread); and amino acids or peptides from protein (fish fermentations and others). Food fermentation is one of the earliest technologies developed by humans. The primary retail fermented vegetable products produced in the United States and Europe are cucumber pickles, olives, and sauerkraut. In Asia, a variety of fermented vegetable products are available, including pickles and fermented cabbage, notably kimchi in South Korea. The fermentation process for vegetables can result in nutritious foods that may be stored for extended periods, one year or more, without refrigeration. Prior to fermentation, fresh fruits and vegetables harbor a variety of microorganisms, including aerobic spoilage microflora such as Pseudomonas, Erwinia, and Enterobacter species, as well as yeasts and molds. Brining vegetables for fermentation results in the production by lactic acid bacteria (LAB) of organic acids and a variety of antimicrobial compounds. With the advent of whole-genome sequencing, it has become apparent that the LAB present in vegetable fermentations have relatively small genomes compared with many other mesophilic organisms. LAB isolated from vegetable fermentations frequently contain plasmids. Plasmid-borne genes encoding proteins involved in bacteriocin production, lactose utilization, and citric acid utilization have been isolated from several Leuconostoc species; however, none of these functions appears to be present in the ATCC 8293 plasmid.