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Previous studies using traditional biochemical identification methods to study the ecology of commercial sauerkraut fermentations revealed that four species of lactic acid bacteria, Leuconostoc mesenteroides, Lactobacillus plantarum, Pediococcus pentosaceus, and Lactobacillus brevis, were the primary microorganisms in these fermentations. In this study, 686 isolates were collected from four commercial fermentations and analyzed by DNA fingerprinting. The results indicate that the species of lactic acid bacteria present in sauerkraut fermentations are more diverse than previously reported and include Leuconostoc citreum, Leuconostoc argentinum, Lactobacillus paraplantarum, Lactobacillus coryniformis, and Weissella sp. The newly identified species Leuconostoc fallax was also found. Unexpectedly, only two isolates of P. pentosaceus and 15 isolates of L. brevis were recovered during this study. A better understanding of the microbiota may aid in the development of low-salt fermentations, which may have altered microflora and altered sensory characteristics.Sauerkraut fermentation involves many physical, chemical, and microbiological changes that influence the quality and safety of the product. This fermentation can be broadly categorized as having successive stages, including an initial heterofermentative stage followed by a homofermentative stage (11,22). Historically, four species of lactic acid bacteria (LAB) have been identified as organisms that are present in sauerkraut fermentations: Leuconostoc mesenteroides, Lactobacillus brevis, Pediococcus pentosaceus, and Lactobacillus plantarum. The identification of these microorganisms has been based on morphological and biochemical criteria (22). Several species of LAB other than the four species mentioned above have been found in cabbage fermentations, including Lactobacillus curvatus, Lactobacillus sakei, Lactococcus lactis subsp. lactis, and Leuconostoc fallax (3,19,25). Recently, six L. fallax strains were isolated from brine samples obtained from sauerkraut fermentations (2). The methods used for taxonomic characterization of LAB have been modified, and new species have been identified using molecular techniques (1,10,20,24). Improvements in molecular identification techniques for the study of microbial ecology have created new opportunities for the analysis of food fermentations.This study was carried out because of the need to reduce sodium chloride (salt) waste from commercial vegetable fermentations. It is well documented that the concentration of salt has a controlling influence on the microbial succession in a typical sauerkraut fermentation (11,12,22). It may be possible to reduce salt waste by fermenting cabbage with 1% salt instead of 2% salt, the concentration typically used. The introduction of an L. mesenteroides starter culture to the fermentation could help ensure that the initial stage of the fermentation produces the desirable flavor compounds (11). A method has been developed (23) to determine the ability of an unmarked starter culture to predom...

Knowledge of bacteriophage ecology in vegetable fermentations is essential for developing phage control strategies for consistent and high quality of fermented vegetable products. The ecology of phages infecting lactic acid bacteria (LAB) in commercial sauerkraut fermentations was investigated. Brine samples were taken from four commercial sauerkraut fermentation tanks over a 60-or 100-day period in 2000 and 2001. A total of 171 phage isolates, including at least 26 distinct phages, were obtained. In addition, 28 distinct host strains were isolated and identified as LAB by restriction analysis of the intergenic transcribed spacer region and 16S rRNA sequence analysis. These host strains included Leuconostoc, Weissella, and Lactobacillus species. It was found that there were two phage-host systems in the fermentations corresponding to the population shift from heterofermentative to homofermentative LAB between 3 and 7 days after the start of the fermentations. The data suggested that phages may play an important role in the microbial ecology and succession of LAB species in vegetable fermentations. Eight phage isolates, which were independently obtained two or more times, were further characterized. They belonged to the family Myoviridae or Siphoviridae and showed distinct host ranges and DNA fingerprints. Two of the phage isolates were found to be capable of infecting two Lactobacillus species. The results from this study demonstrated for the first time the complex phage ecology present in commercial sauerkraut fermentations, providing new insights into the bioprocess of vegetable fermentations.Like most vegetable fermentations, sauerkraut fermentation is spontaneous and relies on a very small population of lactic acid bacteria (LAB), which are naturally present on fresh vegetables, for preservation. It is known that a succession of various LAB species and their metabolic activities are responsible for the quality and safety of these products (25). The process is characterized by an initial heterofermentative stage, followed by a homofermentative stage. Heterofermentative Leuconostoc mesenteroides initiates the fermentation and quickly predominates the early stage of the fermentation because it is present at an initially higher number (approximately 10 3 CFU/ml) and has a shorter generation time at 18°C (the typical temperature of sauerkraut fermentation) than most other epiphytic LAB (22,23,24,25,27). The quality characteristics of sauerkraut are largely dependent upon the growth of this species (25). Between 3 and 7 days after the start of the fermentation, heterofermentative Leuconostoc species are usually succeeded by the more acid-tolerant homofermentative Lactobacillus species, due to the accumulation of lactic acid to 1% (wt/vol) or more and the decrease in pH below 4.5 (21, 25). Lactobacillus plantarum completes the fermentation, with a final pH of approximately 3.5 (25, 29).The correct sequence of LAB species is essential in achieving a stable product with the typical flavor and aroma of sauerkraut. It ...