2010 Annual Report
Brine samples were collected over a 90-day period and served as the source for the isolation of approximately 700 bacterial colonies belonging to the lactic acid bacteria (LAB) and enterobacteriacea groups. While isolates served as potential hosts, the filtered brine samples were used as phage sources. A total of 57 independent phage isolates against LAB were obtained, primarily from the seventh and fourteenth days of fermentation, in which the hosts reached maximum counts (109 CFU/ml). Representative LAB phages from each sampling day were characterized by electron micrographs. The majority of the phages were identified as members of the Myoviridae or Siphoviridae families, except for one phage belonging to the Podoviridae family. These phages showed distinct host ranges, protein profiles, and DNA fingerprints. Phage hosts were identified by 16S rDNA sequence analyses. LAB hosts include Weissella paramesenteroides, Weissella cibaria, Lactobacillus brevis, and Lactobacillus plantarum. Although, enteric phages and specific hosts have not been characterized, the LAB phages data suggest that a complex phage ecology with multiple isolates from a variety of families seems to be present in commercial cucumber fermentations, suggesting that phages may play an important role in the succession of LAB species in vegetable fermentations.
Progress on this project was made as a team effort, thus communication via e-mail and phone calls was frequent. Discussion meetings were scheduled as necessary.