Submitted to: Applied and Environmental Microbiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/18/2001
Publication Date: 2/1/2002
Citation: Yoon, S.S., Barrangou-Poueys, R., Breidt, F., Klaenhammer, T.R., Fleming, H.P. 2002. Isolation and characterization of bacteriophages from fermenting sauerkraut. Applied and Environmental Microbiology. 68:973-976. Interpretive Summary: Bacterial viruses (called bacteriophage) that only attack bacterial cells and do not infect humans or animals have been found to attack and kill dairy fermentation starter cultures, but they have not previously been investigated in vegetable fermentations. Although starter cultures are not typically used in vegetable fermentations, current research on reducing salt waste and improving productivity and vegetable fermentation technology may result in processes requiring their use. This report has indicated there are a wide variety of viruses in both inoculated and uninoculated commercial cabbage fermentations, and viruses active against a starter culture were found. The bacterial viruses were isolated and characterized by electron microscopy, tested to determine growth rates in the infected bacteria, and studied to determine the number and types of bacteria they will infect. The viruses were found to be similar to the those common in dairy fermentations. To our knowledge, this is the first report in the scientific literature of bacterial viruses active in vegetable fermentations. This research on bacterial viruses and the effects they have on starter cultures may be important to the successful implementation of starter cultures in these fermentations. Research on these bacterial viruses may be important to maintain the competitiveness of the U.S. vegetable fermentation industry.
Technical Abstract: Brine samples from commercial (90-ton) sauerkraut fermentations were screened for the presence of bacteriophage. Host bacterial strains for these studies included isolates from the brine samples, as well selected lactic acid bacteria (LAB), including Leuconostoc mesenteroides C-33, which was used as a starter culture. Lytic phage active against the L. mesenteroides C-33 starter culture were recovered at a high frequency from an inoculated fermentation tank. Phage active against this culture were also recovered from an uninoculated tank, but at a lower frequency. Bacteriophage active against Lactobacillus plantarum and the LAB fermentation isolates were found in both the inoculated and control tanks. No bacteriophage were isolated from fermentation brine samples with a pH below 3.5. Bacteriophage were identified by morphology; isolates included seven Myoviridae, two Siphoviridae, and one Podoviridae phage. Growth kinetics were determined for all phage isolates. The largest burst size obtained was 250 particles per infective center for phage Y4, which was active against the L. mesenteroides C33 starter culture. These studies indicated that a variety of bacteriophage may be active in sauerkraut fermentations, and phage may influence the growth of Leuconostoc starter cultures in proposed commercial applications.