Kimchi bacteriophages of lactic acid bacteria: population, characteristics, and their role in watery kimchi.

The bacteriophages (phages) in the watery kimchis (Baek-kimchi and Dongchimi) were characterized to determine the phage ecology of lactic acid bacteria (LAB). Kimchi obtained from the Seoul markets had an average of 2.1 log phage particles/mL, corresponding to 28% of the bacterial counts on a log scale. High counts of 5.5-6.5 log particles/mL of phages were noted in the early phase of fermentation (reaching pH 4), and 2.1-3.0 log phage particles/mL were found in the later phase, with some fluctuation in numbers. The LAB hosts changed from Weissella and Leuconostoc to Lactobacillus during Dongchimi fermentation. Fifteen phages, except for those of Lactobacillus, were isolated from diverse strains in the early phase. Five Weissella phages were Podoviridae, and all 10 Leuconostoc phages were Myoviridae. Phages had narrow and different host infection spectra to strains of the same species and high acidic stability. Therefore, the mortality and diversity of LAB during natural kimchi fermentation may be related to the specific phages of the hosts. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10068-021-00930-y. © The Korean Society of Food Science and Technology 2021.