Chromatography-Based Metabolomic Insights for Safer Kimchi Fermentation

Kimchi, despite its acidic environment, has sometimes been linked with foodborne pathogen contamination, a fact which stresses the necessity for the escalation of its microbial safety. While the fermentation of kimchi usually occurs at low temperatures, most of the previous studies on starter cultures have concentrated on mesophilic lactic acid bacteria (LAB). A joint study conducted by Chosun University and the World Institute of Kimchi (both in Gwangju, Republic of Korea) investigated the potential of psychrotrophic LAB as starter cultures for kimchi fermentation, with a special focus on their antimicrobial activity and metabolic characteristics. Untargeted metabolomics using ultrahigh-pressure liquid chromatography (UHPLC)-quadrupole-orbital trap mass spectrometry (MS) revealed strain-specific inhibition of metabolic pathways in foodborne pathogens. A paper based on this research was published in the International Journal of Food Microbiology. ⁽¹⁾

A traditional Korean fermented vegetable food, kimchi has attracted a great deal of attention due to its nutritional and functional properties, and especially in its potential for reducing obesity, lowering cholesterol, and stimulating the immune system. ^(2,3) Microbial contamination, especially due to acid-tolerant pathogens such as Escherichia coli, may occur in kimchi due to the food’s prolonged fermentation process, presence of diverse microbial communities, and its overall nutritional richness. ⁽⁴⁾ Starter cultures have gained attention as a promising strategy for erasing contamination, given their abilities to quicken the reduction of pH, stabilize the microbial community, and boost product safety, consistency, and sensory quality. ⁽⁵⁾

The research revealed that two psychrotrophic strains, Dellaglioa algida and Leuconostoc gelidum subsp. aenigmaticum, were individually co-inoculated with pathogens including Escherichia coli O157:H7, Staphylococcus aureus, and Listeria monocytogenes in kimchi and fermented at 4 °C for 42 days. Their performance was compared by the research team with that of a mesophilic LAB strain, Leu. mesenteroides, through microbial, physicochemical, and metabolomics analyses. The psychrotrophic starters accelerated acidification, maintained high dominance, and effectively suppressed pathogens. Moreover, E. coli O157:H7 counts were 1.8-2.4 log CFU/mL lower, and S. aureus reached the limit of detection (1.0 log CFU/mL) 7 days earlier than the mesophilic starter. It was discovered that D. algida primarily suppressed nucleotide metabolism, whereas Leu. gelidum subsp. aenigmaticum strongly inhibited energy-related and stress defense pathways, which ultimately affected pathogen growth negatively. Conversely, Leu. mesenteroides exhibited limited metabolic inhibition in comparison. Finally, psychrotrophic LAB displayed broad-spectrum antimicrobial activity and strain-specific inhibition mechanisms, which, in the opinion of the research team, emphasize their ability to play the role of functional starters for heightening microbial safety and reliability in low-temperature fermented foods. (1)

“These findings,” write the authors of the study,⁽¹⁾“highlight the potential of psychrotrophic LAB starters to enhance the microbial safety and stability in kimchi fermentation. Their stable performance at low temperatures supports their potential applicability in industrial-scale kimchi production and other cold-fermented foods.” The authors believe that “future studies exploring sensory attributes, safety aspects, and mixed-starter culture applications may further facilitate translation into practical and commercial use.” ⁽¹⁾

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References

1. Kim, D.; Hwang, I. M.; Kim, H. M. et al. Psychrotrophic Lactic Acid Bacteria Enhance Microbial Safety in Kimchi: Evidence from Untargeted Metabolomics. Int J Food Microbiol. 2026, 451, 111666. DOI: 10.1016/j.ijfoodmicro.2026.111666
2. Park, K. Y.; Hong, G. H.; Lee, S. Y. et al. Kimchi and its Antiobesity and Anticancer Functions. J. Ethn. Foods2024, 11, 37. DOI: 10.1186/s42779-024-00250-6
3. Şanlier, N.; Gökcen, B. B.; Sezgin, A. C. Health Benefits of Fermented Foods. Crit. Rev. Food Sci. Nutr.2019, 59 (3), 506-527. DOI: 10.1080/10408398.2017.1383355
4. Fidan, H.; Esatbeyoglu, T.; Simat, V. et al. Recent Developments of Lactic Acid Bacteria and their Metabolites on Foodborne Pathogens and Spoilage Bacteria: Facts and Gaps. Food Biosci. 2022, 47, 101741. DOI: 10.1016/j.fbio.2022.101741
5. Xu, J.; Peng, S.; Xiong, Y. et al. A Review on Fermented Vegetables: Microbial Community and Potential Upgrading Strategy via Inoculated Fermentation. Compr. Rev. Food Sci. Food Saf.2024, 23 (3), e13362. DOI: 10.1111/1541-4337.13362