With the growing global emphasis on health and wellness, fermented foods have garnered increasing attention (Diez-Ozaeta and Astiazaran, 2022). Kimchi, a traditional Korean fermented vegetable food, has attracted significant attention for its nutritional and functional properties, including its potential to reduce obesity, lower cholesterol, and stimulate the immune system (Park et al., 2024; Şanlier et al., 2019). Kimchi is prepared by mixing salted kimchi cabbage with seasonings such as red pepper powder, garlic, and green onion, followed by fermentation. Kimchi is generally considered safe due to the salting process and the acidic environment generated by lactic acid bacteria (LAB) during fermentation. Nevertheless, microbial contamination, particularly by acid-tolerant pathogens such as Escherichia coli, may occur because of the prolonged fermentation process, presence of diverse microbial communities, and nutritional richness of kimchi (Fidan et al., 2022). This vulnerability has been implicated in several foodborne illness outbreaks. For instance, a major outbreak of enterotoxigenic E. coli O169 linked to kimchi served in schools in the Republic of Korea resulted in more than 1600 cases in 2012 (Cho et al., 2014). Additional outbreaks involving Shiga toxin-producing E. coli O157:H7 have been reported in other countries, notably Japan and Canada (Ozeki et al., 2003; Smith et al., 2023). Prior studies have also confirmed that major foodborne pathogens, including E. coli O157:H7, Staphylococcus aureus, and Listeria monocytogenes, can survive during kimchi fermentation (Gill et al., 2024; Inatsu et al., 2004).

Various approaches, including high pressure, thermal processing, gamma irradiation, gas packaging, and natural or microbial additives, have been investigated to improve microbial safety (Choi et al., 2025b; Jang et al., 2015; Kim et al., 2008; Kim et al., 2021b). However, their application remains limited because of negative effects on flavor, texture, and appearance. Starter cultures have gained attention as a promising strategy owing to their abilities to accelerate pH reduction, stabilize the microbial community, and enhance product safety, consistency, and sensory quality (Xu et al., 2024). Jeong et al. (2024) reported that a nisin-producing Lactococcus lactis strain inhibited autochthonous LAB, contributing to microbial stabilization, and extended shelf life during kimchi fermentation. Lactobacillaceae starters also stabilized the microbial population and enhanced flavor by producing unique metabolites (Lee et al., 2025). These findings suggest that starter cultures can modulate indigenous LAB population, stabilize microbial community, and establish a more controlled fermentation ecosystem, which is essential for ensuring consistent product quality in industrial applications.

However, most studies on kimchi starters have focused on mesophilic strains. As kimchi is typically fermented at temperatures below 10 °C, it provides an optimal environment for psychrotrophic LAB that remain metabolically active at these low temperatures, whereas mesophilic strains are inherently limited in adapting to such conditions. Psychrotrophic LAB such as Dellaglioa algida and Leuconostoc gelidum are indigenous to kimchi and have since long been traditionally consumed, supporting their safety for human consumption (Jeong et al., 2013; Lee et al., 2018; Song et al., 2021). D. algida (formerly Lactobacillus algidus) and Leu. gelidum have been detected in various foods, including fish, dairy products, vegetables, and are particularly prevalent in chilled meat products, where they frequently occur as dominant psychrotrophic LAB (Johansson et al., 2022; Parente et al., 2023). These species were previously regarded as meat-spoilage organisms responsible for sensory deterioration; however, accumulating evidence indicates that their presence does not necessarily correlate with actual spoilage (Mansur et al., 2019). Recent genomic and physiological studies have begun to clarify their functional traits, including adaptation to low temperatures, production of exopolysaccharides with bioactive properties, and antimicrobial activities (Johansson et al., 2022; Sun et al., 2022; Sun et al., 2024; Werum and Ehrmann, 2024; Wong and Li, 2023). Research on kimchi-derived psychrotrophic LAB has also increased, particularly with respect to isolation and characterization (Ko et al., 2023, Ko et al., 2024a, Ko et al., 2024b; Mun et al., 2021), but their application as starter cultures remains limited. Considering their natural occurrence in kimchi, history of safe consumption, and metabolic activity at low temperatures, psychrotrophic LAB represent promising starter candidates for industrial cold-chain fermentation systems, where microbial safety and quality must be maintained under refrigerated conditions.

In this study, psychrotrophic LAB strains showing antimicrobial activity were employed as kimchi starters and evaluated for their ability to control foodborne pathogens during the fermentation process. Untargeted metabolomics was further conducted to elucidate the metabolic interactions between psychrotrophic LAB and pathogens, providing insights into their antimicrobial mechanisms.