Zap, Mist, Gas: Non-Thermal Disinfection Battles Kimchi Cabbage Rot in Long-Term Storage

Napa cabbage is not just a vegetable in South Korea; it is the backbone of kimchi, a national staple whose annual supply has long depended on highland fields that grow cool enough in summer to yield dense, crisp heads. Climate change is quietly dismantling that system. Rising temperatures have reduced highland cabbage production, pushing growers toward spring-harvested cabbage that must survive months of cold storage before it reaches fermentation vats. The problem is that long-term storage of fresh cabbage is a biological minefield, dominated by fungal decay that can wipe out entire pallets. A new study from Korean food scientists now offers one of the most detailed commercial-scale assessments to date of how three non-thermal disinfection technologies perform against the chief culprit, the notorious fungal pathogen Sclerotinia sclerotiorum, over a 93-day refrigerated storage period.

The research, published in Food Science and Biotechnology, was conducted by Ji-Yeon Lee, Ju-Hui Lee, Eun-Young Chung, and Sang-Soon Kim across Konkuk University, Dankook University, and the Korea Agro-Fisheries and Food Trade Corporation. Rather than testing disinfection in laboratory beakers, the team evaluated three systems in commercial-scale cold rooms held at 1 plus or minus 0.5 degrees Celsius: hypochlorous acid water applied at concentrations of 50 to 80 parts per million, a dielectric barrier discharge cold plasma system generating roughly 30 parts per billion of ozone, and gaseous chlorine dioxide released in total amounts ranging from 12.96 to 22.68 grams. The choice of technologies is significant because all three are non-thermal, meaning they kill or suppress microorganisms without heat, avoiding the tissue damage that thermal treatments would inflict on delicate leafy vegetables.

Sclerotinia sclerotiorum is a formidable adversary in postharvest systems. The fungus causes Sclerotinia rot, a destructive disease of solanaceous and brassicaceous crops worldwide, and it survives in soil as hardened sclerotia that can germinate and infect stored produce when conditions turn humid and cool. In stored cabbage, infection spreads head to head, and a single decayed leaf can contaminate an entire pallet unit. Traditional control relies heavily on synthetic fungicides or chlorine washes, both of which face increasing regulatory and consumer resistance. This is precisely the gap the Korean team set out to fill, testing whether non-thermal disinfection could suppress the pathogen while preserving the quality attributes that make cabbage suitable for kimchi production.

The first headline finding is encouraging: all three systems suppressed mold growth during the storage trial. To confirm the identity of the spoilage organism, the researchers turned to molecular diagnostics rather than relying solely on visual symptoms. Using real-time polymerase chain reaction, they verified that the mold colonizing the stored cabbage was indeed Sclerotinia sclerotiorum. This matters because accurate pathogen identification underpins every subsequent decision about treatment efficacy. Visual decay can be caused by multiple fungi and bacteria, and misidentification could lead growers and storage operators to deploy the wrong intervention. The molecular confirmation anchors the study’s conclusions in a verifiable biological target.

Among the three technologies, chlorine dioxide emerged as the strongest antifungal agent. This gaseous oxidant has a growing track record in postharvest science; previous studies have shown it controlling green mold in citrus, suppressing postharvest fungi in longan fruit, and extending the freshness of strawberries during export. Its advantage lies in its ability to penetrate air spaces within palletized produce and reach surfaces that liquid sanitizers cannot easily contact. For a leafy, layered vegetable like Napa cabbage, where outer leaves shield inner ones, that gaseous reach is a genuine technical asset. The study’s results add Sclerotinia rot of cabbage to the list of postharvest diseases that chlorine dioxide can meaningfully suppress under realistic storage conditions.

But the story is not one of unqualified triumph, and this is where the research becomes genuinely instructive. Chlorine dioxide treatment came with a measurable cost: heads treated with the gas showed a significantly higher mean weight loss of 9.48 percent during days 79 to 93 of storage, a statistically significant difference at the p less than 0.05 level. The authors attribute this late-storage weight penalty to oxidative degradation of the epicuticular wax, the thin, waxy cuticular layer that coats cabbage leaves and acts as the plant’s primary barrier against water loss. In effect, the same oxidative chemistry that destroys fungal cells also erodes the vegetable’s own waterproofing. Once the wax layer is compromised, water vapor escapes faster, heads lose turgor, and marketable weight drains away. It is a textbook example of a postharvest trade-off between microbial control and physiological preservation.

The cold plasma system revealed a subtler complication. Dielectric barrier discharge plasma generates a cocktail of reactive oxygen and nitrogen species, including ozone at the roughly 30 parts per billion levels measured in this trial. While the plasma suppressed mold, the researchers observed localized reductions in soluble solids, the sugars and dissolved compounds that contribute to flavor and fermentation quality, in cabbage positioned near the device. The team interprets this as a dose-dependent physiological stress response: produce closest to the plasma source experiences the highest reactive species flux, and that oxidative stress appears to draw down the vegetable’s soluble carbohydrate reserves. For kimchi production, soluble solids are not a trivial metric, because the sugars available at fermentation time influence lactic acid bacterial activity and final product character. The finding suggests that plasma systems for whole-pallet cabbage will need careful engineering of dose uniformity, not just raw antimicrobial power.

Hypochlorous acid, the third technology, occupies a middle ground. Electrolyzed water and HOCl treatments have gained popularity as chlorine alternatives because the agent is effective at low concentrations and degrades into benign residues. Applied at 50 to 80 parts per million, it contributed to mold suppression without the dramatic weight loss penalty seen with chlorine dioxide. However, as a liquid or aerosol contact sanitizer, it faces the inherent limitation of any surface-applied treatment on a multilayered head of cabbage: penetration is imperfect, and protected microsites between leaves can harbor surviving inoculum that resurfaces later in storage.

Perhaps the most consequential finding for storage operators is temporal: the efficacy of all three systems declined after day 51 of the 93-day trial. Non-thermal disinfection, in other words, is not a set-and-forget solution for multi-month storage. Residual antimicrobial activity fades, whether because the oxidants dissipate, the released gas is exhausted, or surviving microbes adapt to the residual stress environment, a phenomenon consistent with broader research on microbial adaptations to bactericidal stresses. The authors conclude that integration with controlled atmosphere or modified atmosphere packaging is necessary for extended storage stability. This positions non-thermal disinfection not as a standalone fix but as the first line of a layered defense: an initial microbial knockdown followed by atmospheric modification that slows respiration and suppresses pathogen regrowth for the remainder of the storage period.

The broader context gives this work urgency. South Korea’s government purchases Napa cabbage for market stabilization, and the study was supported by the Korea Agro-Fisheries and Food Trade Corporation as part of a long-term storage demonstration project for government-purchased cabbage, with additional funding from the Korea AeroSpace Administration. As climate assessments continue to document shrinking highland growing capacity, the ability to store spring-harvested cabbage for three months or more becomes a matter of national food security, not merely agricultural convenience. What this study delivers is a realistic, commercial-scale evidence base: chlorine dioxide offers the strongest antifungal punch but demands wax-preserving dose optimization; cold plasma requires spatially uniform dosing to protect soluble solids; hypochlorous acid is a gentler but less penetrating option; and none of them alone can carry cabbage through a full storage season. The future of kimchi’s core ingredient, it turns out, will be engineered through combinations of technologies, calibrated leaf by leaf and day by day.

Subject of Research: Non-thermal disinfection of Sclerotinia sclerotiorum decay in stored Napa cabbage

Article Title: Effects of non-thermal disinfection systems on Sclerotinia sclerotiorum decay and quality attributes of spring-harvested Napa cabbage during long-term storage in South Korea

Article References: Lee, J.-Y., Lee, J.-H., Chung, E.-Y., & Kim, S.-S. (2026). Effects of non-thermal disinfection systems on Sclerotinia sclerotiorum decay and quality attributes of spring-harvested Napa cabbage during long-term storage in South Korea. Food Science and Biotechnology. https://doi.org/10.1007/s10068-026-02288-5

Image Credits: AI Generated

DOI: 10.1007/s10068-026-02288-5

Keywords: Napa cabbage, Sclerotinia sclerotiorum, chlorine dioxide, cold plasma, hypochlorous acid, postharvest quality, non-thermal disinfection, kimchi, food storage, climate change, real-time PCR, South Korea