Electrically Charged Disinfectant Containing Calcium Hydrogen Carbonate Mesoscopic Crystals as a Potential Measure to Control <i>Xanthomonas campestris</i> pv. <i>campestris</i> on Cabbage Seeds

• Main Authors: Akikazu Sakudo, Makoto Haritani, Koichi Furusaki, Rumiko Onishi, Takashi Onodera
• Format: Article
• Language: English
• Published: MDPI AG 2020-10-01
• Series: Microorganisms
• Subjects: bacterium; black rot; food safety; germination; plant stem growth; seeds
• Online Access: https://www.mdpi.com/2076-2607/8/10/1606

<i>Xanthomonas campestris</i> pv. <i>campestris</i> (<i>Xcc</i>) is an important seed-borne bacterial pathogen that causes black rot in brassica. Current seed disinfection methods for <i>Xcc </i>have disadvantages; chemical treatment has associated environmental risks, hot water immersion reduces germination, and dry heat treatment is protracted. Here, we treated <i>Xcc</i>-contaminated seeds with CAC-717, a recently developed disinfectant produced by applying an electric field and water flow to distilled water containing calcium hydrogen carbonate to produce mesoscopic crystals. The decimal reduction time (<i>D</i>-value) of <i>Xcc</i> suspension (8.22 log₁₀ colony forming units (CFU)/mL) by CAC-717 treatment was 0.319 min. Treatment of <i>Xcc</i>-contaminated cabbage seeds at 25 °C for 30 min with CAC-717 significantly reduced bacterial cell numbers recovered from the seeds (0.36 log₁₀ CFU/mL (SEM (standard error of the mean) = 0.23 log₁₀ CFU/mL)) compared with distilled water treatment (3.52 log₁₀ CFU/mL (SEM = 0.12 log₁₀ CFU/mL)). Moreover, there was a lower incidence of black rot after treatment with CAC-717 (26.67% ± 3.33%) versus distilled water (56.67% ± 8.82%). For non-contaminated seeds, there was no significant difference in germination rate and plant stem length between distilled water and CAC-717 treatment after 5 days of cultivation. In conclusion, CAC-717 is a promising seed disinfectant without deleterious effects on germination or plant growth.