Recovery of intact human norovirus from cabbage Kimchi stored at 4 °C and 10 °C during fermentation

- Norovirus (NoV) contamination in Kimchi can lead to outbreaks of foodborne disease.
- Lactic acid bacteria, pH, and acidity of Kimchi at 4 and 10 °C were measured over 28 day fermentation.
- Intact NoV titer was determined using magnetic bead isolation and quantitative PCR.
- Kimchi lactic acid fermentation conditions reduced but did not eliminate NoV load.
- Preventing transmission before fermentation might limit Kimchi NoV contamination.

This study aimed to evaluate the recovery of structurally intact human norovirus (NoV) during Kimchi fermentation at varying temperatures. Lactic acid bacteria (LAB), pH, and acidity during storage and fermentation were also measured to assess the correlation between NoV reduction and microbial or physicochemical property alterations. LAB number, NoV G titer, pH, acidity, and the ability of NoV GII.4 to persist in Kimchi stored at 4 °C and 10 °C (survivability) as determined using nano magnetic beads conjugated with poly(methyl vinyl ether-maleic anhydride) combined with quantitative real-time reverse transcription-polymerase chain reaction amplification were investigated up to 28 days post-inoculation. NoV was detected in all test samples after 28 days although the NoV recovery quantity was reduced to 1.31 (4 °C) and 1.66 (10 °C) log10 genomic copies/reaction. The time required to reduce the amount of virus by 2.57 log10 (td) on survival plots of NoV determined using a modified Weibull model was 2445 days at 4 °C and 138 days at 10 °C. These results indicate that NoV from food preparation or processing is able to persistently survive in Kimchi. Therefore, preventing NoV transmission is important for protecting Kimchi against NoV contamination.