Lactic acid bacteria directly degrade N-nitrosodimethylamine and increase the nitrite-scavenging ability in kimchi

- The effects of lactic acid bacteria on NDMA were investigated.
- Lactic acid bacteria can directly degrade NDMA.
- Lactic acid bacteria can indirectly reduce NDMA due to inhibition of precursors.
- Lactic acid bacteria can reduce NDMA levels in kimchi.

To investigate whether lactic acid bacteria (LAB) play a role in reducing the concentrations of N-nitrosodimethylamine (NDMA) and its precursors during kimchi production, experimental kimchi prepared with added Lactobacillus sakei, Lactobacillus curvatus, and Lactobacillus brevis was periodically monitored for 20 days to analyze the concentrations of NDMA, nitrite, dimethylamine (DMA), nitrate, and biogenic amines. LAB species in MRS broth with and without NDMA or NaNO2 were grown and NDMA and nitrite concentrations studied. The amounts of NDMA, nitrite, DMA, nitrate, and biogenic amines remaining in the LAB-fortified kimchi decreased significantly relative to that of the control kimchi. The effects of L. sakei and L. curvatus on the reduction of NDMA concentration in kimchi were higher than that of L. brevis. These LAB species might be indirectly reducing the amounts of NDMA in LAB-fortified kimchi by inhibiting the formation of NDMA precursors originating from kimchi. Interestingly, LAB were found to directly degrade NDMA during culture in MRS broth containing NDMA.