Influence of cabbage farming practice and potato peel addition on the endpoint microbial community in sauerkraut fermentation.

Abstract

The microbial dynamics and lactic acid bacteria (LAB) content of sauerkraut are influenced by various factors. Understanding microbial variations and pathogen-exclusion capacity in spontaneously fermented vegetables is essential for reducing risks in home-style fermentation systems. We investigated the effects of conventional versus organic farming practices and potato peel addition on LAB counts and microbial diversity at days 14 and 21 of fermentation. We tested the susceptibility of different fermentations to the proliferation of a human bacterial pathogen modelled by a surrogate challenge test with Listeria innocua. We monitored the presence of Leuconostoc mesenteroides and Lactiplantibacillus plantarum at different fermentation stages. LAB counts were slightly boosted by potato peel addition until day 14. Day 21 sauerkraut samples with added potato peel sourced from conventional farming practice resulted in significantly higher LAB counts than organic samples. PERMANOVA based on Bray-Curtis dissimilarity indicated dissimilar microbiota between organic and conventional sauerkraut, while potato peel addition showed no significant effect. The presence of distinct taxa in certain samples highlights the strong influence of raw material microbiota on the final fermented product. Cultivation-based analysis combined with qPCR assessment revealed a decline of L. mesenteroides and a progressive increase of L. plantarum during sauerkraut fermentation. The contrasting amplicon sequencing results showing the presence of L. mesenteroides at the later fermentation stage underscore the need to combine cultivation with sequencing to accurately track community succession. The surrogate pathogen challenge test showed no recovery of L. innocua.