Metabolic footprinting of Lactobacillus buchneri strain LA1147 during anaerobic spoilage of fermented cucumbers

Lactobacillus buchneri has recently been associated with anaerobic spoilage of fermented cucumbers due to its ability to metabolize lactic acid into acetic acid and 1,2-propanediol. However, we have limited knowledge of other chemical components in fermented cucumber that may be related to spoilage and the unique metabolic capabilities of L. buchneri. Comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry metabolite profiling methods were applied for nontargeted detection of volatile and nonvolatile compounds to determine changes that occurred during anaerobic fermented cucumber spoilage by L. buchneri LA1147 and during reproduction of spoilage with natural microbiota. Univariate analysis of variance combined with hierarchial clustering analysis revealed 92 metabolites that changed during spoilage (P < 0.01). Decreases were observed in mono and disaccharides, amino acids, nucleosides, long chain fatty acids, aldehydes, and ketones, and increases were observed in several alcohols and butanoic and pentanoic acids. Most of the metabolite changes preceded lactic acid utilization, indicating that lactic acid is not a preferred substrate for anaerobic spoilage organisms in fermented cucumbers. The ability to detect biochemical changes that preceded lactate utilization revealed citrulline, trehalose, and cellobiose as compounds that may signify metabolic activity of L. buchneri spoilage strains prior to any significant product degradation.