Effect of Staphylococcus aureus Contamination on the Microbial Diversity and Metabolites in Wholewheat Sourdough.

Wholewheat sourdough products are becoming increasingly more popular, and Staphylococcus aureus is a common opportunistic pathogen in dough products. The effects of S. aureus contamination (10 2 cfu/g) on metabolites as well as titratable acidity (TTA), pH, and microbial diversity of sourdough were investigated. S. aureus contamination significantly decreased the content of mannose while increasing the sorbitol in sourdough ( p < 0.05). The S. aureus contamination significantly reduced the number of lactic acid bacteria (LAB), such as Lactobacillus curvatus , and the TTA values ( p < 0.05). Furthermore, S. aureus contamination significantly reduced the content of most esters and acid flavor compounds while significantly increasing the content of 2,4-decadienal ( p < 0.05), which is a compound that could have a negative impact on the flavor of sourdough. The PCA model developed based on volatile metabolites data could be used to distinguish contamination of S. aureus in sourdough cultured for 4 h. Sorbitol, 2,3-dimethylundecane, 1-pentanol, and 3-methylbutanoic acid were newly found to be the characteristic metabolites in S. aureus -contaminated sourdough.