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

Foods. 2022 Jul 1;11(13):1960. doi: 10.3390/foods11131960.

Abstract

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 (102 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.

Keywords: Staphylococcus aureus; metabolites; sourdough; γ-aminobutyric acid.

Grants and funding

The research was funded by Changsha key S&T Special Projects (grant number: kh2003013), Key Projects of Hunan Education Department (grant number: 18A155) And The APC was funded by Changsha key S&T Special Projects.