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Updated: May 31, 2026
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Novel Production Protocol for Small-scale Manufacture of Probiotic Fermented Foods
Published on: September 10, 2016
Metabolic reprogramming for post-acidification control in fermented milk via post-sterilization treatment.
Han Lu1, Liru Cui2, Menglu Li2
1College of Food Science and Biology, Hebei University of Science and Technology, Shijiazhuang, Hebei, 050018, China; Junlebao Dairy Group Co., Ltd., Shijiazhuang, Hebei, 050221, China; Shanghai Jiao Tong University, Shanghai, 200240, China.
Food Microbiology
|May 29, 2026
Summary
Post-sterilization of fermented milk causes sublethal bacterial injury, not death. This state reduces metabolic activity, mitigating post-acidification and extending shelf life while maintaining high cell counts.
Area of Science:
- Food Microbiology
- Fermentation Science
- Dairy Technology
Background:
- Post-sterilization is a common method to extend the shelf life of fermented milk.
- The conventional understanding is that post-sterilization eliminates starter cultures, halting metabolic activity.
- This study investigates the actual impact of post-sterilization on microbial viability and metabolism.
Purpose of the Study:
- To elucidate the mechanistic framework behind post-sterilization's effect on fermented milk.
- To challenge the conventional view of microbial inactivation by post-sterilization.
- To understand how post-sterilization mitigates post-acidification and extends shelf life.
Main Methods:
- Integrated analysis of viable cell counts, pH, and titratable acidity.
- Enzyme activity assays (β-galactosidase, lactate dehydrogenase).
- Quantitative PCR (qPCR) for gene expression and untargeted metabolomics.
Main Results:
- Post-sterilization reduced viable counts by only one order of magnitude, inducing a sublethal injured state.
- Metabolic activity was significantly suppressed, evidenced by blocked lactose utilization and arrested metabolic pathways.
- Stringent response activation (ppGpp) redirected metabolism towards repair and survival, with upregulated F0F1-ATPase and DNA repair genes.
Conclusions:
- Post-sterilization alleviates post-acidification not by killing bacteria, but by inducing sublethal injury.
- This results in a state of high cell count but low metabolic activity, balancing shelf life and energy efficiency.
- Provides a theoretical basis for optimizing fermented dairy manufacturing processes.
Keywords:
Fermented milkMetabolic reprogrammingPost-acidificationPost-sterilizationlactate dehydrogenaseppGppβ-galactosidaseMore Related Videos
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