Dynamic Interplay between Microbiota Shifts and Differential Metabolites during Dairy Processing and Storage.

Area of Science:

• Food Science and Technology
• Microbiology
• Metabolomics
• Metagenomics

Background:

• Traditional methods struggle to identify factors affecting dairy quality due to complex microbiota and residual components.
• Heat-resistant enzymes and microbial activity significantly influence milk's shelf-life and quality.
• Understanding microbial and metabolic changes is crucial for effective dairy processing and storage.

Purpose of the Study:

• To investigate the intricate factors affecting dairy quality using advanced multi-omics approaches.
• To identify specific microorganisms and metabolites influencing the quality evolution of raw, pasteurized, and ultra-heat-treated (UHT) milk during storage.
• To elucidate the roles of microbial growth and heat-resistant enzymes in dairy product spoilage.

Main Methods:

• Collective analysis of raw, pasteurized, and UHT milk samples using metagenomic next-generation sequencing (mNGS).
• High-throughput liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) for metabolite profiling.
• Correlation analysis between microbial abundance and metabolite changes to identify key players in dairy quality evolution.

Main Results:

• Distinct microbiota shifts and metabolite changes were observed between raw milk and its heated counterparts during storage.
• Microbacterium, unclassified Actinomycetia, and Micrococcus were identified as key proliferating microorganisms in pasteurized milk, highly correlated with specific metabolites.
• Pseudomonas and Acinetobacter were implicated in milk spoilage via heat-resistant enzymes, while other microbes showed lower impact.

Conclusions:

• The synergy of metagenomics and metabolomics provides a comprehensive understanding of dairy quality determinants.
• Protein degradation is linked to microbial growth, while lipid degradation is associated with raw milk's heat-resistant enzymes.
• This integrated approach offers novel insights for optimizing dairy processing and storage strategies.