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Evaluation of Microbial Safety of Dairies using Bacterial Proteomic Profiling via MALDI Approach
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Surface microflora of four smear-ripened cheeses
Jérôme Mounier1, Roberto Gelsomino, Stefanie Goerges
1Dairy Products Research Centre, Teagasc, Moorepark, Fermoy, Ireland.
Applied and Environmental Microbiology
|November 5, 2005
Summary
The microbial communities on Irish farmhouse smear-ripened cheeses are diverse, with yeast dominated by Debaryomyces hansenii and bacteria showing high species and strain-level variation. This highlights the crucial role of the natural microflora in cheese ripening.
Area of Science:
- Food Microbiology
- Dairy Science
- Cheese Technology
Background:
- The microbial ecology of smear-ripened cheeses is not well understood.
- Understanding the microflora is key to controlling cheese characteristics and ripening.
Purpose of the Study:
- To identify and characterize the bacterial and yeast populations on Irish farmhouse smear-ripened cheeses.
- To investigate the diversity of microbial species and strains present during ripening.
Main Methods:
- Bacterial and yeast isolates were identified using pulsed-field gel electrophoresis (PFGE), repetitive sequence-based PCR, 16S rRNA gene sequencing, Fourier transform infrared spectroscopy, and mitochondrial DNA restriction fragment length polymorphism (mtDNA RFLP).
- Microbial analysis was performed at the midpoint of the ripening process.
Main Results:
- The yeast microflora was uniform, dominated by Debaryomyces hansenii, with Yarrowia lipolytica found in low numbers.
- A high diversity of 14 bacterial species was identified, with each cheese exhibiting a unique microflora, though Corynebacterium casei and Arthrobacter arilaitensis were common.
- Significant strain-level diversity was observed in both bacterial and yeast populations.
Conclusions:
- The adventitious, resident microflora plays a significant role in the ripening of smear-ripened cheeses.
- Deliberately inoculated ripening cultures were not re-isolated, emphasizing the dominance of naturally occurring microbes.
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