Characterization of Bacterial Microbiota of P.D.O. Feta Cheese by 16S Metagenomic Analysis.

Panagiotis Papadakis,Despina Vougiouklaki,Efstathia Tsakali,Anthimia Batrinou,Theofania Tsironi,Panagiotis Halvatsiotis,Jan F M Van Impe,Sotiris Ouzounis,Irini F Strati,Dimitra Houhoula,Spyros Konteles

doi:10.3390/microorganisms9112377

Abstract

Background: The identification of bacterial species in fermented PDO (protected designation of origin) cheese is important since they contribute significantly to the final organoleptic properties, the ripening process, the shelf life, the safety and the overall quality of cheese. Methods: Ten commercial PDO feta cheeses from two geographic regions of Greece, Epirus and Thessaly, were analyzed by 16S metagenomic analysis. Results: The biodiversity of all the tested feta cheese samples consisted of five phyla, 17 families, 38 genera and 59 bacterial species. The dominant phylum identified was Firmicutes (49% of the species), followed by Proteobacteria (39% of the species), Bacteroidetes (7% of the species), Actinobacteria (4% of the species) and Tenericutes (1% of the species). Streptococcaceae and Lactobacillaceae were the most abundant families, in which starter cultures of lactic acid bacteria (LAB) belonged, but also 21 nonstarter lactic acid bacteria (NSLAB) were identified. Both geographical areas showed a distinctive microbiota fingerprint, which was ultimately overlapped by the application of starter cultures. In the rare biosphere of the feta cheese, Zobellella taiwanensis and Vibrio diazotrophicus, two Gram-negative bacteria which were not previously reported in dairy samples, were identified. Conclusions: The application of high-throughput DNA sequencing may provide a detailed microbial profile of commercial feta cheese produced with pasteurized milk.

Highlights

Feta cheese is a salty and slightly acidic traditional white soft cheese of ancient Greek origin characterized as PDO by the European Community which accounts for approximately 10% of the Greek food exports due to its significant international reputation [1]
The biodiversity of all the feta cheese samples analyzed consisted of 59 bacterial
The dominant species corresponding genera, The biodiversity of all the feta cheese samples analyzed consisted of 59 bacterial phylum identified was Firmicutes (49% of the species), followed by Proteobacteria

Summary

Introduction

Feta cheese is a salty and slightly acidic traditional white soft cheese of ancient Greek origin characterized as PDO (protected designation of origin) by the European Community which accounts for approximately 10% of the Greek food exports due to its significant international reputation [1]. The application of high-throughput DNA sequencing, such as NGS, can facilitate the detection of all the microbial species that were present from farm to plant and up to the moment of the specific analysis, providing an extensive picture of the microbial “history” of the cheese by identifying various categories of microorganisms of the microbial community. This thorough analysis can reveal (a) active species found in abundant quantities, (b) inactive species that may be either dead or metabolically lethargic due to environmental stresses,. Conclusions: The application of high-throughput DNA sequencing may provide a detailed microbial profile of commercial feta cheese produced with pasteurized milk

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