# Microbiota \"Fingerprint\" of Greek Feta Cheese through Ripening
###### Abstract  
Feta is a Greek protected designation of origin (PDO) primed curd white cheese made from small ruminants' milk. In the present research, Greek Feta cheese bacterial diversity was evaluated via matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Analysis of 23 cheese samples, produced in different regions of the country, was performed in two ripening times (three or six months post-production). The identified microbiota were primarily constituted of lactic acid bacteria. A total of 13 different genera were obtained. The dominant species in both ripening times were _Lactobacillus plantarum_ (100.0% and 87.0%, at three or six months post-production, respectively), _Lactobacillus brevis_ (56.5% and 73.9%), _Lactobacillus paracasi_ (56.5% and 39.1%), _Lactobacillus thammosus_ (13.0% and 17.4%), _Lactobacillus marplantarum_ (4.3% and 26.1%), _Lactobacillus curvatus_ (8.7% and 8.7%). Other species included _Enterococcus faecalis_ (47.8% and 43.5%), _Enterococcus facetum_ (34.8% and 17.4%), _Enterococcus durations_ (13.0% and 17.4%), _Enterococcus malodoratus_ (4.3% and 4.3%), and _Streptococcus saliarius subsp. thermophilus_ (21.7% and 30.4%). The increased ripening time was found to be correlated to decreased total solids (r = 0.616; \(p\) = 0.002), protein (r = 0.683; \(p\) < 0.001), and PH (r = 0.780; \(p\) < 0.001). The results of this study contribute to a better understanding of the core microbiota of Feta cheese. Feta cheese; microbiota; safety; ripening; MALDI-TOF MS 2021 26 May 2021 26 May 2021 26 June 2021 26 May 2021 26 June 2021 2  
This has as a result to generate a characteristic mass and intensity distribution of the mainly ribosomal proteins, representing a \"molecular fingerprint\". Some advantages stemming from this technology include the increase in the reporting of some relatively rare species over traditional methods, the easy pretreatment of samples, the quick identification results, and the lower costs. At the moment, MALDI-TOF MS profiling is accepted as a universally valid identification method and is used in food microbial ecology studies, including those on dairy products [5]. A recent study used MALDI-TOF MS to identify non-starter lactic acid bacteria (NSLAB) isolates from four artisanal kinds of cheeses, namely Kefalotyi, Anthotyro, Xynotyri, and Touloumotyi, synthesized from raw goat and sheep milk. The identified lactic acid bacteria (LAB) species included _Lactobacillus brevis_, _Lactobacillus rhamnosus_, _Lactobacillus plantarum_, _Lactobacillus paracasei_, _Leuconstoc mesenteroides_, _Enterococcus ficeium_, _Lactococcus lactis_, and _Pediococcus pentosaceus_[6]. [PERSON] et al. assessed the LAB strains in breast milk, feces of mothers and babies, and local foods (fermented) using genotypic tools such as 16S RNA gene sequencing, random amplified polymorphic DNA (RAPD) and MALDI-TOF [7]. Feta PDO is defined by its distinctive organoleptic features. Various microbial populations coexist, operate, and interact, providing through their metabolism, the development of taste, texture, aroma, safety, and shelf-life of the cheese [8]. These microbiota dynamics and changes control both organoleptic and biosafety characteristics, thus defining the quality of the product [9]. The microflora of cheeses differ through time and are based on the cheese type, as well as the environmental, processing, and aging conditions. Feta cheese microbiota are originated from the milk microbiota of indigenous sheep and goat breeds, the starter lactic acid bacteria and the secondary microflora [6]. The starter lactic acid bacteria (SLAB), are inoculated starter cultures, involved in acid production during manufacture and contribute to the ripening process. Secondary microorganisms are not responsible for acid production during manufacture, but generally play an important role during ripening as these bacteria contribute to the lipolysis and proteolysis of cheese [10].