Yeast community in traditional Portuguese Serpa cheese by culture-dependent and -independent DNA approaches

Abstract

This study investigated the yeast community present in the traditional Portuguese cheese, Serpa, by culture-dependent and -independent methods. Sixteen batches of Serpa cheeses from various regional industries registered with the Protected Designation of Origin (PDO) versus non-PDO registered, during spring and winter, were used. Irrespective of the producer, the yeast counts were around 5log CFU/g in winter and, overall, were lower in spring. The yeast species identified at the end of ripening (30days), using PCR-RFLP analysis and sequencing of the 26S rRNA, mainly corresponded to Debaryomyces hansenii and Kluyveromyces marxianus, with Candida spp. and Pichia spp. present to a lesser extent. The culture-independent results, obtained using high-throughput sequencing analysis, confirmed the prevalence of Debaryomyces spp. and Kluyveromyces spp. but, also, that Galactomyces spp. was relevant for three of the five producers, which indicates its importance during the early stages of the cheese ripening process, considering it was not found among the dominant viable yeast species. In addition, differences between the identified yeast isolated from cheeses obtained from PDO and non-PDO registered industries, showed that the lack of regulation of the cheese-making practice, may unfavourably influence the final yeast microbiota. The new knowledge provided by this study of the yeast diversity in Serpa cheese, could be used to modify the cheese ripening conditions, to favour desirable yeast species. Additionally, the prevalent yeast isolates identified, Debaryomyces hansenii and Kluyveromyces spp., may have an important role during cheese ripening and in the final sensorial characteristics. Thus, the study of their technological and functional properties could be relevant, in the development of an autochthonous starter culture, to ensure final quality and safety of the cheese.

Yeasts and bacteria associated with kocho, an Ethiopian fermented food produced from enset (Ensete ventricosum)

“…Apart from assimilating sugars and lactic acid, the yeast is supposed to hydrolyse lipids and proteins and to inhibit the formation of biogenic amines, which has a positive influence on the taste of the final product (Grygier et al 2017). C. cabralensis has been isolated from Spanish blue-veined Cabrales cheese and from Portugese Serpa cheese (Flórez et al 2010; Gonçalves Dos Santos et al 2017). In fact, our study is the first documented isolation of this yeast from another source than cheese.…”

Cheese yeasts

“…K . marxianus is also found frequently in young or short‐ripened cheeses (Cardoso et al, ; Ceugniez, Drider, Jacques, & Coucheney, ; Goncalves Dos Santos, Benito, de Guia Cordoba, Alvarenga, & Ruiz‐Moyano Seco de Herrera, ) as well as in yellow‐type acid‐curd cheeses (Bockelmann, ).…”

Sequencing of the Cheese Microbiome and Its Relevance to Industry

“…HTS analysis of this fungal community of both PDO and non-PDO forms of Serpa cheeses, highlighted diversity among the yeasts present in a manner suggested that production practices and the associated environment have a considerable influence on the final yeast population. Through these investigations it was possible to alter ripening conditions to favor the dominance of yeast species that are desirable for optimal Serpa production (Gonçalves Dos Santos et al, 2017 ). Another ewe's milk cheese produced by traditional techniques without starters, in this case from Croatia, has also been the subject of HTS-based analysis.…”

“…There have been a number of research and review papers dedicated to describing methodologies used for sequencing (Di Bella et al, 2013 ) work flow, limitations, applications to dairy foods (Ercolini, 2013 ; Walsh et al, 2017 ), comparing sequencing platforms, and bioinformatics pipelines as well as highlighting pros and cons associated with all of the above (Kelleher et al, 2015 ; Clooney et al, 2016 ; Walsh et al, 2018 ) Depending on sequencing depth, HTS can facilitate the detection of taxa present at low levels, a feature of great value in the context of testing for spoilage or pathogenic microbes. HTS technology can also be employed to study the microbial diversity of protected designation of origin (PDO) cheeses to establish which components are responsible for the authentic taste, flavors, and textures of these products (Alegría et al, 2012 ; Fuka et al, 2013 ; De Filippis et al, 2014 ; Delcenserie et al, 2014 ; De Pasquale et al, 2014 , 2016 ; Riquelme et al, 2015 ; Dalmasso et al, 2016 ; Parente et al, 2016 ; Giello et al, 2017 ; Gonçalves Dos Santos et al, 2017 ; Li et al, 2017 ). The same technology could, in the future, be employed to establish authenticity.…”