Candida species covered from traditional cheeses: Characterization of C. albicans regarding virulence factors, biofilm formation, caseinase activity, antifungal resistance and phylogeny

This study has provided characterization data (carriage of virulence, antifungal resistance, caseinase activity, biofilm-forming ability and genotyping) of Candida albicans isolates and the occurrence of Candida species in traditional cheeses collected from Kayseri, Türkiye. Phenotypic (E-test, Congo red agar and microtiter plate tests) and molecular tests (identification, virulence factors, biofilm-formation, antifungal susceptibility) were carried out. The phylogenetic relatedness of C. albicans isolates was obtained by constructing the PCA dendrogram from the mass spectra data. Of 102 samples, 13 (12.7%) were found to be contaminated with C. albicans, 15 (14.7%), 10 (9.8%) and five (4.9%) were found to be contaminated with C. krusei, C. lusitane and C. paraplosis, respectively. While seven (16.2%) of 43 Candida spp. isolates were obtained from cheese collected from villages, 36 (83.7%) belonged to cheeses collected from traditional retail stores. The carriage rate of C. albicans isolates belonging to virulence factors HSP90 and PLB1 genes was 30.7%. ALST1, ALST3, BCR, ECE, andHWP (virulence and biofilm-associated) genes were harbored by 30.7%, 23%, 38.4%, 53.8%, and 38.4% of the 13 isolates. According to the microplate test, eight (61.5%) of 13 isolates had strong biofilm production. ERG11 and FKS1 (antifungal resistance genes) were found in 46.1% and 23% of 13 isolates, respectively. Due to missense mutations, K128T, E266D and V488I amino acid changes were detected for some isolates regarding azole resistance. As a result of the E-test, of the 13 isolates, one (7.6%) was resistant to flucytosine, four (30.7%) were resistant to caspofungin, and nine (69.2%) were resistant to fluconazole. The PCA analysis clustered the studied isolates into two major clades. C. albicans isolates of traditional cheese collected from villages were grouped in the same cluster. Among the C. albicans isolates from village cheese, there were those obtained from the same dairy milk at different times. Samples from the same sales points produced at different dairy farms were also contaminated with C. albicans. Concerning food safety standards applied from farm to fork, in order to prevent these pathogenic agents from contaminating cheeses, attention to the hygiene conditions of the sale points, conscious personnel, prevention of cross contamination will greatly reduce public health threats in addition to the application of animal health control, milking hygiene, pasteurization parameters in traditional cheese production.

Microbial screening of animal skin bags used in traditional cheesemaking

Bouhezza is a traditional Algerian cheese produced and ripened in goatskin bags called Djeld. The aim of this study was to characterize the microbial ecosystem from Djeld (fresh and dried Djeld for making Bouhezza cheese) and the changes introduced by Lben microflora during its preparation and to identify its role in cheesemaking and its safety. Two replicates of fresh and dried skin bags (FS and DS) were sampled and analyzed before and after contact with Lben. The microbiological results showed no pathogens. Skins observed before the addition of Lben were less populated 2.86 and 3.20 log CFU cm-2 than skins examined after the addition of Lben (approximately 6.0 log CFU cm-2), suggesting a potential role of Lben in releasing some microorganisms into the skin during its time in the Djeld. However, an increase in mesophilic lactic acid bacteria and yeasts was observed in Lben after different periods of interaction with the skin. PCR-TTGE revealed the predominance of lactic acid bacteria (Lactiplantibacillus plantarum, Limosilactobacillus fermentum, Staphylococcus equorum subsp. linens, Lactococcus cremoris, Streptococcus thermophilus) and a few high-GC-content bacteria (Lacticaseibacillus paracasei, Brevibacterium casei). Transfer of several microbial species was observed between the goatskin bag biofilm and Lben during the overnight interaction. Bands corresponding to Lacticaseibacillus paracasei, Brevibacterium casei, and Lactobacillus delbrueckii subsp. lactis were detected in the fresh skin profile and in Lben after contact with the fresh skin. Lacticaseibacillus paracasei was found in dried skin and Lben after contact with dry skin. Lactobacillus helveticus and Enterococcus faecalis appeared in the Lben profile and persisted in Lben and the biofilm-covered dry skin after interaction. These results demonstrate an exchange of specific microbial populations between goatskin bag biofilm and Lben during the traditional preparation method, suggesting that the diversity of goatskin biofilm contributes to the microbial diversity of Lben used in the production of Bouhezza cheese.

Compositional Differences of Greek Cheeses of Limited Production

Greece has a long tradition in cheesemaking, with 22 cheeses registered as protected designation of origin (PDO), 1 as protected geographical indication (PGI), and 1 applied for PGI. Several other cheeses are produced locally without any registration, which significantly contribute to the local economy. The present study investigated the composition (moisture, fat, salt, ash, and protein content), color parameters, and oxidative stability of cheeses that do not have a PDO/PGI certification, purchased from a Greek market. Milk and cheese types were correctly assigned for 62.8 and 82.1 % of samples, respectively, through discriminant analysis. The most important factors for milk type discrimination were L, a and b color attributes, salt, ash, fat-in-dry-matter, moisture-in-non-fat-substance, salt-in-moisture, and malondialdehyde contents, whereas a and b, and moisture, ash, fat, moisture-in-non-fat substance contents, and pH were the most influential characteristics for sample discrimination according to cheese type. A plausible explanation may be the differences in milk chemical composition between three animal species, namely cows, sheep, and goats and for the manufacture procedure and ripening. This is the very first report on the proximate analysis of these, largely ignored, chesses aiming to simulate interest for further study and production valorization.

Microbial communities and main features of labneh Ambaris, a traditional Lebanese fermented goat milk product

Labneh Ambaris is a traditional Lebanese dairy product typically made using goat milk in special earthenware jars. Its production is characterized by the regular additions of milk and coarse salt, all while draining the whey throughout a process that lasts for a minimum of 2 mo. In this study, 20 samples of labneh Ambaris, all produced by spontaneous fermentation, were studied. They were collected at the end of fermentation from different regions in Lebanon. Physicochemical and sensory properties were studied and microbial diversity was analyzed using culture-dependent and independent techniques. The V3-V4 region of the 16S rRNA gene and the ITS2 region were sequenced by DNA metabarcoding analyses for the identification of bacteria and yeast communities, respectively. Out of 160 bacterial and 36 fungal taxa, 117 different bacterial species and 24 fungal species were identified among all labneh Ambaris samples studied. The remaining ones were multi-affiliated and could not be identified at the species level. Lactobacillus was the dominant bacterial genus, followed by Lentilactobacillus, Lactiplantibacillus, Lacticaseibacillus, and Lactococcus genera, whereas Geotrichum and Pichia were the dominant fungal genera. The 20 samples tested had varying levels of salt, protein, and fat contents, but they were all highly acidic (mostly having a pH < 4). According to the sensory scores generated by classical descriptive analysis, all samples were described as having basic similar characteristics such as goat smell and flavor, but they could be differentiated based on various intensities within the same descriptors like salty and acidic. This work could be considered as a base toward obtaining a quality label for labneh Ambaris.

Descriptive Characteristics and Cheesemaking Technology of Greek Cheeses Not Listed in the EU Geographical Indications Registers

Greece has a variety of cheeses that are registered as protected designation of origin and protected geographical indications, and many others that are produced in a traditional way, without such registration. This article aims to describe the characteristics of these cheeses, which do not bear a certification of geographical indication, in order to increase their significance. Therefore, in this work, the scientific data published about the history, production, composition, and other specific properties of some milk cheeses (Kariki, hard Xinotyri, soft Xinotyri, Kefalotyri, Kashkaval Pindos, Graviera, Manoura Sifnos, Teleme, Tsalafouti, Tyraki Tinou, Ladotyri Zakynthou, Touloumotyri, and Melichloro) and whey cheeses (Anthotyros, Myzithra, and Urda) are presented. This information may contribute to their better promotion and recognition, protecting their heritage, and supporting the local economy.

Raw goat's milk fermented Anbaris from Lebanon: insights into the microbial dynamics and chemical changes occurring during artisanal production, with a focus on yeasts

Anbaris is a raw goat milk product naturally fermented in terracotta jars. The aim of this research paper was to follow the dynamics underlying an artisanal production to understand the concomitant evolution of the microbial populations in relation to the chemical changes occurring within the product, make sure of the sanitary conditions prevailing during the production and uncover for the first time its culturable yeast populations. Throughout the fermentation process, Anbaris was endowed with high acidity and included high microbial populations counts of LAB and yeasts that were rapidly installed within the product and maintained as regular new milk additions were made, contributing to lipolytic and proteolytic activities. Salt content varied according to the arbitrary salt additions made during the process but was high in the end product while protein and fat contents varied inversely to moisture. Frequent additions of Enterobacteriaceae and Coliforms contaminated milk samples seemingly fueled a contamination of the product during its manufacturing and in the final fresh Anbaris. Seven species of culturable yeasts, Pichia kudriavzevii, Kluyveromyces marxianus, Rhodotorula mucilaginosa, Saccharomyces cerevisiae, Debaryomyces hansenii, Candida parapsilosis and Kazachstania exigua were found during the production. The first two dominated the process in terms of frequency of occurrence and abundance at the different stages and might be signature species of the product. The same lineage of K. marxianus isolates was maintained throughout the fermentation and sample specific patterns were observed. Strains of this species exhibited low diversity within our product, and more globally in the Lebanese dairy products we studied.

Insights into the diversity of cow milk production systems on the fringes of coastal cities in West Africa: A case study from Benin

In sub-Saharan Africa, rapid population growth, urbanization, increasing incomes, and changing dietary preferences are the main drivers of the rising demand for livestock products, especially fresh milk and derived products. To meet this demand, there is an increasing number of dairy cattle farms in the densely populated coastal zone of Benin, where the country's largest city and commercial capital Cotonou is located. To identify and characterize the peri-urban dairy production systems in this region, 190 cattle keepers were surveyed, using the snowball sampling method, in four municipalities neighboring Cotonou. Information on their socio-economic characteristics, cattle herd sizes, and herd management practices were collected through questionnaire-based face-to-face interviews. Factor analysis of mixed data followed by hierarchical clustering on principal components, implemented in R statistical software, were applied to classify the surveyed farms into homogeneous groups. Results revealed six types of peri-urban dairy cattle farms differing mainly in their cows' breeds, herd sizes, and daily amount of milk produced. Most herds (88%) were owned by urban dwellers, mainly civil servants and traders, who entrusted the management of their cattle to hired professional herders. Irrespective of farm type, cows were of local taurine (65%) or Sahelian zebu (35%) breeds and were exclusively fed on communal natural pasture. Mineral supplementation was provided to the animals on 42% of farms, with significant variation across farm types. About 45% of the farms integrated cattle production with other agricultural activities, including coconut plantations (22%), where cow manure was used as fertilizer. The herd structure was similar across farm types, with average proportions of cows and heifers ranging from 37.6 to 47.5% and from 13.1 to 19.7%, respectively. With significant differences across farm types, the produced milk was either transformed into traditional cheese (32% of farms) or sold raw (85%). Milk and cheese sales represented 84% of the total farm income for three out of the six farm types. In the current context of rapid urbanization, communal grazing lands alone cannot provide sufficient feed to support increased milk production. In addition to improved feeding strategies, herd structure should be balanced in terms of the ratio between milk-producing and non-producing animals.

Yeasts in different types of cheese

Yeasts constitute an important part of cheeses, and especially the artisanal ones. The current study reviews the occurrence of yeasts in different cheese varieties and the role of yeasts in cheesemaking process. The use of molecular methods for identification and strain typing has extended the knowledge for yeast diversity in cheeses. For the study of the occurrence of yeasts in different cheese types, seven categories are used, that is: 1) hard, 2) semi-hard, 3) soft, which includes soft pasta-filata and whey cheeses, 4) white brined cheeses, 5) mould surface ripened, 6) bacterial surface ripened cheeses, and 7) blue cheeses. For some cheese types, yeasts are the main microbial group, at least for some part of their ripening process, while for some other types, yeasts are absent. Differences between industrially manufactured cheeses and artisanal cheeses have specified. Artisanal cheeses possess a diverse assortment of yeast species, mainly belonging to the genera Candida, Clavisporalus, Cryptococcus, Debaryomyces, Geotrichum, Issatchenkia, Kazachstania, Kluyveromyces, Kodemaea, Pichia, Rhodotorula, Saccharomyces, Saturnispora, Torulaspora, Trichosporon, Yarrowia and ZygoSaccharomyces. The role of the yeasts for selected cheeses from the seven cheese categories is discussed.

Metabolomics as a marketing tool for geographical indication products: a literature review

Geographical indication (GI) is used to identify a product's origin when its characteristics or quality are a result of geographical origin, which includes agricultural products and foodstuff. Metabolomics is an “omics” technique that can support product authentication by providing a chemical fingerprint of a biological system, such as plant and plant-derived products. The main purpose of this article is to verify possible contributions of metabolomic studies to the marketing field, mainly for certified regions, through an integrative review of the literature and maps produced by VOSviewer software. The results indicate that studies based on metabolomics approaches can relate specific food attributes to the region’s terroir and know-how. The evidence of this connection, marketing of GIs and metabolomics methods, is viewed as potential tool for marketing purposes (e.g., to assist communication of positive aspects and quality), and legal protection. In addition, our results provide a taxonomic categorization that can guide future marketing research involving metabolomics. Moreover, the results are also useful to government agencies to improve GIs registration systems and promotion strategies.

Sensory Profile of Chihuahua Cheese Manufactured from Raw Milk

Chihuahua cheese is a local artisanal cheese traditionally produced from raw milk. When this cheese is produced with pasteurized milk, cheesemakers complain that there are differences in taste and aroma as compared with traditional manufacturing. This work aimed to obtain a descriptive sensory analysis of Chihuahua cheese manufactured with raw milk under traditional conditions. Samples were collected in five cheese dairies at two different seasons (summer and autumn), and a Quantitative Descriptive Sensorial Analysis was done by a panel of trained judges. For aroma descriptors, cooked descriptor showed differences between dairies, and whey was different among dairies and sampling seasons (P<0.01); diacetyl, fruity (P<0.01), as well as free fatty acids, nutty and sulphur (P<0.05) descriptors varied between seasons. For flavour descriptors, bitter perception was different between dairies and seasons (P<0.01). Salty and creamy cheese was also different among dairies (P<0.01). A Principal Component Analysis for differences among dairies and sampling season demonstrated that the first three components accounted for 90% of the variance; variables were more affected by the sampling seasons than by the geographical location or if the dairy was operated by Mennonites. Chihuahua cheese sensorial profile can be described as a semi-matured cheese with a bitter flavour, slightly salted, and with a cream flavour, with aroma notes associated with whey and sour milk. Principal Component Analysis demonstrated season influence on flavour and aroma characteristics.

Microbiological characterization using combined culture dependent and independent approaches of Casizolu pasta filata cheese

AIMS

Casizolu is a traditional Sardinian (Italy) pasta filata cheese made with cow raw milk belonging to Sardo-Modicana and/or Bruno-Sarda breeds added with natural whey starter. This work aims to describe the traditional technology of this product and to evaluate the microbial groups/species involved in the first month of ripening.

METHODS AND RESULTS

Raw milk, curd after stretching and Casizolu cheese samples from two different farmsteads were subjected to enumeration of microbial groups, isolation and genotypic characterization of isolates and PCR temporal temperature gel electrophoresis (TTGE) analysis. The counts of lactobacilli and lactococci groups in raw milk were about 5-6 log UFC ml(-1) of milk. These counts tended to increase in curd and cheeses, reaching values higher than 8 log UFC g(-1) of cheese. Culture dependent and independent approaches employed in this work highlighted the fundamental role of Lactococcus lactis subsp. lactis, Streptococcus thermophilus and Lactobacillus paracasei in the manufacture and ripening of Casizolu cheese. Other species frequently isolated were Enterococcus durans, Enterococcus faecium, Enterococcus italicus while Enterococcus lactis, Streptococcus parauberis, Lactobacillus plantarum, Lactobacillus pentosus, Lactobacillus brevis, Lactobacillus fermentum and Lactococcus raffinolactis were isolated occasionally.

CONCLUSIONS

Lactococcus lactis subsp. lactis, Strep. thermophilus and Lact. paracasei were the principal bacterial species involved in the Casizolu cheese manufacturing and ripening. For the first time, Ent. italicus and Ent. lactis were isolated in the pasta filata cheese.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study shows the first data on microbial groups and species involved in the manufacture of Casizolu cheese and highlights the role of Lact. paracasei and Enterococcus spp. from the earliest stages of ripening cheese; furthermore, provides evidence that raw milk cheese is a source of new strains and therefore a reservoir of microbial biodiversity.

Wooden Tools: Reservoirs of Microbial Biodiversity in Traditional Cheesemaking

Today, wooden shelves are used for the ripening of about 500,000 tons of cheese per year in Europe, including about 350,000 tons in France, such as most of the famous cheeses with the protected designation of origin (PDO), e.g., Comté, Reblochon, Beaufort, Munster, Cantal, and Roquefort. For some PDO cheeses, the use of wooden tools is mandatory. Many cheesemakers believe that wooden tools improve the organoleptic and typical characteristics of their final products. Wood is a natural and sustainable material which has been used for centuries in traditional cheese production in a wide variety of forms (vats, shelves, and packaging). Wood is important in the cheesemaking process, interacting with the milk in vats or with the cheeses placed on shelves for ripening. Wood is viable due to its ability to exchange water but, above all, because it is covered by a rich microbial biofilm. As wood is porous and difficult to clean, the European Commission regularly highlights the question of its safety when in contact with food and calls for deeper scientific investigation. In this review, knowledge about the multiple technological roles of wood in dairy technology is discussed. The crucial role of wood as a reservoir of microbial biodiversity for traditional cheeses is reviewed, along with results of safety assessments. As a conclusion, the numerous questions remaining about this natural inoculating system are discussed.

Interannual and geographical reproducibility of the nutritional quality of milk fat from commercial grazing flocks

The objective of the present work was to study the differences in the fatty acid (FA) composition of raw sheep milk fat under commercial milk production conditions throughout lactation, in two consecutive years. Particular attention was placed on the C18:2cis-9,trans-11 isomer, C18:1trans-11 acid, and unsaturated FA as the feeding regimen of 10 commercial flocks of latxa dairy sheep changed from indoor feeding to part-time grazing conditions (from early spring) as traditionally practiced in the Basque Country (Northern Spain). Farms located at an altitude of between 600 and 700 m, in two different geographical areas with different rainfall were selected. Milk samples were collected monthly from late January (indoor feeding) until mid-, or end of, June (outdoor feeding), during two consecutive years. In spite of some interannual variability (most likely due to large differences in rainfall), the evolution of individual FA throughout lactation was comparable between years, indicating that it was reproducible under commercial milk production conditions. The average concentrations of C18:2cis-9,trans-11 isomer and C18:1trans-11 acid in milk from the commercial flocks increased about 200% during the transition period (end of March or early April until May), from indoor feeding (late January or early February until the end of March) to the outdoor period (early May to mid-June), remaining constant during the outdoor period (27·53 ± 9·32 μmol/g fat and 71·58 ± 20·53 μmol/g fat, respectively). Non-atherogenic FA comprised approximately 50% of all saturated FA at any time during lactation, whereas the milk atherogenicity index decreased significantly during the outdoor period. The Trolox-equivalent antioxidant capacity of the water-soluble milk fraction did not appear to be influenced by feeding management. The FA composition of cheeses made during the second year with milk from the indoor or outdoor periods reflected those of the corresponding milks. A principal components analysis clearly showed that differences in the milk FA composition were primarily due to outdoor grazing, with very little contribution from the geographical zone or the year.