Project description:The aim of this study was to identify and compare surface mycobiota of traditional and industrial Croatian dry-fermented sausage Kulen, especially toxicogenic species, and to detect contamination with mycotoxins recognized as the most important for meat products. Identification of mould species was performed by sequence analysis of beta- tubulin and calmodulin gene, while the determination of mycotoxins aflatoxin B1 (AFB1), ochratoxin A (OTA), and cyclopiazonic acid (CPA) was carried out using the LC-MS/MS (liquid chromatography-tandem mass spectrometry) method. The results showed a significantly higher number of mould isolates and greater species (including of those mycotoxigenic) diversity in traditional Kulen samples in comparison with the industrial ones. P. commune, as a potential CPA-producer, was the most represented in traditional Kulen (19.0%), followed by P. solitum (16.6%), which was the most represented in industrial Kulen samples (23.8%). The results also showed that 69% of the traditional sausage samples were contaminated with either CPA or OTA in concentrations of up to 13.35 µg/kg and 6.95 µg/kg, respectively, while in the industrial samples only OTA was detected (in a single sample in the concentration of 0.42 µg/kg). Mycotoxin AFB1 and its producers were not detected in any of the analysed samples (<LOD).
Project description:No information is available in the literature about the influence of temperature (T) on Penicillium and Aspergillus spp. growth and mycotoxin production on cheese rinds. The aim of this work was to: (i) study fungal ecology on cheese in terms of T requirements, focusing on the partitioning of mycotoxins between the rind and mycelium; and (ii) validate predictive models previously developed by in vitro trials. Grana cheese rind blocks were inoculated with A. versicolor, P. crustosum, P. nordicum, P. roqueforti, and P. verrucosum, incubated at different T regimes (10-30 °C, step 5 °C) and after 14 days the production of mycotoxins (ochratoxin A (OTA); sterigmatocystin (STC); roquefortine C (ROQ-C), mycophenolic acid (MPA), Pr toxin (PR-Tox), citrinin (CIT), cyclopiazonic acid (CPA)) was quantified. All the fungi grew optimally around 15-25 °C and produced the expected mycotoxins (except MPA, Pr-Tox, and CIT). The majority of the mycotoxins produced remained in the mycelium (~90%) in three out of five fungal species (P. crustosum, P. nordicum, and P. roqueforti); the opposite occurred for A. versicolor and P. verrucosum with 71% and 58% of STC and OTA detected in cheese rind, respectively. Available predictive models fitted fungal growth on the cheese rind well, but validation was not possible for mycotoxins because they were produced in a very narrow T range.
Project description:Cheese represents a dairy product extremely inclined to fungal growth and mycotoxin production. The growth of fungi belonging to Aspergillus, Penicillium, Fusarium, Claviceps, Alternaria, and Trichoderma genera in or on cheese leads to undesirable changes able to affect the quality of the final products. In the present investigation, a total of 68 types of commercial and traditional Slovak cheeses were analyzed to investigate the occurrence of fungal metabolites. Altogether, 13 fungal metabolites were identified and quantified. Aflatoxin M1, the only mycotoxin regulated in milk and dairy products, was not detected in any case. However, the presence of metabolites that have never been reported in cheeses, such as tryptophol at a maximum concentration level from 13.4 to 7930 µg/kg (average: 490 µg/kg), was recorded. Out of all detected metabolites, enniatin B represents the most frequently detected mycotoxin (0.06-0.71 µg/kg) in the analyzed samples. Attention is drawn to the lack of data on mycotoxins' origin from Slovak cheeses; in fact, this is the first reported investigation. Our results indicate the presence of fungal mycotoxin contamination for which maximum permissible levels are not established, highlighting the importance of monitoring the source and producers of contamination in order to protect consumers' health.
Project description:Canastra cheese is the most well-known artisanal cheese produced in Brazil. Although its production includes a step to remove fungi from the cheese surface, in recent years some cheesemakers have preserved the autochthonous fungi grown during ripening due to an interest in the sensory characteristics attributed to these microorganisms. In this work, the mycobiota of artisanal cheeses produced in the Canastra region was characterized based on ITS marker gene analysis. A total of 96 artisanal cheeses from 16 different farms across 9 cities were collected during two different periods (dry and wet seasons). The Canastra cheese mycobiota was significantly impacted by the season, the city of production and the farm but altitude did not affect the fungal community of the cheeses analyzed. Debaryomyces prosopidis was most abundant in the majority of samples across both seasons. During the wet season, Trichosporon asahii, Kluyveromyces lactis and Fusarium solani were the next most abundant species, followed by Torulaspora delbrueckii and Acremonium citrinum. These results highlight the importance of manufacturing practices and seasonality on the fungal composition of Canastra cheeses. These insights are particularly important in light of recent new regulation in Brazil, removing previous obstacles for surface fungi to persist on cheese. These new regulations will allow new approaches to cheese production, and ultimately, novel products.
Project description:Cheese is one of the traditional fermented dairy products in Xinjiang, China. Due to its geographical location and regional feature this type of cheese harbors certain regional characteristics. To investigate these, here Illumina MiSeq high-throughput sequencing technology was used to target the v4-v5 interval to analyze the composition of fungal flora in Xinjiang traditional cheese. Our results showed the fungal flora of this cheese is mainly composed of Pichia (65.20%), Kazachstania (9.05%), Galactomyces (7.21%), Zygosaccharomyces (6.56%), Torulaspora (3.13%), Dipodascus (2.11%) and Ogataea (1.64%) belonging to the Ascomycota. PcoA (Principal Co-ordinates Analysis) and an UPGMA (unweighted pair-group method with arithmetic means) based on the OTUs (Optical Transform Unit) horizontal-weighted UniFrac distances, revealed some differences in fungal community structure among 17 cheese samples. At the OTU level, nine dominant OTUs were found in all the samples, for which Pichia was the most important fungal group. Building on this, the moisture content (23.20-59.22%), water distribution, and salt content (1.13-4.84%) in cheese were also determined. We found that six of the seven dominant fungal genera had specific correlations with the above physical and chemical variables, with only Ogataea uncorrelated with any variables. The results provide a theoretical basis for the development and use of cheese microbial resources in Xinjiang, China.Supplementary informationThe online version contains supplementary material available at 10.1007/s12088-021-00967-x.
Project description:Background and objectivesThe microbial communities of traditional milk-based food are of great importance in its manufacturing process, especially when using raw milk with natural cultures. Liqvan (Lighvan or Levan) is a traditional Iranian buried cheese, which is made from raw ewe's milk without a starter addition. The aim of this study was to explore the fungal active population during this cheese manufacturing process by comparing DNA and RNA based culture independent method Denaturing Gradient Gel Electrophoresis (DGGE).Materials and methodsFour samples of each milk, curd and ripened cheese were collected from Liqvan village located in East Azerbaijan province of Iran. Total DNA and RNA of each sample were extracted and PCR amplicons of D1 region of 26S rRNA gene was targeted for DGGE analysis. This method applied at both DNA and RNA levels in order to examine which taxonomic groups of fungi are active at each step of ripening.ResultsDGGE profiles of yeast amplicons showed different results between extracted DNA and RNA during ripening process. However, the main group that is present in all stages of ripening process belongs to the genus Candida although Kluyveromyces, Pichia, Galactomyces, Saccharomyces and Cryptococcus are most abundant fungi.ConclusionAs no starter culture added to Liqvan cheese it seems fungal diversity are mainly rely on the indigenous microbiota of milk. Furthermore, the percentage of the dominant fungal genera from the total sequences differed among DNA and cDNA libraries.
Project description:Forty-three species and variety belonging to 15 genera were collected from 30 strawberry fruit samples on Glucose-Czapek's agar medium. Among them, Aspergillus flavus, Aspergillus niger and Penicillium citrinum were the most frequent species recovered from 53.3%, 70.0% and 50.0% of the samples, respectively. According to the ITS rDNA sequence, we confirmed the morphological identification result. Moreover, aflatoxin biosynthesis gene omt-A was detected in A. flavus, while Aopks gene was found in A. niger. Interestingly, we could not detect any aflatoxin or ochratoxin biosynthesis genes in the P. citrinum strain. The concentration of detected aflatoxin was 3.5 ppb produced by A. flavus, while A. niger gave 4.1 ppb as ochratoxin. A. flavus was the most pectinase producer among the selected strains, and the highest amount was obtained at 30°C after 6 days of incubation with initial medium pH 8.
Project description:Karst caves are distinctive ecosystems that have limited nutrients, darkness, low to moderate temperatures, and high moisture levels, which allow for a diverse range of fungal communities to thrive. Despite their significance, little is understood about the fungi found in karst caves in Thailand. In 2019, we studied the cultured mycobiota from five substrate types (air, water, rock, soil/sediment, and organic debris) in two karst caves (Le Stegodon and Phu Pha Phet Caves) of the Satun UNESCO Global Geopark, southern Thailand. A cumulative count of 829 distinct fungal morphological types was identified, encompassing 319 fungal culturable were observed. Based on preliminary analyses of the internal transcribed spacer (ITS) sequence using BLAST searches, the most common phylum among the fungal morphotypes was Ascomycota, harboring 282 species in 91 genera, 93.4% of which were distributed in the classes Eurotiomycetes, Sordariomycetes, and Dothideomycetes. The most common fungal genera identified in the two karst caves were Aspergillus, Penicillium, Cladosporium, Talaromyces, Xylaria, and Trichoderma, with 45, 41, 24, 14, 14, and 6 species identified, respectively. Discovering fungi in Thai karst caves highlights the extensive fungal diversity in the Satun UNESCO Global Geopark, implying undiscovered species, and emphasizing the need for comprehensive investigations in other unexplored Thai karst caves.