Diversity of species within Aspergillus niger clade, currently represented by A. niger sensu stricto and A. welwitshiae, was investigated combining three-locus gene sequences, Random Amplified Polymorphic DNA, secondary metabolites profile and morphology. Firstly, approximately 700 accessions belonging to this clade were investigated using calmodulin gene sequences. Based on these sequences, eight haplotypes were clearly identified as A. niger (n = 247) and 17 as A. welwitschiae (n = 403). However, calmodulin sequences did not provide definitive species identities for six haplotypes. To elucidate the taxonomic position of these haplotypes, two other loci, part of the beta-tubulin gene and part of the RNA polymerase II gene, were sequenced and used to perform an analysis of Genealogical Concordance Phylogenetic Species Recognition. This analysis enabled the recognition of two new phylogenetic species. One of the new phylogenetic species showed morphological and chemical distinguishable features in comparison to the known species A. welwitschiae and A. niger. This species is illustrated and described as Aspergillus vinaceus sp. nov. In contrast to A. niger and A. welwitschiae, A. vinaceus strains produced asperazine, but none of them were found to produce ochratoxin A and/or fumonisins. Sclerotium production on laboratory media, which does not occur in strains of A. niger and A. welwitschiae, and strictly sclerotium-associated secondary metabolites (14-Epi-hydroxy-10,23-dihydro-24,25-dehydroaflavinine; 10,23-Dihydro-24,25-dehydroaflavinine; 10,23-Dihydro-24,25-dehydro-21-oxo-aflavinine) were found in A. vinaceus. The strain type of A. vinaceus sp. nov. is ITAL 47,456 (T) (=IBT 35556).
Aspergillus section Flavi is a fungal group that is important in food because it contains spoilage and potentially aflatoxigenic species. Aflatoxins are metabolites that are harmful to human and animal health and have been recognized as the primary natural contaminant in food. Therefore, recognizing the biodiversity of this group in food is necessary to reduce risks to public health. Our study aimed to investigate the diversity of Aspergillus section Flavi isolated from Brazilian foodstuffs such as cassava, sugarcane, black pepper, paprika, Brazil nuts, yerba-mate, peanuts, rice, and corn. A polyphasic approach integrating phenotypic data and multilocus genotypic analyses (CaM, BenA, and RPB2) was performed for 396 strains. Two new species in the Aspergillus subgenus Circumdati section Flavi are proposed using maximum-likelihood analysis, Bayesian inference, and coalescence-based methods: Aspergillus saccharicola sp. nov. and Aspergillus annui sp. nov. A. saccharicola sp. nov. belongs to the series Flavi, is a potentially aflatoxigenic species (B1, B2, G1, and G2), closely related to Aspergillus arachidicola, and was found mostly in sugarcane. A. annui sp. nov. was isolated from samples of sweet paprika. To accommodate A. annui sp. nov., a new series Annuorum was proposed.
2 September 2022 in International Journal of Food Microbiology
This article discusses advances in molecular technologies for detecting foodborne pathogens, specifically Listeria monocytogenes and Salmonella. Although traditional detection methods are reliable, they are time- and labor-intensive. On the other hand, molecular methods include polymerase chain reaction (PCR), quantitative real-time PCR (qPCR), and next-generation sequencing (NGS), which enable rapid, specific, and sensitive detection of pathogens. The introduction of such procedures has significantly improved food safety testing and monitoring. Although challenges such as accessibility and cost remain, future developments in molecular diagnostics will lead to greater implementation in improving pathogen management throughout the food supply chain.
Foods that are fermented have a crucial role in global diets, these foods benefit from the process of fermentation, which enhances nutrition, flavor, and safety through the use of probiotics, anti-aging compounds, and antibiotics. Traditional fermentation is based on the spontaneous activity of microorganisms, while modern methods utilize defined cultures for consistency. The microorganisms in cheese are important for the flavor and texture of the product. These microorganisms are either non-starter or starter bacteria, yeast, and mold. The advances in sequencing technology have facilitated an increase in our understanding of these communities and their contribution to the quality and safety of cheese. Despite the health benefits of fermented dairy products, such as yogurt, they can pose a risk of contamination with pathogens. New methods of management and sequencing are crucial to ensuring the safety and quality of fermented foods, combining traditional methods with modern advances.