Lactic Acid Bacteria Fermentation and Endopeptidase Treatment Improve the Functional and Nutritional Features of Arthrospira platensis

This study aimed at investigating the effect of fermentation and enzymatic treatment on the degree of proteolysis of wet (WB), dried at low temperature (DB), and freeze-dried Spirulina (LB) proteins that affect the nutritional (e.g., amino acid content and profiles, and protein digestibility) and functional (e.g., antioxidant and antimicrobial activities) properties. The desiccation treatments influenced the unprocessed Spirulina characteristics because, compared with that in WB, peptides and free amino acids content was 73% lower in DB and 34% higher in LB. An integrated approach, including chromatographic and electrophoresis analyses, was used to evaluate the effect of the different bioprocessing options on protein profiles, release of peptides and amino acids, and the overall protein digestibility. Compared with the application of fermentation with the selected Lactiplantibacillus plantarum T0A10, the treatment with the endopeptidase Alcalase®, alone or combined, determined the most intense proteolysis. Moreover, the treatment with Alcalase® of LB allowed the release of potentially bioactive compounds that are able to inhibit Penicillium roqueforti growth, whereas the combination of fermentation with L. plantarum T0A10 and Alcalase® treatment increased Spirulina antioxidant properties, as determined by the scavenging activity toward ABTS radical (up to 60%) and antimicrobial activity against food pathogen Escherichia coli.

Molds and Aflatoxins in Traditional Moldy Civil Cheese: Presence and Public Health Concerns

The purpose of this study was to detect the mold biota, the contamination levels of total aflatoxin (AFB1, AFB2, AFG1, AFG2) and aflatoxin M1 (AFM1) in moldy civil cheese. A total of 100 moldy civil cheese were collected from randomly selected retailers. Mold biota was determined with conventional and ITS sequence analysis, and Aflatoxin (AF) analysis was performed usingEnzyme-Linled Immunosorbent Assay (ELISA). In the analyzed samples, Penicillium roqueforti (100%) was isolated as the dominant species followed by P. verrucosum (83%), Aspergillus flavus (17%). Fifteen (15 %) of moldy civil cheese samples contained AF with levels ranging from 12 to 378 ng/kg.Likewise, AFM1 was found in 25 (25 %) of samples (ranging from 5.46 to 141.56 ng/kg), among which 5 (5 %) were above the legal limits. Considering the presence of A. flavus, total AF and AFM1 contamination in the analyzed cheese samples it could be emphasized that moldy civil cheese might pose a hazard for public health.

Differentiation of Penicillium roqueforti from Closely Related Species Contaminating Cheeses and Dairy Environment

Currently, Penicillium roqueforti and the closely related P. carneum and P. paneum are identified based on their macromorphology, micromorphology, and molecular properties, the determination of which involves time-consuming procedures. Culture collections focused on dairy isolates of P. roqueforti require quick and efficient tools for routine applications to identify the (a) taxonomy affiliation and (b) morphological properties of strains that influence the sensory properties of blue-veined cheeses. Here, we assessed the morphological variability of P. roqueforti, P. carneum, P. paneum, and P.crustosum on artificial, Edam-like, and Roquefort-like media. Molecular tools were used to test P. roqueforti strains and clones effectively. A novel primer, PrsF, was tested for specificity within strains and isolates of P. roqueforti compared to P. carneum, P. paneum, and P. crustosum. The results reveal that PrsF was specific to the P. roqueforti samples and did not amplify the other tested Penicillium species. Identification based simultaneously on the specificity of the PrsF primer pair and cultivation of P. roqueforti strains on Roquefort-like medium represents an effective method for expanding the collections and practical use of P. roqueforti in the dairy industry.

New Cytoplasmic Virus-Like Elements (VLEs) in the Yeast Debaryomyces hansenii

Yeasts can have additional genetic information in the form of cytoplasmic linear dsDNA molecules called virus-like elements (VLEs). Some of them encode killer toxins. The aim of this work was to investigate the prevalence of such elements in D. hansenii killer yeast deposited in culture collections as well as in strains freshly isolated from blue cheeses. Possible benefits to the host from harboring such VLEs were analyzed. VLEs occurred frequently among fresh D. hansenii isolates (15/60 strains), as opposed to strains obtained from culture collections (0/75 strains). Eight new different systems were identified: four composed of two elements and four of three elements. Full sequences of three new VLE systems obtained by NGS revealed extremely high conservation among the largest molecules in these systems except for one ORF, probably encoding a protein resembling immunity determinant to killer toxins of VLE origin in other yeast species. ORFs that could be potentially involved in killer activity due to similarity to genes encoding proteins with domains of chitin-binding/digesting and deoxyribonuclease NucA/NucB activity, could be distinguished in smaller molecules. However, the discovered VLEs were not involved in the biocontrol of Yarrowia lipolytica and Penicillium roqueforti present in blue cheeses.