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The impacts of salt reduction by NaCl sprinkling and NaCl substitution with 25% calcium lactate on the quality of blue cheese were evaluated. Sprinkling reduced sodium content by 35% and substitution reduced sodium content by 47%. The salt‐reduced cheeses had a higher calcium content, vitamin B2, B6, and B12 levels, and a higher rate of proteolysis. Sensory and texture profile analysis found that the salt‐reduced cheeses had a less salty taste and were less firm. These methods enabled significant salt reduction but had negative effects on the cheese properties, and so further work is needed to diminish these effects. [ABSTRACT FROM AUTHOR]

Penicillium roqueforti is a fungal starter culture used for the production of blue-veined cheeses, such as Roquefort, Gorgonzola, Stilton, Cabrales, and Danablue. During ripening, this species grows in the veins of the cheese, forming the emblematic blue-green color and establishing the characteristic flavor owin to its biochemical activities. P. roqueforti synthesizes a diverse array of secondary metabolites, including the well-known compounds roquefortine C, clavine alkaloids, such as isofumigaclavine A and B, mycophenolic acid, andrastin A, and PR-toxin. This review provides an in-depth exploration of P. roqueforti's secondary metabolites, focusing on their biosynthetic pathways, the gene clusters responsible for their production, and their bioactivities. The presence of these compounds in blue cheeses is also reviewed. Furthermore, the silent clusters and the potential of P. roqueforti for producing secondary metabolites were discussed. The review highlights recently identified metabolites, including sesterterpenoids; tetrapeptides, D-Phe-L-Val-D-Val-L-Tyr, and D-Phe-L-Val-D-Val-L-Phe; cis-bis(methylthio)silvatin; and the 1,8-dihydroxynaphthalene (DHN)-melanin precursor, scytalone. Additionally, a gene cluster for DHN–melanin biosynthesis is presented. Finally, a revised cluster for roquefortine C biosynthesis comprising three rather than four genes is proposed. [ABSTRACT FROM AUTHOR]

Polyamine intake has been reported to help extend the lifespan of animals. Fermented foods contain high concentrations of polyamines, produced by fermenting bacteria. Therefore, the bacteria, isolated from fermented foods that produce large amounts of polyamines, are potentially used as a source of polyamines for humans. In this study, the strain Levilactobacillus brevis FB215, which has the ability to accumulate approximately 200 µM of putrescine in the culture supernatant, was isolated from fermented foods, specifically the Blue Stilton cheese. Furthermore, L. brevis FB215 synthesized putrescine from agmatine and ornithine, which are known polyamine precursors. When cultured in the extract of Sakekasu, a byproduct obtained during the brewing of Japanese rice wine containing high levels of both agmatine and ornithine, L. brevis FB215 grew to OD600 = 1.7 after 83 h of cultivation and accumulated high concentrations (~1 mM) of putrescine in the culture supernatant. The fermentation product also did not contain histamine or tyramine. The Sakekasu-derived ingredient fermented by the food-derived lactic acid bacteria developed in this study could contribute to increasing polyamine intake in humans. [ABSTRACT FROM AUTHOR]

Filamentous fungi are an important source of natural products. The mold Penicillium roqueforti, which is well-known for being responsible for the characteristic texture, blue-green spots, and aroma of the so-called blue-veined cheeses (French Bleu, Roquefort, Gorgonzola, Stilton, Cabrales, and Valdeón, among others), is able to synthesize different secondary metabolites, including andrastins and mycophenolic acid, as well as several mycotoxins, such as Roquefortines C and D, PR-toxin and eremofortins, Isofumigaclavines A and B, festuclavine, and Annullatins D and F. This review provides a detailed description of the biosynthetic gene clusters and pathways of the main secondary metabolites produced by P. roqueforti, as well as an overview of the regulatory mechanisms controlling secondary metabolism in this filamentous fungus. [ABSTRACT FROM AUTHOR]

Penicillium roqueforti is a fungal starter culture used for the production of blue-veined cheeses, such as Roquefort, Gorgonzola, Stilton, Cabrales, and Danablue. During ripening, this species grows in the veins of the cheese, forming the emblematic blue-green color and establishing the characteristic flavor owin to its biochemical activities. P. roqueforti synthesizes a diverse array of secondary metabolites, including the well-known compounds roquefortine C, clavine alkaloids, such as isofumigaclavine A and B, mycophenolic acid, andrastin A, and PR-toxin. This review provides an in-depth exploration of P. roqueforti’s secondary metabolites, focusing on their biosynthetic pathways, the gene clusters responsible for their production, and their bioactivities. The presence of these compounds in blue cheeses is also reviewed. Furthermore, the silent clusters and the potential of P. roqueforti for producing secondary metabolites were discussed. The review highlights recently identified metabolites, including sesterterpenoids; tetrapeptides, D-Phe-L-Val-D-Val-L-Tyr, and D-Phe-L-Val-D-Val-L-Phe; cis-bis(methylthio)silvatin; and the 1,8-dihydroxynaphthalene (DHN)-melanin precursor, scytalone. Additionally, a gene cluster for DHN–melanin biosynthesis is presented. Finally, a revised cluster for roquefortine C biosynthesis comprising three rather than four genes is proposed.

A heleomyzid fly Tephrochlamys rufiventris (Meigen, 1830), was reared from a form of blue cheese aging in a refrigerated, dark, aging room of a small northern California creamery. The third-instar larva is redescribed and the puparium is described for the first time.

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.

Blue cheese flavour development derives from complex biochemical reactions that depend on numerous factors including milk source, culture/strain selection, processing, and ripening conditions. Understanding volatile compound development during blue cheese ripening will help reduce production costs and facilitate quality improvements. Volatile compounds contribute to the characteristic flavours of the cheeses but ripening time predictions based on chemical data have proven difficult. The present study employed untargeted fingerprinting combined with linear and non-linear chemometric approaches to identify key volatiles for the modelling of Shenley Station blue cheese ripening times. Self-organizing maps and entropy-based feature selection along with partial least squares regression and variable identification coefficients were used to parse the linear and non-linear development behaviours of volatiles. The blue cheese ripening times were accurately modelled by twenty-three discriminant volatiles. The present study demonstrated that volatile fingerprints can be used to effectively model blue cheese ripening times using a non-linear chemometric approach.

Polyamine intake has been reported to help extend the lifespan of animals. Fermented foods contain high concentrations of polyamines, produced by fermenting bacteria. Therefore, the bacteria, isolated from fermented foods that produce large amounts of polyamines, are potentially used as a source of polyamines for humans. In this study, the strain Levilactobacillus brevis FB215, which has the ability to accumulate approximately 200 µM of putrescine in the culture supernatant, was isolated from fermented foods, specifically the Blue Stilton cheese. Furthermore, L. brevis FB215 synthesized putrescine from agmatine and ornithine, which are known polyamine precursors. When cultured in the extract of Sakekasu, a byproduct obtained during the brewing of Japanese rice wine containing high levels of both agmatine and ornithine, L. brevis FB215 grew to OD600 = 1.7 after 83 h of cultivation and accumulated high concentrations (~1 mM) of putrescine in the culture supernatant. The fermentation product also did not contain histamine or tyramine. The Sakekasu-derived ingredient fermented by the food-derived lactic acid bacteria developed in this study could contribute to increasing polyamine intake in humans.

Filamentous fungi are an important source of natural products. The mold Penicillium roqueforti, which is well-known for being responsible for the characteristic texture, blue-green spots, and aroma of the so-called blue-veined cheeses (French Bleu, Roquefort, Gorgonzola, Stilton, Cabrales, and Valdeón, among others), is able to synthesize different secondary metabolites, including andrastins and mycophenolic acid, as well as several mycotoxins, such as Roquefortines C and D, PR-toxin and eremofortins, Isofumigaclavines A and B, festuclavine, and Annullatins D and F. This review provides a detailed description of the biosynthetic gene clusters and pathways of the main secondary metabolites produced by P. roqueforti, as well as an overview of the regulatory mechanisms controlling secondary metabolism in this filamentous fungus.

The presence of areas with growth mold and their distribution in cheese matter are significant factors for blue cheese quality. Traditionally these parameters are evaluated by sensory profiling using experts' knowledge. Thus the assessment is subjective and performance time variate depends on current providing of experts services. Previous researches proof that methods of computer vision could help for fast and accurate analysis of quantity of mold on the blue cheese cut surface. The methods of statistical analysis also could support mold analysis in blue cheese in order to be evaluated the evenness of their distribution. The main purpose of current research is to propose an approach for automatic mold analysis in blue cheese using CVS (Computer Vision System) and software tools included in NI LabVIEW environment in order to perform complex analysis of mold growth. The selected blue cheese trademarks were: Bergader, Dorblu with 50% fat, Dorblu with 55% fat, Paladin ReginaBlu, and Steffel Gran Bavarese. Every sample is cut on slices and these slices are evaluated by experts and captured with digital camera in CVS. An upgraded CVS is used for data acquisition and a specially developed application in NI LabVIEW environment processes cheese images and presents reports for quantity of mold and its distribution using different grid size. Assessment of blue cheese quality is performed by experts using Likert scale for two parameters- quantity of mold and evenness of their distribution. This scale assign points for naturally described scores about blue cheese quality. A correlation analysis is performed for assessments of blue cheese quality received through computer analysis and experts estimation in order to be evaluated effectiveness of proposed approach. The results show that experts' estimation about quantity of mold strongly corresponds with calculated value using developed application (Pearsons' coefficient is ≈ 0.96) and experts' estimation about evenness of mold distribution also corresponds with calculated values (Pearsons' coefficient is ≈ 0.99) using grid size 4 x 4 and thresholding methods Inter-class variance and Clustering. It is observed that when the quantity of mold is very small (mean value below 1%) and standard deviation about its value is also small (below 0.3), then the calculated factor of evenness has high value because more of ROIs have also very small quantity of mold. The samples with high quantity of mold (in the range from 3% to 4%) are presented with high standard deviation (in the range from 1.5 to 3.5) which could be explained with presence of areas (ROIs) with quantity of mold smaller than mean value. As a conclusion the automatically reported values for quantity of mold and factor of evenness distribution are enough to support the control of quality of blue cheese regarding the mold presence and distribution. [ABSTRACT FROM AUTHOR]

Certain fungi can produce secondary metabolites that are toxic, mycotoxins. Two groups of cheeses where fungi are used for ripening are the blue-veined cheeses (Penicillium roqueforti) and the "soft-ripened" cheeses (P. camemberti). An enzyme-linked immunosorbent assay was used to screen for the mycotoxin roquefortine C (ROQC) in 202 samples of cheeses sold in the United States. Of these 152 were blue-veined cheeses, 46 were soft-ripened cheeses and 4 were other varieties of mould-ripened cheeses. ROQC was not detected in any of the soft-ripened cheeses, at a limit of detection of 1.8 µg/kg. ROQC was found in 151 of 152 blue-veined cheeses. The maximum level found was 6,630 µg/kg (median 903 µg/kg, average of positives 1430 µg/kg, limit of quantitation 6.9 µg/kg). These levels are consistent with the levels found previously in blue-veined cheeses in the United Kingdom and Europe, which have generally been considered non-hazardous for human consumption. [ABSTRACT FROM AUTHOR]

Sleep is a conserved and essential behavior, but its mechanistic and functional underpinnings remain poorly defined. Through unbiased genetic screening in Drosophila, we discovered a novel short-sleep mutant we named argus. Positional cloning and subsequent complementation, CRISPR/Cas9 knock-out, and RNAi studies identified Argus as a transmembrane protein that acts in adult peptidergic neurons to regulate sleep. argus mutants accumulate undigested Atg8a(+) autophagosomes, and genetic manipulations impeding autophagosome formation suppress argus sleep phenotypes, indicating that autophagosome accumulation drives argus short-sleep. Conversely, a blue cheese neurodegenerative mutant that impairs autophagosome formation was identified independently as a gain-of-sleep mutant, and targeted RNAi screens identified additional genes involved in autophagosome formation whose knockdown increases sleep. Finally, autophagosomes normally accumulate during the daytime and nighttime sleep deprivation extends this accumulation into the following morning, while daytime gaboxadol feeding promotes sleep and reduces autophagosome accumulation at nightfall. In sum, our results paradoxically demonstrate that wakefulness increases and sleep decreases autophagosome levels under unperturbed conditions, yet strong and sustained upregulation of autophagosomes decreases sleep, whereas strong and sustained downregulation of autophagosomes increases sleep. The complex relationship between sleep and autophagy suggested by our findings may have implications for pathological states including chronic sleep disorders and neurodegeneration, as well as for integration of sleep need with other homeostats, such as under conditions of starvation.

Quantity of mold Penicillium roqueforti in blue cheese is a significant factor for cheese quality. Therefore it is important to have abilities for fast and accurate assessment of molds’ quantity. Computer vision is popular as fast and not so expensive techniques for monitoring of cheese quality parameters. Segmentation algorithms are widely used for images analysis in order to extract specific objects from background. When the result of segmentation is binary image then the algorithms are known as thresholding algorithms. This paper presents an approach for evaluation the quantity of mold Penicillium roqueforti on cut surface of blue cheese, based on images processing with thresholding algorithms in HSI (Hue Saturation Intensity) color space. Four trademarks of blue cheese are used for experiments. The images of cut surfaces of examined blue cheese are processed with application developed in NI LabView environment. All images are processed also with algorithm for mold distribution analysis in RGB color space which uses manual thresholding. The results for mold Penicillium roqueforti quantity which are calculated using developed application and algorithm for mold distribution in RGB color space, are compared. It is performed a correlation analysis for quantity of mold Penicillium roqueforti calculated with developed application versus quantity calculated by algorithm for mold distribution analysis in RGB color space. The calculated correlation coefficients are high for intensity and hue components (about 0.9) which show that the results are statistically significant. Because of this, developed application could be used for automatic control of blue cheese quality. The results show that developed application could be used in blue cheese quality control. [ABSTRACT FROM AUTHOR]

Drosophila blue cheese (bchs) encodes a BEACH domain adaptor protein that, like its human homolog ALFY, promotes clearance of aggregated proteins through its interaction with Atg5 and p62. bchs mutations lead to age-dependent accumulation of ubiquitinated inclusions and progressive neurodegeneration in the fly brain, but neither the influence of autophagy on bchs-related degeneration, nor bchs’ placement in the autophagic hierarchy have been shown. We present epistatic evidence in a well-defined larval motor neuron paradigm that in bchs mutants, synaptic accumulation of ubiquitinated aggregates and neuronal death can be rescued by pharmacologically amplifying autophagic initiation. Further, pharmacological rescue requires at least one intact BEACH-containing isoform of the two identified in this study. Genetically augmenting a late step in autophagy, however, rescues even a strong mutation which retains only a third, non-BEACH containing isoform. Using living primary larval brain neurons, we elucidate the primary defect in bchs to be an excess of early autophagic compartments and a deficit in mature compartments. Conversely, rescuing the mutants by full-length Bchs over-expression induces mature compartment proliferation and rescues neuronal death. Surprisingly, only the longest Bchs isoform colocalizes well with autophagosomes, and shuttles between different vesicular locations depending on the type of autophagic impetus applied. Our results are consistent with Bchs promoting autophagic maturation, and the BEACH domain being required for this function.HIGHLIGHTSThe autophagic adaptor blue cheese is placed in an epistatic hierarchy, using pharmacological and genetic modulation of bchs- motor neuron degeneration. An intact BEACH isoform can promote autophagic proliferation, and in primary larval brain neurons Bchs shuttles to different components of the autophagy machinery, dependent on the stimulus.

The occurrence and dietary exposure assessment of 16 mycotoxins, 6 biogenic amines (BAs), and 13 metallic elements in blue-veined cheeses (n = 46) is reported. Co-occurrence of mycophenolic acid (≤599 µg·kg−1) with roquefortine C (≤5454 µg·kg−1) was observed in 63% of the tested cheeses, while BAs were frequently present at concentrations between 0.2 and 717 mg kg−1. The concentrations of heavy metals in cheeses were very low. Chronic/acute exposure assessment based on consumption data from different European populations indicated that the levels of mycotoxins and heavy metals are safe to consumers, whereas, rather high hazard indexes (HI up to 0.77) were determined for BAs according to the worst-case scenario based on high consumption and 95th percentile occurrence. A more detailed acute dietary intake study indicated that histamine and tyramine were predominant among these BAs, reaching 27 and 41% of the acute oral intake reference doses.

Abstract: Blue cheese is commonly aged for 60 days at 10°C after curing. However, some manufacturers store blue cheese at 4°C and the effect of lower storage temperature on blue cheese final properties is unknown. Thus, the objective of this study was to determine the effect of storage temperature and time on blue cheese mechanical behaviors. Blue cheeses were stored at 4 or 10°C for 77 days after production. Composition and small‐ and large‐strain rheological behaviors were evaluated every 2 weeks of storage. Storage time had significant impact on blue cheese rheological behaviors; storage temperature did not. Large‐strain compressive force and viscoelastic moduli decreased with storage time, and the extent of nonlinear viscoelastic behavior increased. These results indicated that sample microstructure likely weakened and was more easily deformed as storage time increased. Overall, blue cheese can be stored at 4–10°C without significant changes to its composition or mechanical behavior. Practical applications: The results of this work can be used by blue cheese manufacturers to better understand the impact of storage time and temperature on blue cheese end quality. Manufacturers can take advantage of the effects of storage time on blue cheese mechanical behaviors to determine how long to age blue cheese to achieve the desired texture. [ABSTRACT FROM AUTHOR]

Ripening of blue-veined cheeses, such as the French Bleu and Roquefort, the Italian Gorgonzola, the English Stilton, the Danish Danablu or the Spanish Cabrales, Picón Bejes-Tresviso, and Valdeón, requires the growth and enzymatic activity of the mold Penicillium roqueforti, which is responsible for the characteristic texture, blue-green spots, and aroma of these types of cheeses. This filamentous fungus is able to synthesize different secondary metabolites, including andrastins, mycophenolic acid, and several mycotoxins, such as roquefortines C and D, PR-toxin and eremofortins, isofumigaclavines A and B, and festuclavine. This review provides a detailed description of the main secondary metabolites produced by P. roqueforti in blue cheese, giving a special emphasis to roquefortine, PR-toxin and mycophenolic acid, and their biosynthetic gene clusters and pathways. The knowledge of these clusters and secondary metabolism pathways, together with the ability of P. roqueforti to produce beneficial secondary metabolites, is of interest for commercial purposes. [ABSTRACT FROM AUTHOR]

In the annual reports of the European Food Safety Authority (EFSA), Yersinia enterocolitica (YE) is enumerated as the third most common enteric pathogen responsible for food poisonings. The objective of the paper was to determine the potential for Yersinia enterocolitica growth in blue cheese and in blue cheese with a probiotic ( Lactobacillus acidophilus LA-5®) . The experiment was carried out with five different cheese batches. The potential of YE growth was determined at 3, 6, 9, 12 and 15 °C in ten time intervals up to 480 h of storage. The initial contamination level was set at ~10 cfu/g YE. The studies demonstrated that at lower temperatures there was a systematic increase in the number of cells throughout the storage period, whereas at higher temperatures stationary and die-off phases were observed. By comparing the increase in the number of YE cells in both cheese varieties, it may be observed that at 6, 9 and 12 °C the number of YE cells was lower in blue cheese with probiotic than in blue cheese at each stage of the experiment although it did not guarantee the microbiological safety of the product. [ABSTRACT FROM AUTHOR]

Brevibacterium linens is an important species in dairy products rendering a specific taste and aroma to numerous smear ripened and blue veined cheeses due to proteolysis. However, the presence of the species in South African blue veined cheeses is undesirable and consumers demand the product void of the species. Accordingly, numerous methods including microbial inhibition using fungi and bacterial probiotic cultures with possible inhibitory effects were applied in an attempt to inhibit the species. None of the fungi, however, proved to be successful, whereas Lactobacillus rhamnosus and Bifidobacterium lactis, two typical probiotic species applied in dairy products, showed inhibitory effects against B. linens when tested using the spot-on-lawn assay.

Varieties of blue veined cheese were analyzed regularly during different stages of manufacturing and ripening to determine the origin of contaminating the yeasts present in them, their population diversity and development until the end of the storage. Yeast diversity and development in the inner and outer core of the cheeses during ripening were also compared. Air samples revealed few if any yeasts whereas the samples in contact with the equipment and the surroundings revealed high number of yeasts, implicating it as the possible main source of post-pasteurization contamination, as very few yeasts were isolated from the milk and cheese making process itself. Samples from the inner and outer core of the maturing cheeses had typical survival curves. The number of yeasts on the outer core was about a 100-fold more than of those in the inner core. The most abundant yeasts isolated from the environment and ripening cheeses were identified as Debaryomyces hansenii, Saccharomyces cerevisiae, Torulaspora delbrueckii, Trichosporon beigelii, Candida versatilis and Cryptococcus albidus, while the yeasts Candida zeylanoides and Dekkera anomala were additionally isolated from the environment. Yeasts were present in high number, making their occurrence in blue-veined cheeses meaningful.

This paper examines the impact of Geographical Indications in cheese mountain areas, exploring their potential to contribute to landscape and environmental sustainability by drawing on field work and documental evidences from Cabrales (Asturias, NW Spain). The Cabrales mountain, nestled in the Picos de Europa National Park, embraces a millenary culture linked to the elaboration of an intense flavor blue cheese. The commercial success of this cheese motivated, 40 years ago, the creation of the Cabrales Protected Designation of Origin (PDO). From that moment on, the implementation of certain control measures that affect the production process, together with the increase in demand, led to the disappearance of small producers and to the intensification of livestock management practices. Cheese producers took the opportunity that the PDO label gave them, and the PDO provided the context in which cheese production became an effective barrier against the degradation of the rural system. However, nowadays the intensification of livestock management practices constitutes the main threat to landscape and environmental conservation. Therefore, Local administrators and stakeholders should consider the need to reinforce the idea of a product whose quality is linked to environmental and landscape sustainability through the maintenance of the traditional extensive management practices. • Cabrales cheese production acts as a barrier against the demotion of the rural system. • Increased demand caused the emergence of differences in cheese production. • Extensive production is linked to a superior cheese that increases brand prestige. • Intensification of livestock management practices hinders landscape conservation. [ABSTRACT FROM AUTHOR]

A new chromogenic array for the identification and classification of blue cheeses has been developed. It is based on the response of a chromogenic array composed of five sensing materials prepared by the incorporation of pH indicators to MCM-41 and alumina. Four blue cheeses were tested: Roquefort, Blue Stilton, blue cheese with leaves and blue cheese spread. The colour modulations of the chromogenic array were processed by the principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). The statistical PCA analysis showed different responses to each cheese. PLS-DA models were developed by incorporating the data measured at diverse times, and this approach allowed us to obtain a perfect classification of all five cheeses in 5.5 h. The results suggest that chromogenic arrays and optoelectronic noses can be a suitable approach to develop simple systems to classify blue cheeses and of potential use for the detection of food fraud. [ABSTRACT FROM AUTHOR]