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Microbiology Insights 2022Mycotoxin contamination is a major food safety drawback towards the commercialization of food products. The commercialization of , a popular fermented alcoholic beverage...
Mycotoxin contamination is a major food safety drawback towards the commercialization of food products. The commercialization of , a popular fermented alcoholic beverage of Botswana necessitates the investigation of the presence of mycotoxins. brewing involves the uncontrolled and unstandardized spontaneous fermentation of sun-dried fruits, which could be a source of mycotoxin-producing filamentous fungi (molds). This study sought to investigate the presence of mycotoxins producing fungi and mycotoxins in 18 samples of collected in Central and Northern Botswana. longiciliata, and were identified in 10 out of 18 samples. Mycotoxins were detected using the Myco-10 Randox Evidence Investigator biochip kit and confirmed using a UPLC-ESI-MS/MS. Mycotoxins such as paxilline, ochratoxin A, ergot alkaloids, aflatoxin G1/G2, and zearalenone were detected using the Myco-10 Randox Evidence Investigator biochip kit. The Myco-10 results revealed that the mycotoxins in the samples were lower than the regulatory limits set by FDA or European Commission. Confirmation of results using an UPLC-ESI-MS/MS system involved confirming selected mycotoxins (AFB1, DON. ZEA, FB1, FB2, FB3, NIV, and OTA) from selected samples (Palapye 1, Palapye 2, Letlhakane 2, Maun 3, Mmashoro 3, and Tonota 3). The UPLC results demonstrated that the aforementioned mycotoxins in the selected samples were below the detection thresholds. The study shows that while fungal isolates were present, there is no to minimal danger/risk of exposure to toxic mycotoxins after consumption of . Towards commercialization endeavors, the production process would necessitate minimal mycotoxin monitoring and product preservation but no detoxifying steps.
PubMed: 36452277
DOI: 10.1177/11786361221139817 -
Journal of Applied Microbiology Jan 1998This study compared the effect of temperature (5-45 degrees C), water availability (water activity, aw; 0.995-0.75) and their interactions on the temporal rates of...
This study compared the effect of temperature (5-45 degrees C), water availability (water activity, aw; 0.995-0.75) and their interactions on the temporal rates of germination and mycelial growth of three mycotoxigenic strains of Aspergillus ochraceus and one isolate each of A. flavus, A. niger, Penicillium aurantiogriseum and P. hordei in vitro on a maize extract medium. Germination was very rapid at > 0.90 aw with an almost linear increase with time for all species. However, at < 0.90 aw, the germination rates of A. flavus and P. hordei were slower. The aw minima for germination were usually lower than for growth and varied with temperature. The effect of aw x temperature interactions on the lag phases (h), prior to germination, and on the germination rates (h(-1)), were predicted for the first time for these fungi using the Gompertz model modified by Zwietering. This showed that A. flavus, A. niger and the two Penicillium spp. had very short lag times between 0.995-0.95 aw over a wide temperature range. At marginal temperatures, these were significantly higher, especially at < 10 degrees C for Aspergillus spp. and > 30 degrees C for Penicillium spp. There were also statistically significant differences between lag phases and germination rates for three different isolates of A. ochraceus. The Aspergillus spp. also germinated faster than the Penicillium spp. The temperature x aw profiles for mycelial growth varied considerably between species, both in terms of rates (mm d(-1)) and tolerances. Predictions of the effects of important environmental factors such as temperature, aw and their interactions on lag times to germination, germination rates and mycelial growth are important in the development of hurdle technology approaches to predicting fungal spoilage in agricultural and food products.
Topics: Aspergillus; Environment; Food Microbiology; Penicillium; Temperature; Water; Zea mays
PubMed: 15244054
DOI: 10.1046/j.1365-2672.1997.00297.x -
Foods (Basel, Switzerland) Sep 2023As they continuously evolve, plants will remain a renewable source for antimicrobial compounds. Omani frankincense is produced by trees and is graded into Hojari,...
As they continuously evolve, plants will remain a renewable source for antimicrobial compounds. Omani frankincense is produced by trees and is graded into Hojari, Nejdi, Shazri or Sha'bi. Air can be a source for pathogenic or food spoilage microbes; thus, inactivating airborne microbes is necessary in environments such as food and animal production areas. This study investigated the antimicrobial activity and the chemistry of steam-distilled oils of Hojari and Sha'bi grades. It also analyzed the antimicrobial activity of frankincense smoke and the size of its solid particles. Chemical analysis was performed using gas chromatography mass spectrometry (GC-MS). The antimicrobial activity of the oils against (NCTC 6571), spp., (NCTC 10418), (NCTC 10662), , , , , , , and was determined using well diffusion and micro-well dilution methods. A microscopic technique was used to determine the size of frankincense smoke solid particles. Microbes were exposed to frankincense smoke to test their susceptibility to the smoke. Hojari and Sha'bi oils were similar in composition and contained monoterpenes and sesquiterpenes. The Hojari and the Sha'bi oils possessed broad spectrum antimicrobial activity. The largest growth inhibition zones were obtained with and . An MIC of 1.56% (/) was found with , and . Frankincense smoke contained fine irregular solid particles with a diameter range of 0.8-2287.4 µm, and thus may pose a health risk to susceptible individuals. The smoke had potent antimicrobial activity against , , and airborne bacteria, yeast and mold, with a maximum inhibition of 100%. It was concluded that Hojari and Sha'bi frankincense oils and smoke had significant antimicrobial activity that can be exploited in controlling human, animal and plant pathogenic microbes.
PubMed: 37761150
DOI: 10.3390/foods12183442 -
Nucleic Acids Research Jun 2019SELEX is the cornerstone for aptamer research with broad applications in biosensors and medicine. To improve the affinity of selected aptamers, we propose a...
SELEX is the cornerstone for aptamer research with broad applications in biosensors and medicine. To improve the affinity of selected aptamers, we propose a structure-guided post-SELEX approach, an optimization method based on the precise secondary structure of the aptamer-ligand complex. We demonstrate this approach using the Ochratoxin A (OTA) aptamer. Guided by the structure, we designed a new aptamer whose affinity is improved by more than 50-fold. We also determined the high-resolution NMR structure of the new aptamer-OTA complex and elucidated the discriminatory recognition mechanism of one atomic difference between two analogs, OTA and OTB. The aptamer forms an unusual hairpin structure containing an intramolecular triple helix, which is not seen in the previously determined aptamer complex. The π-π stacking, the hydrophobic interaction, hydrogen bonds and halogen bonds between OTA and the aptamer contribute to the recognition of OTA, and the halogen bonds play an important role in discriminating between OTA and OTB. Our results demonstrate that the structure-guided post-SELEX approach improves aptamers affinity. An improved OTA biosensor system might be developed using this new strategy.
Topics: Aptamers, Nucleotide; Aspergillus ochraceus; Biosensing Techniques; Chlorine; DNA, Single-Stranded; Halogens; Hydrogen Bonding; Ligands; Limit of Detection; Magnetic Resonance Spectroscopy; Molecular Conformation; Ochratoxins; Penicillium; Protein Conformation; Protein Structure, Secondary; SELEX Aptamer Technique
PubMed: 31062016
DOI: 10.1093/nar/gkz336 -
PloS One 2013The presence of fungi on liquorice could contaminate the crop and result in elevated levels of mycotoxin. In this study, the mycobiota associated with fresh and dry...
The presence of fungi on liquorice could contaminate the crop and result in elevated levels of mycotoxin. In this study, the mycobiota associated with fresh and dry liquorice was investigated in 3 producing regions of China. Potential toxigenic fungi were tested for ochratoxin A (OTA) and aflatoxin B1 (AFB1) production using liquid chromatography/mass spectrometry/mass spectrometry. Based on a polyphasic approach using morphological characters, β-tubulin and RNA polymerase II second largest subunit gene phylogeny, a total of 9 genera consisting of 22 fungal species were identified, including two new Penicillium species (Penicillium glycyrrhizacola sp. nov. and Penicillium xingjiangense sp. nov.). The similarity of fungal communities associated with fresh and dry liquorice was low. Nineteen species belonging to 8 genera were detected from fresh liquorice with populations affiliated with P. glycyrrhizacola, P. chrysogenum and Aspergillus insuetus comprising the majority (78.74%, 33.33% and 47.06% of total) of the community from Gansu, Ningxia and Xinjiang samples, respectively. In contrast, ten species belonging to 4 genera were detected from dry liquorice with populations affiliated with P. chrysogenum, P. crustosum and Aspergillus terreus comprising the majority (64.00%, 52.38% and 90.91% of total) of the community from Gansu, Ningxia and Xinjiang samples, respectively. Subsequent LC/MS/MS analysis indicated that 5 fungal species were able to synthesize OTA in vitro including P. chrysogenum, P. glycyrrhizacola, P. polonicum, Aspergillus ochraceus and A. westerdijkiae, the OTA concentration varied from 12.99 to 39.03 µg/kg. AFB1 was absent in all tested strains. These results demonstrate the presence of OTA producing fungi on fresh liquorice and suggest that these fungi could survive on dry liquorice after traditional sun drying. Penicillium chrysogenum derived from surrounding environments is likely to be a stable contributor to high OTA level in liquorice. The harvesting and processing procedure needs to be monitored in order to keep liquorice free of toxigenic fungi.
Topics: Aflatoxin B1; China; Chromatography, Liquid; Food Contamination; Fungi; Glycyrrhiza; Mycotoxins; Ochratoxins; Phylogeny; RNA Polymerase II; Tandem Mass Spectrometry; Tubulin
PubMed: 24205182
DOI: 10.1371/journal.pone.0078285 -
BMC Veterinary Research Oct 2022This study aimed to evaluate the ameliorative effects of dietary supplementation of local bentonite clay (BN) and distillery sludge (DS) alone and in combination on...
BACKGROUND
This study aimed to evaluate the ameliorative effects of dietary supplementation of local bentonite clay (BN) and distillery sludge (DS) alone and in combination on ochratoxin-A (OTA) induced toxicity in broilers. For this purpose, day-old-broiler chicks (n = 270) were procured from the local market and reared under standard management conditions. After 7 days of acclimatization, birds were divided into 2 main groups A and B with respect to OTA inclusion level in feed, each with four sub-groups viz. A1-A4, each challenged with OTA at a dietary inclusion level of 250 µg/kg feed and B1-B4, each challenged with OTA at the level of 500 µg/kg feed and a common control group that was fed with basal feed throughout the experiment. In groups A and B, BN and DS were administered with feed at the rate of 10 g/kg of feed and 5 g/kg of feed alone and in combination, respectively.
RESULTS
Results showed that OTA administration alone resulted in poor feed conversion ratio (FCR) and immunological responses along with increased serum levels of alanine transaminase (ALT), Aspartate transaminase (AST), urea and creatinine (P < 0.05). A significant decrease (P < 0.05) in serum protein levels (albumin, globulin and total protein) was also observed in OTA-fed groups in a dose-dependent manner. The addition of BN at 10 g/kg of OTA-contaminated feed resulted in better FCR and immunological responses as compared to those fed OTA only. The BN supplementation also conferred protection against elevation of serum biochemical parameters when compared with OTA-fed groups. However, the addition of DS could not provide significant protection (P > 0.05) on alteration of serum biochemical parameters in response to the OTA induced toxicity. The combined supplementation of BN and DS resulted in amelioration of OTA-induced toxicity and showed improved FCR, immunological, hematological and serum biochemical parameters (P < 0.05) when compared with other groups. Similarly, BN and DS resulted in a significant decline (P < 0.05) in the OTA tissue residues compared with other groups and control.
CONCLUSION
In conclusion, combined dietary supplementation of BN (10 mg/kg) and DS (05 mg/kg) in feed reduced the toxic effects of OTA contamination at levels of 250 and 500 µg/kg of feed in broilers. So, the combination products of BN and DS may be successfully developed for use in poultry for protection against OTA-induced toxicity in broilers.
Topics: Animals; Ochratoxins; Chickens; Bentonite; Clay; Sewage; Animal Feed; Alanine Transaminase; Creatinine; Diet; Dietary Supplements; Aspartate Aminotransferases; Urea; Albumins
PubMed: 36261856
DOI: 10.1186/s12917-022-03466-3 -
Journal of Food Protection May 1980Eighteen strains of Aspergillus flavus or Aspergillus parasiticus , one of Aspergillus ochraceus and 12 strains or species of Penicillium , many of them isolated from...
Eighteen strains of Aspergillus flavus or Aspergillus parasiticus , one of Aspergillus ochraceus and 12 strains or species of Penicillium , many of them isolated from cheese, were evaluated for their proteolytic and lipolytic activities. Strains of A. flavus exhibited considerable proteolytic and little lipolytic activity, whereas the reverse was true for strains of A. parasiticus . Of the Penicillium cultures tested, 10 exhibited considerable lipolytic activity, but only five had marked proteolytic activity. Two cultures, Penicillium patulum M59, and Penicillium cyclopium No. 8, were markedly lipolytic and proteolytic. Of the other cultures, greatest lipolytic activity was associated with Penicillium roqueforti 849, Penicillium puberulum No. 33, A. parasiticus NRRL 3145 and NRRL 465 and A. ochraceus NRRL 3174, whereas greatest proteolytic activity of all the cultures was associated with P. patulum M59, P. cyclopium No. 25 and A. flavus WB500, 4018, 4098 and NRRL 5565.
PubMed: 30822878
DOI: 10.4315/0362-028X-43.5.354 -
Journal of Food Protection Feb 1985Effects of potassium sorbate on growth and ochratoxin production by Aspergillus ochraceus NRRL 3174 and Penicillium sp. isolated from cheese were studied. Potassium...
Effects of potassium sorbate on growth and ochratoxin production by Aspergillus ochraceus NRRL 3174 and Penicillium sp. isolated from cheese were studied. Potassium sorbate at 0.05, 0.10 and 0.15% delayed or prevented spore germination and initiation of growth, and decreased the rate of growth of both organisms in yeast-extract sucrose (YES) broth at 12°C. However, at 25°C germination and growth of A. ochraceus was more rapid. Increasing concentrations of sorbate caused more variation in the amount of total mycelial growth of Penicillium sp. and generally resulted in a decrease in total mycelial mass. Potassium sorbate also greatly reduced or prevented production of ochratoxin by Penicillium sp. for up to 70 d at 12°C. At 0.05 and 0.10% sorbate, ochratoxin production was greatly reduced over the control, and was eliminated at 0.15%. Overall, ochratoxin production by Penicillium sp. in the presence of sorbate was very low or eliminated. On the other hand, A. ochraceus responded somewhat differently to sorbate. At 12°C, A. ochraceus was similarly inhibited by all three levels of sorbate, and did not produce ochratoxin. When incubated at 25°C, A. ochraceus grew quite readily and appeared to produce greater amounts of ochratoxin in the presence of sorbate, especially at the 0.05% level. Considerably higher levels of ochratoxin were produced at 0.05% sorbate than the control, and somewhat higher levels were obtained at 0.10 and 0.15% sorbate.
PubMed: 30934526
DOI: 10.4315/0362-028X-48.2.162 -
Journal of Clinical Microbiology Mar 2017A multilocus phylogenetic study was carried out to assess species identity of a set of 34 clinical isolates from section from the United States and to determine their...
A multilocus phylogenetic study was carried out to assess species identity of a set of 34 clinical isolates from section from the United States and to determine their antifungal susceptibility against eight antifungal drugs. The genetic markers used were the internal transcribed spacer (ITS) region, and fragments of the beta-tubulin (), calmodulin (), and RNA polymerase II second largest subunit () genes. The drugs tested were amphotericin B, itraconazole, posaconazole, voriconazole, anidulafungin, caspofungin, micafungin, and terbinafine. The most common species sampled was (29.4%), followed by a novel species, which was described here as (23.5%). Other species identified were (17.6%), (8.8%), (8.8%), and and , with two isolates (5.9%) of each. The drugs that showed the most potent activity were caspofungin, micafungin, and terbinafine, while amphotericin B showed the least activity.
Topics: Antifungal Agents; Aspergillosis; Aspergillus; Calmodulin; Cluster Analysis; DNA, Fungal; DNA, Ribosomal Spacer; Humans; Microbial Sensitivity Tests; Phylogeny; RNA Polymerase II; Sequence Analysis, DNA; Tubulin; United States
PubMed: 28053212
DOI: 10.1128/JCM.02012-16 -
Applied Microbiology Apr 1970Five isolates of Aspergillus ochraceus, obtained from peanuts, were grown separately on sterile, moist corn for 14 days and fed to 1-day-old Babcock B-300 cockerels to...
Five isolates of Aspergillus ochraceus, obtained from peanuts, were grown separately on sterile, moist corn for 14 days and fed to 1-day-old Babcock B-300 cockerels to evaluate their toxic effects. Two isolates were highly toxic, causing death of all birds during the 1st week of the experiment. Two isolates were moderately toxic, causing severe growth suppression with some deaths occurring throughout the 3-week test period. One isolate had no apparent effect. When the two most toxic isolates (diets) were diluted, survival time increased but severe growth suppression was evident. Postmortem examinations revealed a few small hemorrhages in the proventriculi of birds which died between the 2nd and 5th days. Emaciation, dehydration, and dry, firm gizzard linings were observed throughout the experiment. Extensive hepatic injury consisting of either fatty changes or necrotic foci was the principal microscopic finding. Suppression of bone marrow activity and depletion of lymphoid elements in the spleen and bursa of Fabricius were also found. The severity of the histopathological changes was directly related to the concentration of ochratoxin A in the diets.
Topics: Animals; Arachis; Aspergillus; Body Weight; Bone Marrow; Bursa of Fabricius; Chickens; Culture Media; Gizzard, Avian; Liver; Male; Mycotoxins; Poisoning; Spleen; Zea mays
PubMed: 5418941
DOI: 10.1128/am.19.4.594-597.1970