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Toxins
Special Issues
New Insights of Ochratoxins
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New Insights of Ochratoxins

A special issue of Toxins (ISSN 2072-6651). This special issue belongs to the section "Mycotoxins".

Deadline for manuscript submissions: closed (31 October 2021) | Viewed by 10695

Special Issue Editor

Dr. Hyun Jung Lee

E-Mail Website
Guest Editor
University of Idaho, School of Food Science, Moscow, United States
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Ochratoxin A (OTA) has received attention in recent years as one of the most commonly occurring mycotoxins in the world. OTA is known as nephrotoxin and a possible human carcinogen. This mycotoxin is produced by many Aspergillus and Penicillium species that commonly occur in foods. Because of the diverse environmental conditions in which those fungi can grow and owing to the heat stability under most food processing conditions, OTA has been found in a wide range of agricultural commodities and their derived food products, especially in oats and oat-based products. The toxicity mechanism of OTA is still unclear, but it is absorbed into the gastrointestinal tract through food intake, and then absorbed OTA binds to albumin which has a very long half-life, resulting in its accumulation. Therefore, contamination of OTA in foods is a significant concern in food safety and public health. This Special Issue is dedicated to current understanding of the impact of OTA on human health, including its mechanism and toxicology, risk assessment, processing technologies and surveillance, as well as mycology or fungal biology. Review articles on this topic will also be considered.

Dr. Hyun Jung Lee
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a double-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Toxins is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Ochratoxin A (OTA)
  • food safety
  • public health
  • occurrence
  • exposure
  • toxicity
  • mechanism
  • determination
  • risk assessment

Published Papers (4 papers)

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Research

15 pages, 2401 KiB  
Article
Human Proximal Tubule Epithelial Cells (HK-2) as a Sensitive In Vitro System for Ochratoxin A Induced Oxidative Stress
by Enrique García-Pérez, Dojin Ryu, Hwa-Young Kim, Hae Dun Kim and Hyun Jung Lee
Toxins 2021, 13(11), 787; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13110787 - 06 Nov 2021
Cited by 8 | Viewed by 2495
Abstract
Ochratoxin A (OTA) is a mycotoxin that is potentially carcinogenic to humans. Although its mechanism remains unclear, oxidative stress has been recognized as a plausible cause for the potent renal carcinogenicity observed in experimental animals. The effect of OTA on oxidative stress parameters [...] Read more.
Ochratoxin A (OTA) is a mycotoxin that is potentially carcinogenic to humans. Although its mechanism remains unclear, oxidative stress has been recognized as a plausible cause for the potent renal carcinogenicity observed in experimental animals. The effect of OTA on oxidative stress parameters in two cell lines of LLC-PK1 and HK-2 derived from the kidneys of pig and human, respectively, were investigated and compared. We found that the cytotoxicity of OTA on LLC-PK1 and HK-2 cells was dose- and time-dependent in both cell lines. Furthermore, increased intracellular reactive oxygen species (ROS) induced by OTA in both cell lines were observed in a time-dependent manner. Glutathione (GSH) was depleted by OTA at >48 h in HK-2 but not in LLC-PK1 cells. While the mRNA levels of glucose-6-phosphate dehydrogenase (G6PD) and glutathione peroxidase 1 (GPX1) in LLC-PK1 were down-regulated by 0.67- and 0.66-fold, respectively, those of catalase (CAT), glutathione reductase (GSR), and superoxide dismutase 1 (SOD) in HK-2 were up-regulated by 2.20-, 2.24-, and 2.75-fold, respectively, after 72 h exposure to OTA. Based on these results, we conclude that HK-2 cells are more sensitive to OTA-mediated toxicity than LLC-PK1, and OTA can cause a significant oxidative stress in HK-2 as indicated by changes in the parameter evaluated. Full article
(This article belongs to the Special Issue New Insights of Ochratoxins)
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11 pages, 2438 KiB  
Article
Comparison of Flow Injection-MS/MS and LC-MS/MS for the Determination of Ochratoxin A
by Kai Zhang
Toxins 2021, 13(8), 547; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13080547 - 06 Aug 2021
Cited by 3 | Viewed by 2401
Abstract
Two methods for measuring ochratoxin A in corn, oat, and grape juice were developed and compared. Flow injection (FI) and on-line liquid chromatography (LC) performances were evaluated separately, with both methods using a triple quadrupole tandem mass spectrometer (MS/MS) for quantitation. Samples were [...] Read more.
Two methods for measuring ochratoxin A in corn, oat, and grape juice were developed and compared. Flow injection (FI) and on-line liquid chromatography (LC) performances were evaluated separately, with both methods using a triple quadrupole tandem mass spectrometer (MS/MS) for quantitation. Samples were fortified with 13C uniformly labeled ochratoxin A as the internal standard (13C-IS) and prepared by dilution and filtration, followed by FI- and LC-MS/MS analysis. For the LC-MS/MS method, which had a 10 min run time/sample, recoveries of ochratoxin A fortified at 1, 5, 20, and 100 ppb in corn, oat, red grape juice, and white grape juice ranged from 100% to 117% with RSDs < 9%. The analysis time of the FI-MS/MS method was <60 s/sample, however, the method could not detect ochratoxin A at the lowest fortification concentration, 1 ppb, in all tested matrix sources. At 5, 20, and 100 ppb, recoveries by FI-MS/MS ranged from 79 to 117% with RSDs < 15%. The FI-MS/MS method also had ~5× higher solvent and matrix-dependent instrument detection limits (0.12–0.35 ppb) compared to the LC-MS/MS method (0.02–0.06 ppb). In the analysis of incurred corn and oat samples, both methods generated comparable results within ±20% of reference values, however, the FI-MS/MS method failed to determine ochratoxin A in two incurred wheat flour samples due to co-eluted interferences due to the lack of chromatographic separation. Full article
(This article belongs to the Special Issue New Insights of Ochratoxins)
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12 pages, 2657 KiB  
Article
Ochratoxin A Induces Oxidative Stress in HepG2 Cells by Impairing the Gene Expression of Antioxidant Enzymes
by Enrique García-Pérez, Dojin Ryu, Chan Lee and Hyun Jung Lee
Toxins 2021, 13(4), 271; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13040271 - 09 Apr 2021
Cited by 19 | Viewed by 2730
Abstract
Ochratoxin A (OTA) is a mycotoxin frequently found in raw and processed foods. While it is considered a possible human carcinogen, the mechanism of action remains unclear. OTA has been shown to be hepatotoxic in both in vitro and in vivo models and [...] Read more.
Ochratoxin A (OTA) is a mycotoxin frequently found in raw and processed foods. While it is considered a possible human carcinogen, the mechanism of action remains unclear. OTA has been shown to be hepatotoxic in both in vitro and in vivo models and oxidative stress may be one of the factors contributing to its toxicity. Hence, the effect of OTA on human hepatocellular carcinoma, HepG2 cells, was investigated on oxidative stress parameters. The cytotoxicity of OTA on HepG2 was time- and dose-dependent within a range between 0.1 and 10 µM; while 100 μM of OTA increased the intracellular reactive oxygen species (ROS) in a time-dependent manner. Additionally, the levels of glutathione (GSH) were increased by 9.7% and 11.3% at 10 and 100 nM of OTA, respectively; while OTA at 100 μM depleted GSH by 40.5% after 24 h exposure compared with the control. Finally, the mRNA level of catalase (CAT) was downregulated by 2.33-, 1.92-, and 1.82-fold after cells were treated with 1, 10, and 10 μM OTA for 24 h, respectively; which was linked to a decrease in CAT enzymatic activity. These results suggest that oxidative stress is involved in OTA-mediated toxicity in HepG2 cells. Full article
(This article belongs to the Special Issue New Insights of Ochratoxins)
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8 pages, 305 KiB  
Article
Reduction of Ochratoxin A during the Preparation of Porridge with Sodium Bicarbonate and Fructose
by Hyun Jung Lee, Shufang Li, Kejia Gu and Dojin Ryu
Toxins 2021, 13(3), 224; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13030224 - 19 Mar 2021
Cited by 2 | Viewed by 2397
Abstract
Ochratoxin A (OTA) is a potential human carcinogen that poses a significant concern in food safety and public health. OTA has been found in a wide variety of agricultural commodities, including cereal grains. This study investigated the reduction of OTA during the preparation [...] Read more.
Ochratoxin A (OTA) is a potential human carcinogen that poses a significant concern in food safety and public health. OTA has been found in a wide variety of agricultural commodities, including cereal grains. This study investigated the reduction of OTA during the preparation of rice- and oat-based porridge by a simulated indirect steam process. The effects of sodium bicarbonate (NaHCO3) and fructose on the reduction of OTA were also investigated. During the processing, OTA in rice- and oat-porridge was decreased by 59% and 14%, respectively, from initial OTA artificially added at 20 μg/kg (dry weight basis). When 0.5% and 1% of sodium bicarbonate were added to rice porridge, increased reduction of OTA was observed as 78% and 68%, respectively. The same amounts of added sodium bicarbonate also further reduced OTA in oat porridge to 58% and 72%, respectively. In addition, increased reduction of OTA in the presence of fructose was observed. A combination of the two, i.e., 0.5% sodium bicarbonate and 0.5% fructose, resulted in a 79% and 67% reduction in rice porridge and oat porridge, respectively. These results indicate that indirect steaming may effectively reduce OTA in preparation of porridge-type products, particularly when sodium bicarbonate and/or fructose are added. Full article
(This article belongs to the Special Issue New Insights of Ochratoxins)
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