This page has only limited features, please log in for full access.

Unclaimed
Dojin Ryu
Department of Animal, Veterinary, and Food Sciences, University of Idaho, 875 Perimeter Drive MS 2330, Moscow, ID 83844-2330, USA

Honors and Awards

The user has no records in this section


Career Timeline

The user has no records in this section.


Short Biography

The user biography is not available.
Following
Followers
Co Authors
The list of users this user is following is empty.
Following: 0 users

Feed

Journal article
Published: 09 April 2021 in Toxins
Reads 0
Downloads 0

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.

ACS Style

Enrique García-Pérez; Dojin Ryu; Chan Lee; Hyun Lee. Ochratoxin A Induces Oxidative Stress in HepG2 Cells by Impairing the Gene Expression of Antioxidant Enzymes. Toxins 2021, 13, 271 .

AMA Style

Enrique García-Pérez, Dojin Ryu, Chan Lee, Hyun Lee. Ochratoxin A Induces Oxidative Stress in HepG2 Cells by Impairing the Gene Expression of Antioxidant Enzymes. Toxins. 2021; 13 (4):271.

Chicago/Turabian Style

Enrique García-Pérez; Dojin Ryu; Chan Lee; Hyun Lee. 2021. "Ochratoxin A Induces Oxidative Stress in HepG2 Cells by Impairing the Gene Expression of Antioxidant Enzymes." Toxins 13, no. 4: 271.

Journal article
Published: 19 March 2021 in Toxins
Reads 0
Downloads 0

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.

ACS Style

Hyun Lee; Shufang Li; Kejia Gu; Dojin Ryu. Reduction of Ochratoxin A during the Preparation of Porridge with Sodium Bicarbonate and Fructose. Toxins 2021, 13, 224 .

AMA Style

Hyun Lee, Shufang Li, Kejia Gu, Dojin Ryu. Reduction of Ochratoxin A during the Preparation of Porridge with Sodium Bicarbonate and Fructose. Toxins. 2021; 13 (3):224.

Chicago/Turabian Style

Hyun Lee; Shufang Li; Kejia Gu; Dojin Ryu. 2021. "Reduction of Ochratoxin A during the Preparation of Porridge with Sodium Bicarbonate and Fructose." Toxins 13, no. 3: 224.

Journal article
Published: 03 May 2020 in Food Control
Reads 0
Downloads 0

Ochratoxin A (OTA) is a possible human carcinogen found in a wide range of foods and agricultural commodities worldwide. This potent nephrotoxin is of concern because of its thermal stability under most conditions used during food processing and high incidence and concentration in oat-based baby foods. In this study, the effects of added baking soda (0.5% and 1%; w/w), fructose (0.5% and 5%; w/w), or combination of both (baking soda 0.5% + fructose 0.5%; w/w) on the stability of OTA during retorting of porridge type products made of oat flour or rice flour (10% solid content; w/v) were investigated using a laboratory scale horizontal steam retort. The reduction of OTA after retort was 17.2% in oat porridge and 53.8% in rice porridge, while addition of baking soda resulted in greater reduction of OTA. In retorted oat porridge, reduction of OTA was 30.3% and 47.9% with 0.5% and 1.0% of added baking soda, respectively. The reduction of OTA in retorted rice porridge reached 55.5% and 66.4% with 0.5% and 1% baking soda, respectively. Addition of fructose resulted in greater reduction of OTA in oat porridge (35.5–40.8%) but not in rice porridge. The reduction of OTA in retorted rice and oat porridges with combination 0.5% baking soda and 0.5% fructose were 35.8% and 39.8%, respectively. These results suggest that OTA may be reduced significantly by retorting of oat and rice porridge. In addition, added baking soda may contribute to the reduction of OTA in rice and oat porridges while added fructose may facilitate OTA reduction in oat porridge.

ACS Style

Hyun Jung Lee; Chan Lee; Dojin Ryu. Effects of baking soda and fructose in reduction of ochratoxin A in rice and oat porridge during retorting process. Food Control 2020, 116, 107325 .

AMA Style

Hyun Jung Lee, Chan Lee, Dojin Ryu. Effects of baking soda and fructose in reduction of ochratoxin A in rice and oat porridge during retorting process. Food Control. 2020; 116 ():107325.

Chicago/Turabian Style

Hyun Jung Lee; Chan Lee; Dojin Ryu. 2020. "Effects of baking soda and fructose in reduction of ochratoxin A in rice and oat porridge during retorting process." Food Control 116, no. : 107325.

Journal article
Published: 25 February 2020 in Foods
Reads 0
Downloads 0

An analytical method to measure solubilized orthophosphate ions (HPO42− and PO43− ) from the water-insoluble food additives calcium phosphate dibasic (DCP) and calcium phosphate tribasic (TCP) in processed foods was optimized by comparing ion chromatography (IC) coupled with DS6 conductivity detector (Cond.) and high-performance liquid chromatography (HPLC) with Evaporative light scattering detector (ELSD) methods. The ion-pairing HPLC method could analyze calcium and phosphate ions successively. However, this method exhibited low reproducibility after approximately 48 hours of measurements. The IC method was established as an effective method of measuring orthophosphate ions with high reproducibility using distilled water and KOH solution as the mobile phase with a Dionex column. Matrix-based limit of detections (LOD) and limit of quantifications (LOQ) for snacks and cereals were estimated in the range of 0.01–0.91 µg/mL and 0.21–2.74 µg/mL, respectively. In inter-day and intra-day tests, the calculated precision (%RSD) and accuracy (recovery %) ranged from 0.5% to 6.6% and 82% to 117%, respectively, in both food samples. The levels of DCP or TCP could be analyzed in various positive food samples, and the developed IC method demonstrated good applicability in the analysis of DCP and TCP in collected processed foods.

ACS Style

Minjung Song; Juhee Park; Jihyun Lee; Heejae Suh; Hyunjung Lee; Dojin Ryu; Chan Lee. New Analytical Approach for the Determination of Calcium Phosphate Dibasic and Tribasic in Processed Food by Comparison of Ion Chromatography with High-Performance Liquid Chromatography. Foods 2020, 9, 248 .

AMA Style

Minjung Song, Juhee Park, Jihyun Lee, Heejae Suh, Hyunjung Lee, Dojin Ryu, Chan Lee. New Analytical Approach for the Determination of Calcium Phosphate Dibasic and Tribasic in Processed Food by Comparison of Ion Chromatography with High-Performance Liquid Chromatography. Foods. 2020; 9 (3):248.

Chicago/Turabian Style

Minjung Song; Juhee Park; Jihyun Lee; Heejae Suh; Hyunjung Lee; Dojin Ryu; Chan Lee. 2020. "New Analytical Approach for the Determination of Calcium Phosphate Dibasic and Tribasic in Processed Food by Comparison of Ion Chromatography with High-Performance Liquid Chromatography." Foods 9, no. 3: 248.

Journal article
Published: 29 June 2019 in Toxins
Reads 0
Downloads 0

Ochratoxin A (OTA) is a widespread mycotoxin produced by several species of the genera Aspergillus and Penicillium. OTA exists in a variety of foods, including rice, oats, and coffee and is hepatotoxic, with a similar mode of action as aflatoxin B1. The precise mechanism of cytotoxicity is not yet known, but oxidative damage is suspected to contribute to its cytotoxic effects. In this study, human hepatocyte HepG2 cells were treated with various concentrations of OTA (5–500 nM) for 48 h. OTA triggered oxidative stress as demonstrated by glutathione depletion and increased reactive oxygen species, malondialdehyde level, and nitric oxide production. Apoptosis was observed with 500 nM OTA treatment. OTA increased both the mRNA and protein expression of phase I and II enzymes. The same results were observed in an in vivo study using ICR mice. Furthermore, the relationship between phase I and II enzymes was demonstrated by the knockdown of the aryl hydrocarbon receptor (AhR) and NF-E2-related factor 2 (Nrf2) with siRNA. Taken together, our results show that OTA induces oxidative stress through the phase I reaction regulated by AhR and induces apoptosis, and that the phase II reaction is activated by Nrf2 in the presence of oxidative stress.

ACS Style

Hye Soo Shin; Hyun Jung Lee; Min Cheol Pyo; Dojin Ryu; Kwang-Won Lee. Ochratoxin A-Induced Hepatotoxicity through Phase I and Phase II Reactions Regulated by AhR in Liver Cells. Toxins 2019, 11, 377 .

AMA Style

Hye Soo Shin, Hyun Jung Lee, Min Cheol Pyo, Dojin Ryu, Kwang-Won Lee. Ochratoxin A-Induced Hepatotoxicity through Phase I and Phase II Reactions Regulated by AhR in Liver Cells. Toxins. 2019; 11 (7):377.

Chicago/Turabian Style

Hye Soo Shin; Hyun Jung Lee; Min Cheol Pyo; Dojin Ryu; Kwang-Won Lee. 2019. "Ochratoxin A-Induced Hepatotoxicity through Phase I and Phase II Reactions Regulated by AhR in Liver Cells." Toxins 11, no. 7: 377.

Journal article
Published: 14 May 2019 in Food Control
Reads 0
Downloads 0

Ochratoxin A (OTA) is one of the most important mycotoxins due to its widespread occurrence and toxicity, including nephrotoxicity and potential carcinogenicity to humans. OTA has been detected in a wide range of agricultural commodities and their processed products such as infant cereals and breakfast cereals. Extrusion processing, which is widely used in the manufacture of infant and breakfast cereals, may reduce mycotoxin levels to varying degrees. Hence, the effects of extrusion cooking process on the stability of OTA in spiked (100 μg/kg) oat flakes and rice flour was investigated by using a laboratory-scaled twin-screw extruder. In addition, the effect of twin-screw extrusion and addition of baking soda (0, 0.5, and 1.0% weight of total solids) on the reduction of OTA in oats and rice was investigated. The reductions of OTA in the artificially contaminated oat flakes upon extrusion cooking were in the range of 40–43% whereas the reductions in rice flour ranged from 78 to 82%. The reductions of OTA during extrusion with added baking soda were up to 65% and 72% in oats and rice, respectively. These results suggest that OTA in rice and oats may be reduced significantly by extrusion cooking process, which can be applied to commercial production of infant cereals and breakfast cereals. In addition, baking soda may also help to reduce OTA levels in oats during thermal processing.

ACS Style

Dojin Ryu; Ryan Joseph Kowalski; Girish Ganjyal; Hyun Jung Lee. Reduction of ochratoxin A in oats and rice by twin-screw extrusion processing with baking soda. Food Control 2019, 105, 21 -28.

AMA Style

Dojin Ryu, Ryan Joseph Kowalski, Girish Ganjyal, Hyun Jung Lee. Reduction of ochratoxin A in oats and rice by twin-screw extrusion processing with baking soda. Food Control. 2019; 105 ():21-28.

Chicago/Turabian Style

Dojin Ryu; Ryan Joseph Kowalski; Girish Ganjyal; Hyun Jung Lee. 2019. "Reduction of ochratoxin A in oats and rice by twin-screw extrusion processing with baking soda." Food Control 105, no. : 21-28.

Short communication
Published: 04 October 2018 in Food Control
Reads 0
Downloads 0

Ochratoxin A (OTA) is a possible human carcinogen with its potent nephrotoxicity and has been found in many agricultural commodities particularly in oats and its processed foods including oat-based infant cereals. While OTA is stable under most thermal processing conditions, alkaline pH can increase the reduction of OTA. In this study, the effect of direct steam injection (DSI) process along with the absence and presence baking soda (0.5% and 1% of solid contents) on the reduction of OTA in oat-based infant cereals was investigated. Food-grade oat flour was spiked with OTA (100 μg/kg) and equilibrated overnight followed by preparation of slurry by adding water to reach 5% solid content. Then the slurry was processed by DSI at 85°C and 121°C followed by spray drying at 210ºC. Greater reduction of OTA in DSI processed oat-based infant cereals was observed at higher process temperature to result in 20-28% reduction. In addition, the reduction of OTA increased with increasing amounts of baking soda. These results suggest that OTA may be reduced significantly by DSI process, which can be applied to commercial production of oat-based infant cereals. Baking soda may also help to reduce OTA amount in cereal-based infant cereals during thermal processing.

ACS Style

Hyun Jung Lee; Bon-Jae Gu; Girish Ganjyal; Dojin Ryu. Reduction of ochratoxin A in direct steam injected oat-based infant cereals with baking soda. Food Control 2018, 96, 441 -444.

AMA Style

Hyun Jung Lee, Bon-Jae Gu, Girish Ganjyal, Dojin Ryu. Reduction of ochratoxin A in direct steam injected oat-based infant cereals with baking soda. Food Control. 2018; 96 ():441-444.

Chicago/Turabian Style

Hyun Jung Lee; Bon-Jae Gu; Girish Ganjyal; Dojin Ryu. 2018. "Reduction of ochratoxin A in direct steam injected oat-based infant cereals with baking soda." Food Control 96, no. : 441-444.

Journal article
Published: 03 October 2018 in International Journal of Food Microbiology
Reads 0
Downloads 0

Human noroviruses (NoV) are recognized worldwide as important pathogens and the primary cause of foodborne disease outbreaks from contaminated food in the U.S. They are often transmitted by infected food handlers manipulating foods during preparation, such as fresh fruits and vegetables. This paper provides a study to model the transfer of NoV between food handlers and vegetables during salad preparation in school food services based on direct observation data. Three transfer pathways were modeled by considering different initial contamination sources (environment, handlers and contaminated produce). The probability of infection by NoV was also estimated based on the NoV levels at consumption obtained from each simulated transfer pathway. A scenario analysis ranging a wide concentration from 102 to 107 NoV infective particles was performed to represent different levels of NoV in the initial contamination sources. In addition, a sensitivity analysis was applied to identify the most important model inputs and determine the safest handling practices to be implemented in school food service operations. The pathway describing transfer from contaminated surfaces or handlers to foods indicated that initial levels of ≤104 NoV particles/fomite resulted in 0.2). In the pathway modeling cross contamination from contaminated vegetables to non-contaminated vegetables, all scenarios could led to infected individuals, although number of cases of infection were lower (<1.3%), despite concentration levels were higher. On the contrary, for this pathway, prevalence was 2-fold lower than that observed in the pathways describing transfer from contaminated surfaces and hands. Based on the sensitivity analysis, NoV transfers to fresh produce may be minimized by improving hand washing, and therefore effective training programs need to be carried out specifically addressing hand washing. Moreover, the produce's washing step showed to be an effective control measure, depending on the desinfectant efficacy, by reducing % cases of NoV infection from 6 to 1%. The model in this study might be used, in the future, to evaluate the impact on the risk associated with NoV transmission of specific and effective training programs, aimed at food chain operators.

ACS Style

Fernando Pérez-Rodríguez; Junehee Kwon; Araceli Bolívar; Kevin Sauer; Dojin Ryu; Ewen Todd. Probabilistic risk model of norovirus transmission during handling and preparation of fresh produce in school foodservice operations. International Journal of Food Microbiology 2018, 290, 159 -169.

AMA Style

Fernando Pérez-Rodríguez, Junehee Kwon, Araceli Bolívar, Kevin Sauer, Dojin Ryu, Ewen Todd. Probabilistic risk model of norovirus transmission during handling and preparation of fresh produce in school foodservice operations. International Journal of Food Microbiology. 2018; 290 ():159-169.

Chicago/Turabian Style

Fernando Pérez-Rodríguez; Junehee Kwon; Araceli Bolívar; Kevin Sauer; Dojin Ryu; Ewen Todd. 2018. "Probabilistic risk model of norovirus transmission during handling and preparation of fresh produce in school foodservice operations." International Journal of Food Microbiology 290, no. : 159-169.

Journal article
Published: 03 October 2018 in Food and Chemical Toxicology
Reads 0
Downloads 0

Because ochratoxin A (OTA) is widely found in foods, people are susceptible to OTA exposure. The mechanism leading to renal toxicity induced by OTA remains unclear. The aim of this study was to investigate OTA-induced toxicity in human proximal tubule HK-2 cells. OTA decreased cell viability, and the expression of kidney injury molecule-1 (KIM-1), a kidney damage marker, was increased when HK-2 cells were exposed to OTA. Additionally, OTA treatment of cells increased intracellular reactive oxygen species and malondialdehyde and decreased glutathione levels. OTA-treated cells induced the aryl hydrocarbon receptor (AhR) and pregnane X receptor (PXR) genes followed by induction of the cytochrome P450 1A1 (CYP1A1), CYP1A2, and CYP3A4 genes representing phase I enzyme. The mRNA expression of phase II enzymes such as heme oxygenase-1, nicotinamide adenine dinucleotide phosphate-quinone oxidoreductase 1, and glutamate cysteine ligase catalytic subunit were upregulated by activation of NF-E2-related factor 2 (Nrf2) translocation by treatment with OTA. The response of OTA-orally administered mice also showed marked increases in these enzymes as well as KIM-1. These results indicate that OTA induces phase I and II enzymes through the AhR, PXR, and Nrf2 signaling pathways in HK-2 cells, which may lead to modulation of proximal tubule injury.

ACS Style

Hyun Jung Lee; Min Cheol Pyo; Hye Soo Shin; Dojin Ryu; Kwang-Won Lee. Renal toxicity through AhR, PXR, and Nrf2 signaling pathway activation of ochratoxin A-induced oxidative stress in kidney cells. Food and Chemical Toxicology 2018, 122, 59 -68.

AMA Style

Hyun Jung Lee, Min Cheol Pyo, Hye Soo Shin, Dojin Ryu, Kwang-Won Lee. Renal toxicity through AhR, PXR, and Nrf2 signaling pathway activation of ochratoxin A-induced oxidative stress in kidney cells. Food and Chemical Toxicology. 2018; 122 ():59-68.

Chicago/Turabian Style

Hyun Jung Lee; Min Cheol Pyo; Hye Soo Shin; Dojin Ryu; Kwang-Won Lee. 2018. "Renal toxicity through AhR, PXR, and Nrf2 signaling pathway activation of ochratoxin A-induced oxidative stress in kidney cells." Food and Chemical Toxicology 122, no. : 59-68.

Short communication
Published: 06 August 2018 in Food Control
Reads 0
Downloads 0

Ochratoxin A (OTA) represents one of the most widespread mycotoxins in agricultural commodities in the world and is considered as a possible human carcinogen with its potent nephrotoxicity. Since OTA is stable under most food processing conditions, it has been detected in a variety of cereal grains and their processed products. We investigated the effect of explosive puffing process on the reduction of OTA in rice and oats. Moisture content of rice and oat grains were adjusted to 15% (wet weight basis, wb) and OTA was spiked at 100 μg/kg. Then the grains were processed by explosive puffing at 0.5, 0.7, and 0.9 MPa. The moisture content of puffed rice and oat snacks were in the ranges of 5 – 8% wb and 6 – 10% wb, respectively, and the moisture content in the puffed products were decreased with increasing pressure. In addition, decreased bulk density and increased degree of redness (a) were observed with increased explosive puffing pressure. The reduction of OTA concentration in puffed rice and oats were decreased with increasing explosive puffing pressures in the ranges of 15 – 28% and 38 – 52%, respectively. These results suggest that OTA in rice and oat may be reduced significantly by explosive puffing process, which can be applied to commercial production of cereal-based snack foods.

ACS Style

Hyun Jung Lee; Singeun Kim; Hyung Joo Suh; Dojin Ryu. Effects of explosive puffing process on the reduction of ochratoxin A in rice and oats. Food Control 2018, 95, 334 -338.

AMA Style

Hyun Jung Lee, Singeun Kim, Hyung Joo Suh, Dojin Ryu. Effects of explosive puffing process on the reduction of ochratoxin A in rice and oats. Food Control. 2018; 95 ():334-338.

Chicago/Turabian Style

Hyun Jung Lee; Singeun Kim; Hyung Joo Suh; Dojin Ryu. 2018. "Effects of explosive puffing process on the reduction of ochratoxin A in rice and oats." Food Control 95, no. : 334-338.

Journal article
Published: 30 August 2017 in Journal of Food Protection
Reads 0
Downloads 0

Ochratoxin A (OTA) is one of the most important mycotoxins owing to its widespread occurrence and toxicity, including nephrotoxicity and potential carcinogenicity to humans. OTA has been detected in a wide range of agricultural commodities, including cereal grains and their processed products. In particular, oat-based products show a higher incidence and level of contamination. Extrusion cooking is widely used in the manufacturing of breakfast cereals and snacks and may reduce mycotoxins to varying degrees. Hence, the effects of extrusion cooking on the stability of OTA in spiked (100 μg/kg) oat flake was investigated by using a laboratory-scale twin-screw extruder with a central composite design. Factors examined were moisture content (20, 25, and 30% dry weight basis), temperature (140, 160, and 180°C), screw speed (150, 200, and 250 rpm), and die size (1.5, 2, and 3 mm). Both nonextruded and extruded samples were analyzed for reductions of OTA by high-performance liquid chromatography, coupled with fluorescence detection. The percentage of reductions in OTA in the contaminated oat flakes upon extrusion processing were in the range of 0 to 28%. OTA was partially stable during extrusion, with only screw speed and die size having significant effect on reduction (P < 0.005). The highest reduction of 28% was achieved at 180°C, 20% moisture, 250 rpm screw speed, and a 3-mm die with 193 kJ/kg specific mechanical energy. According to the central composite design analyses, up to 28% of OTA can be reduced by a combination of 162°C, 30% moisture, and 221 rpm, with a 3-mm die.

ACS Style

Hyun Jung Lee; Samjhana Dahal; Enrique Garcia Perez; Ryan Joseph Kowalski; Girish M. Ganjyal; Dojin Ryu. Reduction of Ochratoxin A in Oat Flakes by Twin-Screw Extrusion Processing. Journal of Food Protection 2017, 80, 1628 -1634.

AMA Style

Hyun Jung Lee, Samjhana Dahal, Enrique Garcia Perez, Ryan Joseph Kowalski, Girish M. Ganjyal, Dojin Ryu. Reduction of Ochratoxin A in Oat Flakes by Twin-Screw Extrusion Processing. Journal of Food Protection. 2017; 80 (10):1628-1634.

Chicago/Turabian Style

Hyun Jung Lee; Samjhana Dahal; Enrique Garcia Perez; Ryan Joseph Kowalski; Girish M. Ganjyal; Dojin Ryu. 2017. "Reduction of Ochratoxin A in Oat Flakes by Twin-Screw Extrusion Processing." Journal of Food Protection 80, no. 10: 1628-1634.

Review article
Published: 07 February 2017 in Journal of Agricultural and Food Chemistry
Reads 0
Downloads 0

Fumonisins are mycotoxins found in corn. They are toxic to animals and cause cancer in rodents and neural tube defects in LM/Bc mice. Reducing their concentrations in corn-based foods is therefore desirable. Chemical analysis or in vitro bioassays of food extracts might not detect toxic fumonisin reaction products that are unknown or unextractable from food matrices, thus potentially underestimating in vivo toxicity. The effectiveness of two common cooking methods, extrusion and nixtamalization (alkaline cooking), to reduce the toxicity of fumonisin-contaminated corn grits (extrusion) and whole kernel corn (nixtamalization) was shown by means of rat feeding bioassays using fumonisin-specific kidney effects as indicators of potential toxicity. A third bioassay showed that in contrast to fumonisin B1 (FB1), hydrolyzed fumonisin B1 (HFB1; formed from FB1 during nixtamalization) did not cause neural tube defects in LM/Bc mice. The findings indicate that extrusion and nixtamalization reduce the potential toxicity of FB1-contaminated corn.

ACS Style

Kenneth Voss; Dojin Ryu; Lauren Jackson; Ronald Riley; Janee Gelineau-Van Waes. Reduction of Fumonisin Toxicity by Extrusion and Nixtamalization (Alkaline Cooking). Journal of Agricultural and Food Chemistry 2017, 65, 7088 -7096.

AMA Style

Kenneth Voss, Dojin Ryu, Lauren Jackson, Ronald Riley, Janee Gelineau-Van Waes. Reduction of Fumonisin Toxicity by Extrusion and Nixtamalization (Alkaline Cooking). Journal of Agricultural and Food Chemistry. 2017; 65 (33):7088-7096.

Chicago/Turabian Style

Kenneth Voss; Dojin Ryu; Lauren Jackson; Ronald Riley; Janee Gelineau-Van Waes. 2017. "Reduction of Fumonisin Toxicity by Extrusion and Nixtamalization (Alkaline Cooking)." Journal of Agricultural and Food Chemistry 65, no. 33: 7088-7096.

Journal article
Published: 23 January 2017 in Journal of Food Protection
Reads 0
Downloads 0

Ochratoxin A (OTA) is a possible human carcinogen and occurs frequently in cereal grain, soy, and other agricultural commodities. Infants and young children may be more susceptible to contaminants than adults because of their lower body weight, higher metabolic rate, reduced ability to detoxify food toxicants, and more restricted diet. The purpose of this study was to investigate the occurrence and levels of OTA in infant formula and infant cereal products available in the U.S. market. In the present study, 98 powdered infant formula (milk- and soy-based) samples and 155 infant cereal (barley-, rice-, oat-, wheat-, and mixed grain–based) products were collected from different retail locations in the United States over a 2-year period. OTA levels were determined by liquid chromatography–tandem mass spectrometry. Although OTA was not detected in any of the infant formula samples, 47 (30%) of 155 infant cereals were contaminated with OTA in the range of 0.6 to 22.1 ng/g. At present, there is no regulatory limit for OTA in the United States. However, all of the positive samples were above the maximum level set by the European Commission (0.5 ng/g) for OTA in baby foods. OTA was detected in all types of infant cereals, but the highest incidence and concentrations were found in oat-based infant cereals (59%), followed by mixed grain cereals (34%). Increased surveillance and monitoring of OTA levels in grains used in infant foods may be needed to reduce exposure of infants and young children to OTA from cereal products.

ACS Style

Jack Cappozzo; Lauren Jackson; Hyun Jung Lee; Wei Zhou; Fadwa Al-Taher; Jerry Zweigenbaum; Dojin Ryu. Occurrence of Ochratoxin A in Infant Foods in the United States. Journal of Food Protection 2017, 80, 251 -256.

AMA Style

Jack Cappozzo, Lauren Jackson, Hyun Jung Lee, Wei Zhou, Fadwa Al-Taher, Jerry Zweigenbaum, Dojin Ryu. Occurrence of Ochratoxin A in Infant Foods in the United States. Journal of Food Protection. 2017; 80 (2):251-256.

Chicago/Turabian Style

Jack Cappozzo; Lauren Jackson; Hyun Jung Lee; Wei Zhou; Fadwa Al-Taher; Jerry Zweigenbaum; Dojin Ryu. 2017. "Occurrence of Ochratoxin A in Infant Foods in the United States." Journal of Food Protection 80, no. 2: 251-256.

Review article
Published: 09 January 2017 in Journal of Agricultural and Food Chemistry
Reads 0
Downloads 0

Cereal grains and their processed food products are frequently contaminated with mycotoxins. Among many, five major mycotoxins of aflatoxins, ochratoxins, fumonisins, deoxynivalenol, and zearalenone are of significant public health concern as they can cause adverse effects in humans. Being airborne or soilborne, the cosmopolitan nature of mycotoxigenic fungi contribute to the worldwide occurrence of mycotoxins. On the basis of the global occurrence data reported during the past 10 years, the incidences and maximum levels in raw cereal grains were 55% and 1642 μg/kg for aflatoxins, 29% and 1164 μg/kg for ochratoxin A, 61% and 71,121 μg/kg for fumonisins, 58% and 41,157 μg/kg, for deoxynivalenol, and 46% and 3049 μg/kg for zearalenone. The concentrations of mycotoxins tend to be lower in processed food products; the incidences varied depending on the individual mycotoxins, possibly due to the varying stability during processing and distribution of mycotoxins. It should be noted that more than one mycotoxin, produced by a single or several fungal species, may occur in various combinations in a given sample or food. Most studies reported additive or synergistic effects, suggesting that these mixtures may pose a significant threat to public health, particularly to infants and young children. Therefore, information on the co-occurrence of mycotoxins and their interactive toxicity is summarized in this paper.

ACS Style

Hyun Jung Lee; Dojin Ryu. Worldwide Occurrence of Mycotoxins in Cereals and Cereal-Derived Food Products: Public Health Perspectives of Their Co-occurrence. Journal of Agricultural and Food Chemistry 2017, 65, 7034 -7051.

AMA Style

Hyun Jung Lee, Dojin Ryu. Worldwide Occurrence of Mycotoxins in Cereals and Cereal-Derived Food Products: Public Health Perspectives of Their Co-occurrence. Journal of Agricultural and Food Chemistry. 2017; 65 (33):7034-7051.

Chicago/Turabian Style

Hyun Jung Lee; Dojin Ryu. 2017. "Worldwide Occurrence of Mycotoxins in Cereals and Cereal-Derived Food Products: Public Health Perspectives of Their Co-occurrence." Journal of Agricultural and Food Chemistry 65, no. 33: 7034-7051.

Journal article
Published: 01 January 2017 in Food Chemistry
Reads 0
Downloads 0

Ochratoxin A (OTA) is a fungal metabolite and putative carcinogen which can contaminate a variety of foods such as cereals, wine, and nuts. Commercial ELISA kits are known to give false-positive results for OTA concentrations when phenolic compounds are present. Pistachios represent a food matrix rich in phenolic compounds potentially contaminated with OTA, and were used to model OTA cross-reactivity. Polyvinylpolypyrrolidone (PVPP) was incorporated during extraction of OTA using a commercial ELISA protocol. HPLC methods were used to confirm that PVPP does not interact with OTA and levels of gallic acid and catechin remaining in pistachio extracts decreased with increasing PVPP application. Cross-reactivity of extracts also decreased with increasing PVPP application, and color loss was used as an indicator of anthocyanin removal. Incorporating PVPP into ELISA protocols allows for the continued use of rapid immunological methods in food matrices containing phenolic compounds.

ACS Style

Andrew L. Robinson; Hyun Jung Lee; Dojin Ryu. Polyvinylpolypyrrolidone reduces cross-reactions between antibodies and phenolic compounds in an enzyme-linked immunosorbent assay for the detection of ochratoxin A. Food Chemistry 2017, 214, 47 -52.

AMA Style

Andrew L. Robinson, Hyun Jung Lee, Dojin Ryu. Polyvinylpolypyrrolidone reduces cross-reactions between antibodies and phenolic compounds in an enzyme-linked immunosorbent assay for the detection of ochratoxin A. Food Chemistry. 2017; 214 ():47-52.

Chicago/Turabian Style

Andrew L. Robinson; Hyun Jung Lee; Dojin Ryu. 2017. "Polyvinylpolypyrrolidone reduces cross-reactions between antibodies and phenolic compounds in an enzyme-linked immunosorbent assay for the detection of ochratoxin A." Food Chemistry 214, no. : 47-52.

Journal article
Published: 01 October 2016 in Journal of Food Protection
Reads 0
Downloads 0

Ochratoxin A (OTA) represents one of the most widespread mycotoxins in agricultural commodities in the world and is considered a possible human carcinogen with its potent nephrotoxicity. OTA is stable under most food processing conditions; however, higher-temperature treatment may reduce OTA content in foods. Since OTA can be found in processed products destined for both human and animal consumption, factors affecting its stability or reduction during thermal processes were investigated here. The reduction of OTA was measured during various heating times (up to 60 min) at different temperatures (100, 125, 150, 175, and 200°C) in aqueous buffer solutions at different pHs (pH 4, 7, and 10). Quantification of OTA was carried out using high-performance liquid chromatography with fluorescence detection. The results showed that the rate and extent of OTA reduction were dependent on pH, processing time, and temperature; greater than 90% OTA reduction was achieved at 200°C for all treatments except pH 4. After processing under an alkaline condition (pH 10) at 100°C for 60 min, about 50% of the OTA was lost, while after 60 min under neutral and acidic conditions at 100°C, significant reductions of OTA were not shown.

ACS Style

Samjhana Dahal; Hyun Jung Lee; Kejia Gu; Dojin Ryu. Heat Stability of Ochratoxin A in an Aqueous Buffered Model System. Journal of Food Protection 2016, 79, 1748 -1752.

AMA Style

Samjhana Dahal, Hyun Jung Lee, Kejia Gu, Dojin Ryu. Heat Stability of Ochratoxin A in an Aqueous Buffered Model System. Journal of Food Protection. 2016; 79 (10):1748-1752.

Chicago/Turabian Style

Samjhana Dahal; Hyun Jung Lee; Kejia Gu; Dojin Ryu. 2016. "Heat Stability of Ochratoxin A in an Aqueous Buffered Model System." Journal of Food Protection 79, no. 10: 1748-1752.

Journal article
Published: 16 September 2016 in Journal of Agricultural and Food Chemistry
Reads 0
Downloads 0

A symposium entitled "Public Health Perspectives of Mycotoxins in Food" was held at the 251st American Chemical Society Meeting in March 2016 in San Diego, CA and was sponsored by the ACS Division of Agricultural and Food Chemistry. The purpose of the symposium was to convene the leading mycotoxin researchers throughout the world to discuss the current state of knowledge as well as research needs with respect to evaluating the toxicological properties of mycotoxins, and ways to detect, control and reduce human and animal exposure to these natural toxins. Twenty-three presentations were delivered by speakers representing academic, government and industrial institutions from North America, Europe, Asia and Africa. The presentations covered such diverse topics as a historical perspective on the discovery of the major fungal toxins, occurrence of mycotoxins in food and feed, toxicological properties of mycotoxins and their influence on public health, analytical methods for mycotoxins, pre- and post-harvest control of mycotoxins, and regulatory aspects. This article is intended to provide a brief summary of the presentations as well as a record of the proceedings of the symposium.

ACS Style

Lauren S. Jackson; Dojin Ryu. Summary of the ACS Symposium on Public Health Perspectives of Mycotoxins in Food. Journal of Agricultural and Food Chemistry 2016, 65, 7017 -7020.

AMA Style

Lauren S. Jackson, Dojin Ryu. Summary of the ACS Symposium on Public Health Perspectives of Mycotoxins in Food. Journal of Agricultural and Food Chemistry. 2016; 65 (33):7017-7020.

Chicago/Turabian Style

Lauren S. Jackson; Dojin Ryu. 2016. "Summary of the ACS Symposium on Public Health Perspectives of Mycotoxins in Food." Journal of Agricultural and Food Chemistry 65, no. 33: 7017-7020.

Evaluation study
Published: 01 February 2016 in Journal of Food Protection
Reads 0
Downloads 0

Hand washing and glove use are the main methods for reducing bacterial cross-contamination from hands to ready-to-eat food in a food service setting. However, bacterial transfer from hands to gloves is poorly understood, as is the effect of different durations of soap rubbing on bacterial reduction. To assess bacterial transfer from hands to gloves and to compare bacterial transfer rates to food after different soap washing times and glove use, participants' hands were artificially contaminated with Enterobacter aerogenes B199A at ~9 log CFU. Different soap rubbing times (0, 3, and 20 s), glove use, and tomato dicing activities followed. The bacterial counts in diced tomatoes and on participants' hands and gloves were then analyzed. Different soap rubbing times did not significantly change the amount of bacteria recovered from participants' hands. Dicing tomatoes with bare hands after 20 s of soap rubbing transferred significantly less bacteria (P < 0.01) to tomatoes than did dicing with bare hands after 0 s of soap rubbing. Wearing gloves while dicing greatly reduced the incidence of contaminated tomato samples compared with dicing with bare hands. Increasing soap washing time decreased the incidence of bacteria recovered from outside glove surfaces (P < 0.05). These results highlight that both glove use and adequate hand washing are necessary to reduce bacterial cross-contamination in food service environments.

ACS Style

Andrew L. Robinson; Hyun Jung Lee; Junehee Kwon; Ewen Todd; Fernando Perez Rodriguez; Dojin Ryu. Adequate Hand Washing and Glove Use Are Necessary To Reduce Cross-Contamination from Hands with High Bacterial Loads. Journal of Food Protection 2016, 79, 304 -308.

AMA Style

Andrew L. Robinson, Hyun Jung Lee, Junehee Kwon, Ewen Todd, Fernando Perez Rodriguez, Dojin Ryu. Adequate Hand Washing and Glove Use Are Necessary To Reduce Cross-Contamination from Hands with High Bacterial Loads. Journal of Food Protection. 2016; 79 (2):304-308.

Chicago/Turabian Style

Andrew L. Robinson; Hyun Jung Lee; Junehee Kwon; Ewen Todd; Fernando Perez Rodriguez; Dojin Ryu. 2016. "Adequate Hand Washing and Glove Use Are Necessary To Reduce Cross-Contamination from Hands with High Bacterial Loads." Journal of Food Protection 79, no. 2: 304-308.

Corrected and republished article
Published: 13 November 2015 in Journal of Food Science
Reads 0
Downloads 0

Aflatoxins, ochratoxins, fumonisins, deoxynivalenol, and zearalenone are of significant public health concern as they can cause serious adverse effects in different organs including the liver, kidney, and immune system in humans. These toxic secondary metabolites are produced by filamentous fungi mainly in the genus Aspergillus, Penicillium, and Fusarium. It is challenging to control the formation of mycotoxins due to the worldwide occurrence of these fungi in food and the environment. In addition to raw agricultural commodities, mycotoxins tend to remain in finished food products as they may not be destroyed by conventional processing techniques. Hence, much of our concern is directed to chronic health effects through long-term exposure to one or multiple mycotoxins from contaminated foods. Ideally risk assessment requires a comprehensive data, including toxicological and epidemiological studies as well as surveillance and exposure assessment. Setting of regulatory limits for mycotoxins is considered necessary to protect human health from mycotoxin exposure. Although advances in analytical techniques provide basic yet critical tool in regulation as well as all aspects of scientific research, it has been acknowledged that different forms of mycotoxins such as analogs and conjugated mycotoxins may constitute a significant source of dietary exposure. Further studies should be warranted to correlate mycotoxin exposure and human health possibly via identification and validation of suitable biomarkers.

ACS Style

Hyun Jung Lee; Dojin Ryu. Advances in Mycotoxin Research: Public Health Perspectives. Journal of Food Science 2015, 80, T2970 -T2983.

AMA Style

Hyun Jung Lee, Dojin Ryu. Advances in Mycotoxin Research: Public Health Perspectives. Journal of Food Science. 2015; 80 (12):T2970-T2983.

Chicago/Turabian Style

Hyun Jung Lee; Dojin Ryu. 2015. "Advances in Mycotoxin Research: Public Health Perspectives." Journal of Food Science 80, no. 12: T2970-T2983.

Journal article
Published: 01 July 2015 in Journal of Food Protection
Reads 0
Downloads 0

Cereal grains are a significant source of ochratoxin A (OTA) in the human diet. Multiple ochratoxigenic Aspergillus and Penicillium spp. have been reported as contaminants on various cereal grains around the world, although relatively few species dominate in any given location. Efforts to mitigate the risk of fungal contamination and OTA accumulation can be made pre- and postharvest. Still, a rapid and reliable screening method is sought that can be used to predict the OTA level of a sample and to inform risk assessments prior to processing. In this study, we assessed the efficacy of two OTA-related indices for OTA level prediction. Infestation rates were determined by direct plating for freshly harvested and stored barley, durum, and hard red spring wheat samples (n = 139) with known OTA levels. Presumptive ochratoxigenic isolates were tested for their ability to produce OTA. The nonribosomal peptide synthase (otanpsPN) involved in OTA biosynthesis was used to quantify ochratoxigenic fungi in barley and wheat. Viable Penicillium verrucosum was present in 45% of the samples. In total, 62.7% (n = 110) of the P. verrucosum isolates tested produced OTA on dichloran yeast extract sucrose 18% glycerol agar. Both OTA level and infestation rate (r = 0.30), as well as OTA level and otanpsPN concentration (r = 0.56), were weakly correlated. Neither infestation rate nor otanpsPN concentration is a reliable predictor of OTA level in a sample.

ACS Style

Julie Kuruc; Justin Hegstad; Hyun Jung Lee; Kristin Simons; Dojin Ryu; Charlene Wolf-Hall. Infestation and Quantification of Ochratoxigenic Fungi in Barley and Wheat Naturally Contaminated with Ochratoxin A. Journal of Food Protection 2015, 78, 1350 -1356.

AMA Style

Julie Kuruc, Justin Hegstad, Hyun Jung Lee, Kristin Simons, Dojin Ryu, Charlene Wolf-Hall. Infestation and Quantification of Ochratoxigenic Fungi in Barley and Wheat Naturally Contaminated with Ochratoxin A. Journal of Food Protection. 2015; 78 (7):1350-1356.

Chicago/Turabian Style

Julie Kuruc; Justin Hegstad; Hyun Jung Lee; Kristin Simons; Dojin Ryu; Charlene Wolf-Hall. 2015. "Infestation and Quantification of Ochratoxigenic Fungi in Barley and Wheat Naturally Contaminated with Ochratoxin A." Journal of Food Protection 78, no. 7: 1350-1356.