Ochratoxin A in dried grapes in Hamadan province, Iran

Molecular identification and biocontrol of ochratoxigenic fungi and ochratoxin A in animal feed marketed in the state of Qatar

Ochratoxin A (OTA) is a toxic fungal metabolite produced by some Aspergillus and Penicillium species. This work was designed to explore the presence of OTA and ochratoxigenic fungi in feed grains marketed in Qatar and their biological control by a bacterium (Burkholderia cepacia). Significantly higher levels of OTA were detected in mixed grains samples (144.59 ± 6.63 μg/kg), compared to the maize (25.27 ± 1.89 μg/kg) and wheat (3.37 ± 0.11 μg/kg). OTA-producing fungi (A. niger, A. ochraceus, A. westerdijkiae, A. carbonarius and P. verrucosum) were identified on the basis of their morphological features as well as through polymerase chain reaction (PCR). Putative ochratoxigenic polyketide genes in these isolates were evidenced by using primers AoOTA-L/AoOTA-R (in A. ochraceus and A. westerdijkiae), AoPks1/AoPks2 (in A. niger and A. ochraceus) and PenPks1/Penpks2 (in P. verrucosum). On synthetic media, A. westerdijkiae showed the highest OTA synthesis (5913 ± 576 μg/kg) than the closely related A. ochraceus (3520 ± 303 μg/kg), A. carbonarius (3064 ± 289 μg/kg) and P. verrucosum (3030 ± 710 μg/kg). Burkholderia cepacia cells and culture extract showed promising biological control potentials against OTA producing fungi. On the basis of these findings, it can be concluded that animal feed samples are generally contaminated with OTA-producing fungi as well as OTA, and Burkholderia cepacia CS5 exhibits promising antifungal activities.

Removal of Ochratoxin A from Grape Juice by Clarification: A Response Surface Methodology Study

This study achieved maximum removal of ochratoxin A (OTA) during the grape juice clarification process with minimal reduction in antioxidant compounds (phenolic acid, flavonoids, and antioxidant capacity by FRAP) by the RSM method. Independent variables included three types of clarifiers—gelatin, bentonite, and diatomite (diatomaceous earth)—at a concentration level of 0.25–0.75% and clarification time of 1–3 h. OTA was measured by high-performance liquid chromatography with fluorescence detection. Clarifying agent concentration and clarification time affected the reduction amount of OTA and antioxidant compounds in grape juice. There was a direct linear correlation between the reduction amounts of OTA and antioxidant compounds and capacity with the concentration of bentonite, gelatin, and diatomite, and the clarification time. The reduction amount of OTA and antioxidant capacity followed the linear mode. However, the decreased phenolic acid and flavonoid values followed the quadratic model. The study results showed that if the concentrations of bentonite, gelatin, and diatomite and clarification time were 0.45, 0.62, 0.25%, and 1 h, respectively, the maximum amount of OTA reduction (41.67%) occurred. Furthermore, the phenolic acid, flavonoid, and antioxidant activity decrease amounts were at their lowest levels, i.e., 23.86, 7.20, and 17.27%, respectively.

The Occurrence and Contamination Level of Ochratoxin A in Plant and Animal-Derived Food Commodities

Ochratoxin A (OTA) is a highly toxic mycotoxin and poses great threat to human health. Due to its serious toxicity and widespread contamination, great efforts have been made to evaluate its human exposure. This review focuses on the OTA occurrence and contamination level in nine plant and animal derived food commodities: cereal, wine, coffee, beer, cocoa, dried fruit, spice, meat, and milk. The occurrence and contamination level varied greatly in food commodities and were affected by many factors, including spices, geography, climate, and storage conditions. Therefore, risk monitoring must be routinely implemented to ensure minimal OTA intake and food safety.

Aflatoxins in randomly selected groundnuts (Arachis hypogaea) and its products from some local markets across Ghana: Human risk assessment and monitoring

A random assessment and human risk analysis were conducted on 80 groundnut pastes and raw groundnuts from some local markets across the different agroecological zones of Ghana. Total aflatoxins (AFtotal) and aflatoxins (AFB₁, AFB₂, AFG₁, and AFG₂) were analyzed using the High-Performance Liquid Chromatography (HPLC) method. Out of 80 samples investigated, 49 (61.25 %) tested positive for AFB₁ and ranged from 0.38 ± 0.04-230.21 ± 22.14 μg/kg. The same proportion was recorded for total aflatoxins (AF_total) and ranged between 0.38 ± 0.02-270.51 ± 23.14 μg/kg. Limits of AFB₁ and total aflatoxins (AFtotal) for the Ghana Standards Authority (GSA) (5 and 10 μg/kg) and the European Food Safety Authority (EFSA) (2 and 4 μg/kg), were used as checks. A total of 33 (41.25 %) samples were above the limits for both. Risk assessments recorded for Estimated Daily Intake (EDI), Margin of Exposure (MOE), potency, cancer risk, and population risks ranged 0.087-0.380 μg/Kg.bw/day, 1052.630-4597.700, 0-0.00396 ng Aflatoxins kg^-1bwday^-1 and, 1.5 × 10^-3 - 7.9 × 10^-4 respectively for total aflatoxins. While for aflatoxins B₁ (AFB₁), ranges of values of 0.068-0.300 μg/Kg.bw/day, 1333.33-5882.35, 0-0.00396 ng aflatoxins kg/bw/day and, 1.19 × 10^-3 - 6.34 × 10^-4 corresponded for Estimated Daily Intake (EDI), Margin of Exposure (MOE), potency, cancer risk, and population risk respectively. There were risks of adverse health effects involved in the consumption of groundnuts for all age groups investigated since MOE values were all below 10,000.

Genetic Diversity, Ochratoxin A and Fumonisin Profiles of Strains of Aspergillus Section Nigri Isolated from Dried Vine Fruits

We investigated ochratoxin A (OTA) contamination in raisin samples purchased from Slovak markets and determined the diversity of black-spored aspergilli as potential OTA and fumonisin (FB1 and FB2) producers. The taxonomic identification was performed using sequences of the nuclear ITS1-5.8s-ITS2 region, the calmodulin and beta-tubulin genes. We obtained 239 isolates from eight fungal genera, of which 197 belonged to Aspergillus (82%) and 42 strains (18%) to other fungal genera. OTA contamination was evidenced in 75% of the samples and its level ranged from 0.8 to 10.6 µg/kg. The combination of all three markers used enabled unambiguous identification of A. carbonarius, A. luchuensis, A. niger, A. tubingensis and A. welwitschiae. The dominant coloniser, simultaneously having the highest within-species diversity isolated from our raisin samples, was A. tubingensis. Out of all analysed strains, only A. carbonarius was found to produce OTA, but in relatively high quantity (2477–4382 µg/kg). The production of FB1 and FB2 was evidenced in A. niger strains only.

A preliminary assessment of dietary exposure of ochratoxin A in Central Anatolia Region, Turkey

The aim of this study was to determine dietary exposure to ochratoxin A (OTA) in Turkish adults. In this study, 500 food samples (50 rice, 50 wheat bread, 50 pasta, 50 raisins, 50 dried figs, 50 pistachios, 50 hazelnuts, 50 almonds, 50 chilli, 25 coffee, and 25 cocoa) collected from Turkey were analysed with a high-performance liquid chromatography (HPLC) method. Moreover, a total of 370 analytical results (110 cereal-based snacks, 95 wine, 35 beer, and 130 chocolate) collected from our previous observations were also used in the evaluation of exposure estimates. OTA was found in 52% of cocoa, 42% of raisins, 40% of coffee, 34% of chilli, 14% of dried figs, 10% of pasta, 8% of pistachios, 6% of wheat bread, 4% of rice, and 4% of hazelnuts. The chronic dietary exposure to OTA for Turkish adults, using lower bound (LB) and upper bound (UB) concentrations, varied from 0.683 to 4.487 ng/kg body weight (b.w.) per week for mean estimate and from 3.976 to 5.760 ng/kg b.w. per week for the 95th percentile (P95) estimate. Cereals and cereal-based products made the largest contribution (75.3-85.7%) to OTA exposure. Both mean and P95 chronic exposure to OTA were greatly below the tolerable weekly intake of 120 ng/kg b.w. per week and thus not a health concern for Turkish adults.

The Occurrence and Risk Assessment of Exposure to Aflatoxin M1 in Ultra-High Temperature and Pasteurized Milk in Hamadan Province of Iran

Objectives

Aflatoxins are a category of poisonous compounds found in most plants, milk and dairy products. The present research was carried out to detect the presence of aflatoxin M₁ (AFM₁) in samples of milk collected from Hamadan province, Iran.

Methods

Twenty five samples of ultra-high temperature (UHT) and 63 samples of pasteurized milk were collected and the amount of AFM₁ was measured by an Enzyme-Linked Immunosorbent Assay method. In addition, the estimated daily intake (EDI) and hazard index (HI) of AFM₁ was determined by the following equations:(EDI= mean concentration of AFM₁ × daily consumption of milk/body weight; HI= EDI/Tolerance Daily Intake).

Results

AFM₁ was detected in 21 (84%) UHT milk samples and in 55 (87.30%) pasteurized milk samples. Seven (28%) samples of UHT and 21 (33.33%) pasteurized milk samples had higher AFM₁ content than the limit allowed in the European Union and Iranian National Standard Limits (0.05 μg/kg). None of the samples exceeded the US Food and Drug Administration limit (0.5 μg/kg) for AFM₁. EDI and HI for AM₁ through milk were 0.107 ng/kg body weight/day, and 0.535, respectively.

Conclusion

A significant percentage of milk produced by different factories in Iran (84% of UHT and 87.3% of pasteurized milk) was contaminated with AFM₁. Therefore, more control and monitoring of livestock feeding in dairy companies may help reduce milk contamination with AFM₁. As the HI value was lower than 1, it can be assumed that there was no risk of developing liver cancer due to milk consumption.

The influence of yeast level and fermentation temperature on Ochratoxin A decrement during bread making

Ochratoxin A (OTA) occurrence in cereals is a permanent challenge in human health. In recent years, some studies have focused on the role of yeasts as adsorbing tools to eliminate OTA. The aim of the current research was to study the effects of different variables including Saccharomyces cerevisiae amount and the fermentation temperature on the reduction of OTA during bread baking. For this purpose, the OTA was spiked to the flour and then the bread was prepared. OTA levels in flour, dough, and bread were measured by the high-performance liquid chromatography with fluorescence detector (HPLC-FD). The results revealed that yeast level and fermentation temperature had a significant effect on OTA reduction. The increase of the amount of S. cerevisiae from 1% to 2% w/w and the fermentation temperature from 25ºC to 30ºC resulted in the increment of OTA reduction from 31.17% to 59.41%. During baking, OTA reduction was 19.21%. In general, the utilization of 2% w/w S. cerevisiae and the fermentation temperature of 35 ºC could reduce considerable amount of OTA in the wheat bread.

Optimization of washing and cooking processes of rice for Ochratoxin A decrement by RSM

In this research, effects of washing and cooking processes on the decrease in ochratoxin A (OTA) residue in rice were investigated. Rice samples were washed one, two, and three times in the washing stage. Results showed that the washing stage was effective on OTA residue as 42.68% of OTA was removed. In the cooking stage, the effects of boiling time, salt content, and water-to-rice ratio on OTA residue were studied employing response surface methodology (RSM). The results showed that time and salt content, interaction between time and salt content, and interaction between salt content and water-to-rice ratio were effective on the amount of OTA residue. According to the results, the optimum levels for boiling time, salt content, and water-to-rice ratio were 9.6 min, 3.5% salt, and 4:1, respectively. At these conditions, 76% of the OTA in rice was reduced.

Citrinin detection by intensified fluorescence signal of a FRET-based immunosensor using magnetic/silica core-shell

The specific immune-reaction between the anti-citrinin antibody immobilized on the surface of magnetic/silica core–shell (MSCS) and the citrinin–Rho123–BSA conjugate brings the Rho123 fluorophore as an acceptor and the QDs as a donor in close spatial proximity and causes FRET for occurring upon photo-excitation of the QDs. The novelties of this study include: (1) immobilization of the MSCS; (2) large amount of the immobilized QDs, and (3) immobilization of a large amount of Rho123 on the BSA macromolecule. Cd/Te QDs were synthesized by the simultaneous reduction of cadmium chloride and tellurium in the presence of sodium borohydride. Magnetic nanoparticles were synthesized using FeSO₄ and FeCl₃. The prepared magnetic nanoparticles shelled by silica using tetraethoxysilane in the presence of ammonia. Transmission electron microscopy (TEM) analysis was used for investigating shape and monodispersity of the nanoparticles. EDC/NHS was used as a cross linking agent for immobilization of the QDs, conjugation of citrinin to amino groups of BSA, labeling of BSA with Rho123 and also for immobilization of the amino-functionalized MSCS on the immobilized QDs. Immobilization of the anti-citrinin antibody on the surface of the amino-functionalized MSCS was performed by Schiff-base mechanism. By using these three effective strategies, sensitivity of the designed nanobiosensor was incredibly enhanced as a very low limit of detection (up to 0.1 pM). The feasibility of this technique was tested by the detection of citrinin in the spiked human serum. Results showed that there was a linear correlation between the decreased fluorescence intensity of the Rho123 and increased fluorescence intensity of the QDs with increasing concentration of citrinin in the spiked samples in the range of 1–6 pM. According to obtained results, we conclude that this highly sensitive detection scheme is a easy, quick and impressive method that can be used in optical-based nanosensors.