Determination of ochratoxin A in Vitis labrusca musts: analytical performance and occurrence in Southern Brazil

Biological removal of ochratoxin A (OTA) by living and heat-treated dead conidia of black Aspergillus isolates representing the species Aspergillus niger, Aspergillus carbonarius, and Aspergillus japonicus in synthetic and natural grape juices was found to be a two-stage phenomenon. Several lines of evidence suggest that the first observed stage was passive, metabolism was not required, and OTA adsorption on conidia of black aspergilli could be involved. This removal was fast, without delay just after conidial inoculation both in synthetic and natural grape juices. Moreover, even nonviable, heat-treated conidia were capable of removing OTA. Finally, no OTA degradation products were detected. In the second observed stage, removal of OTA was linked to degradation by live conidia only. Ochratoxin alpha, a degradation product of OTA, was detected in the medium after incubation for 30 and 14 h for biseriate (A. niger and A. carbonarius) and uniseriate (A. japonicus) black aspergilli, respectively, when well-developed mycelium appeared. Comparisons between the three black Aspergillus isolates tested showed that A. carbonarius detoxified grape juice most effectively. However, this species often produces OTA. A. niger and A. japonicus isolates were also effective and because those species are not systematically OTA producers, they could be interesting for further OTA detoxification processes in grape juices and musts.

Worldwide interlaboratory study on the determination of ochratoxin A in different wine type samples

Ochratoxin A (OTA) is one of the most prevalent mycotoxin contaminants of food crops. Among the agricultural products consequently contaminated by OTA is wine. In the present study, a sample of wines sourced from the United States was assessed for OTA. Wines were primarily analyzed by high-performance liquid chromatography with fluorescence detection (HPLC-FD) coupled to a liquid-liquid extraction (LLE) technique which was developed and validated as a simplified sample preparation approach. More than 85% of the wines evaluated were found to contain OTA, at levels above the limit-of-detection (LOD = 0.1 µg L−1), and 76% were above the limit-of-quantitation (LOQ = 0.3 µg L−1) for the LLE/HPLC-FD method. More than two-thirds of the wines above the LOQ were found to exceed 1 µg L−1. Complementary analysis by HPLC coupled to tandem mass spectrometry (HPLC-MS/MS) confirmed OTA in 74% of the OTA-positive wines (i.e., >LOQ by HPLC-FD). Overall, both the occurrence and measured levels of OTA were generally high, specifically relative to previous assessments of OTA in wine, and two of the wines were above the only current (European Union) regulatory limit of two parts-per-billion (ppb, ~2 µg L−1). Possible trends with respect to geographical region and/or growing climate are noted. As the first assessment of U.S. wines in more than a decade, the overall high occurrence and levels of OTA in wine, and possible geographic and climatic trends, point to a need for regular surveillance of wines, as well as investigation of the relevant contributors to OTA occurrence toward mitigating contamination and exposure risks.

A new method was developed for the rapid analysis of ochratoxin A (OTA) in pig muscle using dispersive liquid-liquid microextraction (DLLME) combined with high-performance liquid chromatography (HPLC). OTA was extracted with methanol and then cleaned up with DLLME procedure. After being blown dry and redissolved, the sample was determined using high-performance liquid chromatography with fluorescence detector (HPLC-FLD). Under the experimental conditions, the LOD was 0.21 μg kg−1, LOQ was 0.70 μg kg−1, and the recovery was higher than 80 %. Intra- and inter-day repeatability expressed as RSD were less than 5 %. The established method is more efficient, easier, and cheaper than conventional cleaning up procedure.

PurposeWith the present work, we aimed to assess the occurrence of ochratoxigenic fungi and Ochratoxin A (OTA) in dried grapes from Tunisia.MethodsDried grapes samples (n = 90) were investigated for the presence of ochratoxigenic fungi, which were further characterized at the species level through amplification of the internal transcribed spacer (ITS) region and polymerase chain reaction (PCR) product sequencing. Fungal isolates were tested for their ochratoxigenic potential by high-performance liquid chromatography with fluorescence detection (HPLC-FLD), as well as dried grapes samples after an immunoaffinity column (IAC) clean-up procedure.ResultsBlack Aspergilli isolates were the dominant genre among the filamentous fungi found in dried grapes samples and were the only OTA-producing fungi encountered. Aspergillus niger aggregate were the most frequently found isolates reaching 70%, 80%, and 85% in dried grapes samples from regions of Kelibia, Sfax, and Rafraf, respectively, while covered 100% of the relevant mycobiota found in imported samples. Aspergillus carbonarius isolates were found only in Sfax’s and Kelibia’s samples, while uniseriate Aspergilli were found between 7 and 20% in dried grapes from Kelibia, Sfax, and the imported samples. The in vitro OTA production test showed that 88.9% of OTA-producing isolates belonged to A. carbonarius with OTA levels varying from 0.06 to 1.32 μg/g of Czapek Yeast Agar (CYA). The remaining OTA-producing fungi (11.1 %) belonged to A. niger aggregate group having a maximum OTA potential of 2.88 μg/g CYA, and no uniseriate Aspergilli isolate was able to produce OTA. All dried grapes samples were free of OTA presence.ConclusionAccording to the present study’s findings, no OTA contamination was recorded in the investigated samples from Tunisian market. Nevertheless, the presence of strong OTA producers A. carbonarius in samples originated from the two out of three studied Tunisian regions, as well the high incidences of Aspergillus niger aggregate group with an attested potential for OTA production in all samples, necessitates further research on Tunisian dried grapes. Additionally, a continuous analysis of staple food of the Mediterranean diet is imperative to insure the best quality for the consumers and prevent potential health problems.

This study aimed to assess the presence of ochratoxin A (OTA) residues in the blood serum of slaughtered pigs in Greece. Samples were obtained from 1695 healthy slaughtered pigs originating from 113 different farms located in 21 geographic regional units in 8 different geographic regions of Greece and were analyzed using an immunosorbent assay (ELISA) and high-performance liquid chromatography with fluorescence detector (HPLC-FD). OTA contamination assessment showed that 782 (46.1%) and 1233 (72.7%) samples were OTA-positive, with a concentration range of 0.20–5.38 μg/L and 0.15–5.96 µg/L according to ELISA and HPLC-FD analysis, respectively. Also, 88 (77.9%) and 108 (95.6%) of farms were found to be OTA-positive by ELISA and HPLC-FD analysis, respectively. The highest OTA serum positivity rate (>98%) and toxin level (5.96 µg/L) determined by HPLC-FD were observed in the Thessaly region, whereas a high prevalence of up to 100% (range 75–100%) was found on farms in the Crete Island region. The detection of OTA in the serum of slaughtered pigs in different regions in Greece poses a risk for animal and human health and highlights the need for constant OTA monitoring in the swine industry and pork meat production facilities.

Occurrence of ochratoxin A in Turkish wines

Background Ochratoxin is a potent human toxin and suspected carcinogen metabolite generated by Penicillium spp. and Aspergillus spp. The current systematic meta-analysis review was conducted for the first time on the prevalence of ochratoxin A (OTA) in dried grapes and grape-derived products including sultana, currant, raisin, pekmez, and grape juice. Methods All studies published up to December 2019 were searched in PubMed, Scopus, and Web of Science databases. The references of published papers were collected in order to investigate the prevalence of OTA in dried grapes and grape-derived products. The degree of heterogeneity between the studies was evaluated by the I2 heterogeneity statistic. The random effects model was used to calculate the pooled prevalence in subgroups such as country and type of grape products. Results The search retrieved 725 studies, 39 of which were included in this meta-analysis. According to reviewed reports, the global pooled prevalence of OTA was estimated as 42% (95% CI: 32%, 52%) for currants, 36% (95% CI: 20%, 52%) for grape juice, 39% (95% CI: 28%, 50%) for pekmez, 58% (95% CI: 48%, 68%) for raisins, and 27% (95% CI: 22%, 33%) for sultana. The rank of grape-based products based on mean concentration of OAT was in order of pekmez > raisin > sultana > currant > grape juice. Conclusion The lowest and highest prevalence of OTA in different studied samples were related to grape juice and pekmez, respectively. The results of this meta-analysis can be useful in different risks management models, and can help health strategists and different industries to reduce the prevalence of OTA in grape-based products.

Sleep on it: Everything will look better in the morning

An extensive survey of filamentous fungi isolated from wheat grown and consumed in Lebanon and their capacity to produce aflatoxin B1 (AFB1) and ochratoxin A (OTA) was conducted to assess fungi potential for producing these toxins in wheat. From the 468 samples of wheat kernel, collected at preharvest stage from different locations during 2008 and 2009 cultivation seasons, 3,260 fungi strains were isolated with 49.4% belonging to Penicillium spp. and 31.2% belonging to Aspergillus spp. Penicillium spp. was detected on wheat samples with a high amount of P. verrucosum (37.0%). Among the different Aspergillus spp. isolated, A. niger aggregate was predominant and constituted 37.3%. whereas the isolation rate of A. flavus and A. ochraceus was 32.2 and 25.6%, respectively. The ability to produce OTA and AFB1 by isolates belonging to Aspergillus spp. and Penicillium spp. was analyzed by high performance liquid chromatography with fluorescence detector (HPLC-FLD). It was found that 57.0% of Penicillium spp. and 80% of A. ochraceus isolates tested produced OTA, respectively, at maximum concentrations of 53 and 65μg/g CYA. As for the aflatoxinogenic ability, 45.3% of A. flavus produced AFB1, with maximum concentration of 40μg/g CYA. A total of 156 wheat samples were analyzed for the levels of OTA and AFB1 by HPLC-FLD. The results showed that 23.7% were contaminated with OTA, at a concentration higher than 3μg/kg and 35.2% of these samples were contaminated with AFB1 at concentration higher than 2μg/kg. The risks originating from toxin levels in wheat produced in Lebanon should be monitored to prevent their harmful effects on public health.

Ochratoxin A (OTA) is a very dangerous mycotoxin, the presence of which is often reported in different foods, as well as in beverages such as grapes, grape juices and wines. Detoxifying these products is therefore of prime importance in protecting consumer health, and biological approaches have been the most promising methods. In this report, 40 isolates representing the black apergilli species Aspergillus carbonarius, A. niger aggregate and A. japonicus, isolated on French grapes, were assessed for OTA degradation capacities in CZAPEK yeast extract broth (CYB) and in a synthetic grape juice medium (SGM) contaminated with OTA at 2 mg L(-1) (5 microM). It was clearly observed that in both media these fungi had the ability to degrade OTA to OTalpha (ochratoxinalpha). However, there were differences between the media used and species tested during OTA degradation. In SGM and CYB, 77% and 45% of the isolates, respectively were able to degrade more than 80% of the OTA. Despite a better growth on SGM, specific OTA degradation was higher on CYB for most of the isolates. Kinetic studies carried out on SGM with three black Aspergillus isolates all showed different OTA degradation rates. After 9 days of incubation, OTalpha had decreased, whereas an unknown compound appeared. A. niger could be the first interesting species for OTA detoxification processes, followed by A. japonicus.

A Rapid High-Performance Liquid Chromatography with Fluorescence Detection Method Developed To Analyze Ochratoxin A in Wine

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.

Human exposure to ochratoxin A and its natural occurrence in spices marketed in Chile (2016–2020): A case study of merkén

Comparison of aflatoxins and ochratoxin A contaminated in homemade and commercial doenjang manufactured by traditional and modified methods