Mycotoxin production in amber durum wheat stored at 15 and 19% moisture content

Adding genistein or luteolin decreased the yield of citrinin and without reducing pigments in yam solid-fermentation by Monascus

BACKGROUND

Chinese yam fermented by Monascus, namely red mold dioscorea (RMD), has the potential of treating diseases. However, the production of citrinin limits the application of RMD. In the present study, the fermentation process of Monascus was optimized by adding genistein or luteolin to reduce citrinin yield.

RESULTS

The results showed that citrinin in 25 g of Huai Shan yam was reduced by 48% and 72% without affecting the pigment yield by adding 0.2 g of luteolin or genistein, respectively, to a 250-mL conical flask after fermentation for 18 days at 28 °C, whereas the addition of luteolin increased the content of yellow pigment by 1.3-fold. Under optimal conditions, citrinin in 20 g of iron bar yam decreased by 55% and 74% after adding 0.2 g of luteolin or genistein. Luteolin also increased yellow pigment content by 1.2-fold. Ultra HPLC coupled to quadrupole time-of-flight mass spectrometry was used for the preliminary analysis of Monascus fermentation products. It was found that the amino acid types in RMD are similar to those in yams, but there are fewer polysaccharides and fatty acids.

CONCLUSION

The results obtained in the present study showed that the addition of genistein or luteolin could reduce citrinin on the premise of increasing pigment yield, which laid a foundation for the better use of yams in Monascus fermentation. © 2023 Society of Chemical Industry.

Sampling of cereals and cereal-based foods for the determination of ochratoxin A: an overview

The mycotoxin ochratoxin A (OTA) is known to be heterogeneously distributed both intrinsically (from one individual food item to the next) as well as distributionally (throughout a sample of individual food items) in cereals and cereal-based foods. Therefore, proper sampling and sample comminution are special challenges, but are prerequisites for obtaining sound analytical data. This paper outlines the issue of the sampling process for cereals and cereal-based foods, starting with the planning phase, followed by the sampling step itself and the formation of analytical samples. The sampling of whole grain and retail-level cereal-based foods will be discussed. Furthermore, possibilities to reduce sampling variance are presented.

Occurrence of ochratoxin A and citrinin in Czech cereals and comparison of two HPLC methods for ochratoxin A detection

The aims of the study were to obtain information about the occurrence of ochratoxin A (OTA) and citrinin (CIT) in cereals harvested in the Czech Republic and to compare two analytical procedures for detecting OTA. A total of 34 cereal samples, including two matrix reference materials (R-Biopharm, Germany), were analysed. The results were compared with the limit for raw cereal grains used as a foodstuff according to Commission Regulation No. 1881/2006, which allows a maximum OTA level of 5 µg kg(-1). Compared were two methods based on the high-performance liquid chromatography principle, one using the immunoaffinity columns OchraTest (VICAM) and the second based on solvent partition (PART), both followed by fluorescence detection. The highest OTA contents were found in two barley samples. According to the method employed, the results for the first sample (malting barley) were VICAM = 31.43 µg kg(-1) and PART = 44.74 µg kg(-1). For the second sample (feeding barley) they were VICAM = 48.63 µg kg(-1) and PART = 34.40 µg kg(-1). Two samples of bread wheat had an OTA content approaching the legal limit (VICAM = 4.71 µg kg(-1) and PART = 6.03 µg kg(-1); VICAM = 4.12 µg kg(-1) and PART = 3.95 µg kg(-1)). CIT was analysed using the PART method only, and its highest content (93.64 µg kg(-1)) was found for the malting barley sample with high OTA content (44.74 µg kg(-1) as analysed using PART).

Survey of dry pasta for ochratoxin A in Canada

Ochratoxin A (OTA) was determined in 274 samples of dry pasta sold across Canada in 2004 to 2006. Ground sample was extracted with acetonitrile-water (6:4 [vol/vol]), filtered, diluted with phosphate-buffered saline, and cleaned with an immunoaffinity column. Analysis was by reversed-phase liquid chromatography with fluorescence detection, and in the second year by liquid chromatography-electrospray tandem mass spectrometry as well. For 2004 and 2005, the limit of quantitation was approximately 0.5 ng of OTA per g (signal-to-noise ratio of 10:1). In 2006, the limit of quantitation was estimated to be 0.2 ng of OTA per g. Incidence of contamination above 0.5 ng of OTA per g was 21, 18, and 66% in the years 2004, 2005, and 2006, respectively, reflecting the contamination variability of durum wheat crops and showing the importance of multiyear surveillance. Mean levels of OTA found in these 3 years were, respectively, 0.30, 0.28, and 0.76 ng/g, and maximum levels were, respectively, 1.8, 1.4, and 3.3 ng/g.

Ochratoxin A: The Continuing Enigma

The mycotoxin ochratoxin A (OTA) has been linked to the genesis of several disease states in both animals and humans. It has been described as nephrotoxic, carcinogenic, teratogenic, immunotoxic, and hepatotoxic in laboratory and domestic animals, as well as being thought to be the probable causal agent in the development of nephropathies (Balkan Endemic Nephropathy, BEN and Chronic Interstitial Nephropathy, CIN) and urothelial tumors in humans. As a result, several international agencies are currently attempting to define safe legal limits for OTA concentration in foodstuffs (e.g., grain, meat, wine, and coffee), in processed foods, and in animal fodder. In order to achieve this goal, an accurate risk assessment of OTA toxicity including mechanistic and epidemiological studies must be carried out. Ochratoxin has been suggested by various researchers to mediate its toxic effects via induction of apoptosis, disruption of mitochondrial respiration and/or the cytoskeleton, or, indeed, via the generation of DNA adducts. Thus, it is still unclear if the predominant mechanism is of a genotoxic or an epigenetic nature. One aspect that is clear, however, is that the toxicity of OTA is subject to and characterized by large species- and sex-specific differences, as well as an apparently strict structure-activity relationship. These considerations could be crucial in the investigation of OTA-mediated toxicity. Furthermore, the use of appropriate in vivo and in vitro model systems appears to be vital in the generation of relevant experimental data. The intention of this review is to collate and discuss the currently available data on OTA-mediated toxicity with particular focus on their relevance for the in vivo situation, and also to suggest possible future strategies for unlocking the secrets of ochratoxin A.

Effect of gamma-irradiation on aflatoxin B1 production by Aspergillus flavus and chemical composition of three crop seeds

The effect of gamma-irradiation on aflatoxin B1 production by Aspergillus flavus, and the chemical composition of some different crop seeds were investigated. A. flavus infected seeds behaved differently according to their principal constituents. A. flavus caused an increase in protein and decrease in lipids and carbohydrate contents of wheat, soyabean and fababean seeds. Growth of A. flavus and production of aflatoxin B1 was inhibited at a dose level of 5 kGy. A. flavus utilizes carbohydrates of seeds for its growth and aflatoxin production. Crops were arranged, in descending order, according to aflatoxin produced in seeds as wheat > soyabean > fababean. There were no changes in chemical constituents of irradiated seeds, such as protein, lipids, and carbohydrates.

IgE-reactive proteins from Stachybotrys chartarum

BACKGROUND

Stachybotrys chartarum has been associated with idiopathic pulmonary hemorrhage in infants. This is thought to be mycotoxin-related. There are increasing numbers of reports linking this fungus to the indoor environment of patients with other pulmonary problems, including allergies and asthma.

OBJECTIVE

Given the potential significance of this fungus as a pulmonary pathogen, this work evaluates the antigenic proteins of S. chartarum as to their molecular size and the prevalence of immunoglobulin (Ig)E and IgG directed against them in the general population.

METHODS

S. chartarum was isolated from a local home. S. chartarum for extract production was grown on minimum salts and glucose. Plasma from 132 healthy individuals was evaluated for IgE and IgG directed against S. chartarum using direct and inhibition enzyme immunoassay. The number and molecular size of those proteins that were bound by IgE from pooled sera known to contain IgE to S. chartarum were determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis immunoblotting.

RESULTS

Enzyme immunoassay indicated 65 of 132 (49.2%) sera tested contained IgG against S. chartarum and 13 of 139 (9.4%) sera tested contained IgE against S. chartarum. Pooled sera identified two IgE-binding proteins from extracts of S. chartarum spores and mycelia. These proteins are 34 and 52 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis immunoblot.

CONCLUSIONS

We conclude sensitivity to S. chartarum is potentially much more widespread than previously appreciated. This fungus may impact the asthmatic and allergic population through both immunologic and toxic mechanisms. Its significance in the milieu of allergenic fungi may need to be re-evaluated.

On ochratoxin A and fungal flora in Polish cereals from conventional and ecological farms - Part 1: occurrence of ochratoxin A and fungi in cereals in 1997

Over 200 samples of Polish cereal grain from the 1997 harvest obtained from conventional and ecological farms were tested for the presence of ochratoxin A as well as for contamination by microscopic fungi. Ochratoxin A contamination of rye from ecological farms was over six times more frequent than that from conventional cultivation. The ochratoxin A content in wheat and barley samples from ecological farms was also higher. No wheat sample from conventional farms contained the mycotoxin. In the group of ecological farms, there were differences in the percentage of cereal samples containing ochratoxin A. The ochratoxin A levels ranged from 0.2 to 57 microg kg(-1). The mean concentration of ochratoxin A in investigated cereal grain was 5.7 microg kg(-1). From samples containing detectable amounts of ochratoxin A, fungi producing ochratoxin A under laboratory conditions were isolated. They were classified as belonging to the species Penicillium cyclopium, P. viridicatum, P. chrysogenum and also Aspergillus alliaceus, A. versicolor, A. glaucus and A. flavus. Penicillium strains - producers of ochratoxin A - were isolated from 93% of the samples; in 7% of samples, only Aspergillus strains producing this mycotoxin were noted. Rye samples mainly from one farm with an ecological type of cultivation and from one conventional farm were contaminated with both Aspergillus and Penicillium mycotoxigenic strains.

Deoxynivalenol and ochratoxin A in German wheat and changes of level in relation to storage parameters

The occurrence of the mycotoxins deoxynivalenol (DON) and ochratoxin A (OTA) in the winter wheat of 1997 and 1998 grown under organic farming conditions was investigated using ELISAs (R-Biopharm) for quantification. The influence of delayed drying of the grain after harvest on the development of DON and OTA was determined in storage trials (moisture: 17% and 20%; temperature: 20 degrees C; duration: four and six weeks). The Tox5 PCR assay was used both to detect Fusarium species with the potential to produce trichothecenes and as a measure of their relative DNA content during the storage trials. The intensity of the PCR signals was correlated with the DON concentration. Fusarium species were identified microscopically by standard methods. All the freshly harvested grain samples were contaminated with DON and showed further increases in the DON concentration during storage. OTA contamination was found in 14.3% of the 1997 samples and in 24.1% of the 1998 samples. OTA increased during storage trials of the 1997 samples but not in the 1998 samples.

Influence of water activity on Penicillium citrinum growth and kinetics of citrinin accumulation in wheat

The influence of water activity (aw) on both Penicillium citrinum growth and citrinin accumulation in wheat was studied. Wheat conditioned at different levels of aw and inoculated with a citrinin producer strain was incubated at 30 degrees C for 2 months. Fungal growth was assessed by microscopic examination. P. citrinum grew down to aw 0.775. Citrinin was not detected in the substrate at aw 0.800 and lower. As aw increased the toxin was detected earlier and the maximum accumulation increased markedly (65 microg/kg at aw 0.810, 460 microg/kg at aw 0.825 and 22 mg/kg at aw 0.885). Citrinin concentration declines rapidly after reaching the maximum at each aw level.

Effect of gamma-irradiation on the natural occurrence of Fusarium mycotoxins in wheat, flour and bread

A survey was carried out to obtain data on the occurrence of Fusarium mycotoxin in wheat and flour samples collected from local markets in Egypt and to study the influence of gamma-irradiation on controlling the occurrence of these mycotoxins in wheat, flour and bread. Deoxynivalenol (DON) was detected in five samples of wheat at levels ranging from 103 to 287 micrograms/kg and one sample each of flour and bread at concentrations 188 and 179 micrograms/kg. Zearalenone (ZEN) was detected in ten samples of wheat at levels from 28 to 42 micrograms/kg and four samples each of flour and bread at concentrations of 95 and 34 micrograms/kg, respectively. T-2 toxin was detected only in one sample each of wheat, flour and bread at concentrations of 2.9, 2.2 and 2.3 micrograms/kg, respectively. Gamma-irradiation at dose level of 6 kGy completely eliminated fungal flora in flour and wheat. DON, ZEN and T-2 toxin concentrations are reduced to 85, 20 and 2.0 micrograms/kg for wheat and to 125, 45 and 1.0 micrograms/kg for flour after 4 kGy exposure and a sharp drop in Fusarium toxin levels occurred at 6 kGy and as eliminated at 8 kGy. Bread prepared from 6 kGy was contaminated with Fusarium toxin at levels below 5 microgram/kg. It was noticed that gamma-irradiation reduce greatly the natural occurrence of Fusarium mycotoxins in bread.

Citrinin

Citrinin, a nephrotoxic mycotoxin, has been of growing importance also for the "International Agency for Research on Cancer", ever since its presumable role in the occurrence of Balcan endemic nephropathy (BEN) was discussed at the congress on "Mycotoxins, Endemic Nepthropathy and Urinary Tract Tumours" held in Lyon in June 1991 (12). In late 1991, citrinin was therefore also included in the list of toxins to be examined by the screening subcommittees on natural toxins of the International Live Science Institute, European Branch.

Mycotoxin formation in HY-320 wheat during granary storage at 15 and 19% moisture content

Eleven-kilogram parcels of HY-320 wheat, a cultivar of the new Canada Prairie Spring class, were kept at 15 and 19% initial moisture contents (IMC) in simulated storage in a Manitoba farm granary for 60 weeks to determine biotic and abiotic changes and mycotoxin production. Ochratoxin A reached a maximum of 0.24 ppm by week 20 in the 19% IMC wheat, but was absent in the 15% IMC wheat; no other mycotoxins were detected. Temperature, moisture content, O2 and CO2 levels, fat acidity values, seed germination, microfloral incidence and abundance, and the presence of other mycotoxins were monitored. Principal component analysis of all variables showed that the first principal components accounted for 32-41% of the system variability, and contained the ochratoxin A variable. Ochratoxin A was produced in moist grain that had decreased seed germination and Alternaria activity, and high fungal activity by Penicillium and Aspergillus versicolor. Compared to other stored cereals previously studied, HY-320 wheat would be ranked in a low-risk category for mycotoxin formation, based on the ochratoxin A levels observed.