Ochratoxin A decontamination: A review

Occurrence of ochratoxin A in typical salami produced in different regions of Italy

A total of 172 different salamis were purchased from farms and small salami factories located in four Italian regions (Piedmont, Veneto, Calabria, and Sicily) and analyzed for the presence of ochratoxin A (OTA). Analysis was performed by high-performance liquid chromatography coupled to a fluorimetric detector (HPLC-FLD). The detection limit (LOD) for the method used was 0.05 μg/kg, while the quantitation limit (LOQ) was 0.20 μg/kg; the average recovery rate was 89.1%. OTA was detected in 22 salamis, and 3 samples exceeded the Italian guidance value for OTA in pork meat (1 μg/kg). In particular, what emerges from this research is the high percentage of spicy salamis among positive samples (68.2%, 15 out of 22), although spicy salamis are only 27.3% of the total number of samples collected and analyzed. Red chili pepper contaminated by OTA could be responsible for the presence of the mycotoxin in these spicy salamis. It follow that, also the control of some ingredients used in the manufacture of these meat products, like spices, should not be neglected.

The Multiple and Versatile Roles of Aureobasidium pullulans in the Vitivinicultural Sector

The saprophytic yeast-like fungus Aureobasidium pullulans has been well documented for over 60 years in the microbiological literature. It is ubiquitous in distribution, being found in a variety of environments (plant surfaces, soil, water, rock surfaces and manmade surfaces), and with a worldwide distribution from cold to warm climates and wet/humid regions to arid ones. Isolates and strains of A. pullulans produce a wide range of natural products well documented in the international literature and which have been regarded as safe for biotechnological and environmental applications. Showing antagonistic activity against plant pathogens (especially post-harvest pathogens) is one of the major applications currently in agriculture of the fungus, with nutrient and space competition, production of volatile organic compounds, and production of hydrolytic enzymes and antimicrobial compounds (antibacterial and antifungal). The fungus also shows a positive role on mycotoxin biocontrol through various modes, with the most striking being that of binding and/or absorption. A. pullulans strains have been reported to produce very useful industrial enzymes, such as β-glucosidase, amylases, cellulases, lipases, proteases, xylanases and mannanases. Pullulan (poly-α-1,6-maltotriose biopolymer) is an A. pullulans trademark product with significant properties and biotechnological applications in the food, cosmetic and pharmaceutical industries. Poly (β-l-malic acid), or PMA, which is a natural biopolyester, and liamocins, a group of produced heavy oils and siderophores, are among other valuable compounds detected that are of possible biotechnological use. The fungus also shows a potential single-cell protein source capacity with high levels of nucleic acid components and essential amino acids, but this remains to be further explored. Last but not least, the fungus has shown very good biocontrol against aerial plant pathogens. All these properties are of major interest in the vitivinicultural sector and are thoroughly reviewed under this prism, concluding on the importance that A. pullulans may have if used at both vineyard and winery levels. This extensive array of properties provides excellent tools for the viticulturist/farmer as well as for the oenologist to combat problems in the field and create a high-quality wine.

A fluorometric aptamer-based assay for ochratoxin A using magnetic separation and a cationic conjugated fluorescent polymer

A fluorometric aptamer-based assay for ochratoxin A (OTA) is described. It is making use of magnetic separation and a cationic conjugated fluorescent polymer. Amino-tagged aptamer (Apt) against OTA is immobilized on magnetic beads (MBs) to form a conjugate of type Apt-MBs. The immobilized aptamer is partially complementary to carboxyfluorescein-labeled DNA which binds to the Apt-MBs via hybridization if OTA is absent. Only few FAM-DNA will remain in the supernatant after magnetic separation, and only weak fluorescence resonance energy transfer (FRET) occurs on addition of the fluorescent polymer. If, however, OTA is present, it will bind to the aptamer and prevent the hybridization between Apt-DNA and FAM-DNA. This results in the presence of large amounts of FAM-DNA in the supernatant after magnetic separation. On addition of fluorescent polymer, efficient FRET occurs from the polymer to FAM-DNA. Fluorescence, best measured at excitation/emission peaks of 370/530 nm, increases with increasing concentrations of OTA. This assay is highly sensitive and selective. The detection limit is as low as 0.11 ng mL^-1. This is 6 times lower than the aptamer assay without using the fluorescent polymer. Conceivably, this method has a wider scope in that it may be extended to other mycotoxins by simply changing the aptamer. Graphical Abstract Schematic of a fluorometric aptamer assay for ochratoxin A (OTA). It is based on magnetic separation coupled with a cationic conjugated polymer (PFP).

Determination of Ochratoxin A traces in foodstuffs: Comparison of an automated on-line two-dimensional high-performance liquid chromatography and off-line immunoaffinity-high-performance liquid chromatography system

Automated on-line two-dimensional high-performance liquid chromatography method (2D-HPLC) is proposed to determine Ochratoxin A (OTA) in food samples as an alternative to OTA immunoaffinity column (IAC). An on-line 2D-HPLC system is designed for the analysis of OTA using an affinity-based monolithic column in the first dimension and reversed-phase C18 column in the second dimension. Initially, optimal OTA separation efficiency is determined through traditional HPLC system consisting of a P(HEMAPA) monolithic column coupled with HPLC system. Secondly, after providing optimum conditions, OTA determination was investigated through the 2D-HPLC system. According to results, 2D-HPLC system showed good linearity in the range 0.5 to 20 ng/mL with limit of detection (LOD) and limit of quantification (LOQ) values of 21.2 pg/mL and 64.3 pg/mL, respectively. The P(HEMAPA)-4 monolithic column displayed good recovery of OTA ranging from 104.34% to 107.33%. Relative standard deviations (RSD) varied in the range 0.21% to 1.31% thus indicating the efficiency of P(HEMAPA)-4 monolithic column developed for OTA.

Exonuclease-assisted multicolor aptasensor for visual detection of ochratoxin A based on G-quadruplex-hemin DNAzyme-mediated etching of gold nanorod

An exonuclease-assisted multicolor aptasensor was developed for the visual detection of ochratoxin A (OTA). It is based on the etching of gold nanorods (AuNRs) mediated by a G-quadruplex-hemin DNAzyme. A DNA sequence (AG4-OTA) was designed that comprises a hemin aptamer and an OTA aptamer. OTA binds to AG4-OTA to form an antiparallel G-quadruplex, which halts its digestion by exonuclease I (Exo I) from the 3'-end of AG4-OTA. Thus, the retained hemin aptamer can bind to hemin to form a G-quadruplex-hemin DNAzyme. This DNAzyme has peroxidase-like activity that catalyzes the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by H₂O₂ to produce its diimine derivative (TMB²⁺) in acidic solution. TMB²⁺ can etch the AuNRs by oxidizing Au(0) into Au(I). This results in the generation of rainbow-like colors and provides a multicolor platform for the visual detection of OTA. The assay is based on the use of a single isolated aptamer and possesses obvious advantages such as multi-color visual inspection, relatively high sensitivity and accuracy. It can be used to detect as little as 30 nM concentrations of OTA by visual observation and even 10 nM concentrations by spectrophotometry. The method was successfully applied to the determination of OTA in spiked beer where it gave recoveries of 101-108%, with a relative standard deviation (RSD, n = 5) of <5%. Graphical abstract Schematic of an exonuclease-assisted multicolor bioassay based on the G-quadruplex-hemin DNAzyme-mediated etching of gold nanorods (AuNRs). It enables visual detection of ochratoxin A (OTA) with a detection limit of 30 nM.

Isolation of Aflatoxin B1 from Moldy Foods by Solid-Phase Extraction Combined with Bifunctional Ionic Liquid-Based Silicas

A solid-phase extraction method was developed by using new bifunctional ionic liquid-based silicas as sorbents to isolate aflatoxin B1 from moldy corn and peanut. Firstly, according to the adsorption efficiency, two sorbents imidazolium chloride-butylimidazolium chloride-based silica (Sil@BIm-Im) and imidazolium chloride-hexylimidazolium chloride-based silica (Sil@HIm-Im) were selected. The RSM was introduced to optimize adsorption conditions such as methanol/water ratio, time, and pH. Sil@HIm-Im, which had the highest adsorption efficiency, was used in SPE as a sorbent. After 2.0 mL of loading samples, washing solvents were optimized as 6.0 mL and 4.0 mL of water for corn and peanut, 2.0 mL of acetonitrile, and 3.0 mL of methanol. 3.0 mL of methanol/acetic acid (2.0% vol.) was investigated as an elution solvent. Finally, 0.009 μg/g and 0.023 μg/g of aflatoxin B1 were obtained in corn and peanut extract with recoveries of 80.0%-103.3% and RSDs of 2.37%-6.58%.

Predominant mycotoxins, mycotoxigenic fungi and climate change related to wine

Wine is a significant contributor to the economies of many countries. However, the commodity can become contaminated with mycotoxins produced by certain fungi. Most information on mycotoxins in wine is from Spain, Italy and France. Grapes can be infected by mycotoxigenic fungi, of which Aspergillus carbonarius producing ochratoxin A (OTA) is of highest concern. Climate is the most important factor in determining contamination once the fungi are established, with high temperatures being a major factor for OTA contamination: OTA in wine is at higher concentrations in warmer southern Europe than northern. Contamination by fumonisins is a particular concern, related to Aspergillus niger producing these compounds and the fungus being isolated frequently from grapes. Aflatoxins can be present in wine, but patulin is seldom detected. Alternaria mycotoxins (e.g. alternariol) have been frequently observed. There are indications that T-2 toxin may be common. Also, the combined effects of mycotoxins in wine require consideration. No other mycotoxins are currently of concern. Accurate fungal identifications and mycotoxin detection from the fungi are important and a consideration of practical methods are required. There is a diversity of wines that can be contaminated (e.g. red, white, sweet, dry and fortified). The occurrence of OTA is higher in red and sweet than white wines. Steps to control mycotoxins in wine involve good agriculture practices. The effect of climate change on vines and mycotoxins in wine needs urgent consideration by well-constructed modelling studies and expert interpretation of existing data. Reliable models of the effect of climate change on vines is a priority: the health of vines affects mycotoxin contamination. A modelling study of OTA in grapes at higher temperatures over 100years is required. Progress has been made in reducing OTA in wine. The other mycotoxins require consideration and the effects of climate change will become crucial.

Raisins and Currants as Conventional Nutraceuticals in Italian Market: Natural Occurrence of Ochratoxin A

The healthy consumers make a strong pressure to natural products that can prevent the chronic diseases and improve the general health status, and therefore an important aspect that have to be considered is the safe level of the nutraceuticals. This study reports the occurrence of Ochratoxin A (OTA) and associated fungal contamination in 35 samples of dried vine fruits imported in the European community potentially used for the development of new nutraceutical supplements. High pressure liquid chromatography analysis identified 18 samples as contaminated by OTA with an average level of 2.6 μg/kg. OTA was measured in 4 samples of currants (mean value of 6.6 μg/kg) and 13 samples of raisins (mean value of 1.4 μg/kg). In one sample of currants and one of raisins from Turkey OTA exceeded the limits set by European Commission of 10 μg/kg, being contaminated with 12.61 and 15.99 μg/kg, respectively. All the positive samples were confirmed by Orbitrap Q Exactive through their molecular weight and the corresponding fragmentation. The worldwide consumption of dried vine fruits contributed to OTA exposure in several group of consumers. In particular, considering the potential nutraceutical approach, this consumption may be represent a severe risk for healthy consumers that consider these products like healthy and salutistic for their contents in antioxidants, flavonoids, and polyphenols. Data reported in this study confirmed the need to regularly monitor mycotoxin levels in these food products and optimize the process of fruits drying in order to reduce the development of toxigenic molds.

Gamma irradiation effects on ochratoxin A: Degradation, cytotoxicity and application in food

Ochratoxin A (OTA) is one of the main mycotoxins that can be found in food. The use of gamma radiation is a technique for preserving food that may exert some effects on mycotoxins. OTA was irradiated in its dry form, in aqueous and in methanolic solutions, and in wheat flour, grape juice and wine. Additionally, the toxicity of OTA irradiated in water was tested. In aqueous solutions, more than 90% of the OTA was degraded by γ-radiation doses ≥2.5kGy, and a 2-fold reduction in OTA cytotoxicity was observed. In food matrices, the elimination of OTA by γ-radiation was found more difficult, as radiation doses of 30kGy eliminate at most 24% of the OTA. Higher moisture content of food matrices did not substantially increase OTA elimination. It is concluded that OTA is very sensitive to irradiation in water solutions but resistant in its dry form and in food matrices.

Electrochemical aptasensors for contaminants detection in food and environment: Recent advances

The growing number of contaminants requires the development of new analytical tools to meet the increasing demand for legislative actions on food safety and environmental pollution control. In this context, electrochemical aptamer-based sensors appear promising among all biosensors because they permit multiplexed analysis and provide fast response, sensitivity, specificity and low cost. The aim of this review is to give the readers an overview of recent important achievements in the development of electrochemical aptamer-based biosensors for contaminant detection over the last two years. Special emphasis is placed on aptasensors based on screen-printed electrodes which show a substantial improvement of analytical performances.

Hydrogel Based Biosensors for In Vitro Diagnostics of Biochemicals, Proteins, and Genes

Hydrogel-based biosensors have drawn considerable attention due to their various advantages over conventional detection systems. Recent studies have shown that hydrogel biosensors can be excellent alternative systems to detect a wide range of biomolecules, including small biochemicals, pathogenic proteins, and disease specific genes. Due to the excellent physical properties of hydrogels such as the high water content and stimuli-responsive behavior of cross-linked network structures, this system can offer substantial improvement for the design of novel detection systems for various diagnostic applications. The other main advantage of hydrogels is the role of biomimetic three-dimensional (3D) matrix immobilizing enzymes and aptamers within the detection systems, which enhances their stability. This provides ideal reaction conditions for enzymes and aptamers to interact with substrates within the aqueous environment of the hydrogel. In this review, we have highlighted various novel detection approaches utilizing the outstanding properties of the hydrogel. This review summarizes the recent progress of hydrogel-based biosensors and discusses their future perspectives and clinical limitations to overcome.

Ochratoxin A: Molecular Interactions, Mechanisms of Toxicity and Prevention at the Molecular Level

Ochratoxin A (OTA) is a widely-spread mycotoxin all over the world causing major health risks. The focus of the present review is on the molecular and cellular interactions of OTA. In order to get better insight into the mechanism of its toxicity and on the several attempts made for prevention or attenuation of its toxic action, a detailed description is given on chemistry and toxicokinetics of this mycotoxin. The mode of action of OTA is not clearly understood yet, and seems to be very complex. Inhibition of protein synthesis and energy production, induction of oxidative stress, DNA adduct formation, as well as apoptosis/necrosis and cell cycle arrest are possibly involved in its toxic action. Since OTA binds very strongly to human and animal albumin, a major emphasis is done regarding OTA-albumin interaction. Displacement of OTA from albumin by drugs and by natural flavonoids are discussed in detail, hypothesizing their potentially beneficial effect in order to prevent or attenuate the OTA-induced toxic consequences.

Comparison of ochratoxin A levels in edible pig tissues and in biological fluids after exposure to a contaminated diet

The aim of this study was to compare ochratoxin A (OTA) levels in pig tissues and biological fluids after animal exposure to contaminated diet (250 μg OTA/kg of feed) during 4 weeks of fattening. OTA concentrations were quantified using a validated immunoassay method (ELISA) and high-performance liquid chromatography with fluorescence detector (HPLC-FD). The highest mean OTA concentration in pig tissues was determined in kidneys of exposed animals (13.87 ± 1.41 μg/kg), followed by lungs (10.47 ± 1.97 μg/kg), liver (7.28 ± 1.75 μg/kg), spleen (4.81 ± 0.99 μg/kg), muscle tissue (4.72 ± 0.86 μg/kg), fat tissue (4.11 ± 0.88 μg/kg), heart (3.71 ± 1.09 μg/kg), and brain (3.01 ± 0.25 μg/kg). Furthermore, on the last day of exposure (day 28), significantly higher mean OTA levels were determined in urine (16.06 ± 3.09 μg/L) in comparison to serum (4.77 ± 1.57 μg/L) showing that OTA urine analysis could be a good marker to identify elevated levels of this contaminant in porcine tissues used for human consumption. This study gave guidelines for the most efficient OTA control in pig-derived biological materials that can be exercised at slaughterhouses.

Assessment of ochratoxin A stability following gamma irradiation: experimental approaches for feed detoxification perspectives

The present study evaluated the effect of gamma irradiation on the stability of ochratoxin A (OTA) under various conditions. The effects of the physical state of OTA (solid vs aqueous), initial OTA concentration, irradiation dose and dose rate as well as the presence of model substances simulating food matrix compounds on OTA radiostability were investigated. First, pure OTA with and without food model compounds including α-D-glucose (monosaccharide), Methyl α-D-glucopyranoside (starch) and the amino acid derivatives N-α-acetyl-L-lysine methyl ester and N-α-acetyl-L-cysteine methyl ester (protein models) were irradiated with doses of 2, 4 and 8 kGy applied at 15.117 and 108.24 Gy/min. Secondly, artificially OTA-contaminated wheat with different moisture content (11, 14 and 16%) was irradiated with doses of 2, 4 and 8 kGy applied at 63.39 Gy/min. Residual OTA levels were analysed using ultra-high performance liquid chromatography coupled with tandem mass spectrometry. Solid OTA (50 and 3,200 ng/ml)showed great irradiation stability, even with irradiation doses up to 8 kGy. Under dry conditions, the presence of food model components did not affect OTA radiostability. However, in an aqueous solution, complete reduction was achieved at the initial OTA concentration of 50 ng/ml and irradiation dose of 2 kGy. Applying gamma irradiation to cereal-based food model systems produced a significant OTA reduction (5,000 µg/kg) of 47.2% in moistened wheat kernels (16%) with an absorbed dose of 8 kGy but failed to reduce the OTA content of low moisture content wheat (11%). These model experiments offered a useful tool to assess the main key factors affecting gamma irradiation-induced OTA reduction. Gamma irradiation is promising since the irradiation doses applied could partially reduce OTA contamination. Nevertheless, its efficacy was largely affected by initial moisture content and could be dangerous if toxic by-products are produced or nutritive quality is lost and needs further study.

Ochratoxin A is degraded by Yarrowia lipolytica and generates non-toxic degradation products

The mycotoxin ochratoxin A (OTA) is a common contaminant of various plant-derived foods and feeds. However, methods for complete decontamination remain to be established. Recently, biological approaches for mycotoxin removal using various species of yeast have been explored. In the present study, we investigated the efficacy of OTA degradation by the yeast Yarrowia lipolytica under various conditions, altering yeast concentration, temperature, pH, and concentration of OTA in order to determine the optimal requirements of this species. At a yeast concentration of 108 cells/ml, the degradation rate was higher than that observed at any other concentration and, after 24 h, the OTA concentration was reduced to almost half of the initial level introduced to the culture. Further, Y. lipolytica cultured at 28 °C showed the highest level of OTA degradation. Similarly, the culture performed optimally at a pH of 4. The initial concentration of OTA also affected the ability of the yeast to degrade OTA, with the level of degradation being the highest when the initial OTA concentration was 0.1 μg/ml. Moreover, we also tested the toxicity of the OTA biodegradation products using HepG2 cells to determine the physiological applicability of this yeast species in the food industry and observed that these products were notably less toxic than non-degraded OTA. Y. lipolytica effectively reduced natural decay incidence of grapes, and had no negative effect to the storage quality of grape fruits. Taken together, these data suggest that Y. lipolytica could be a viable OTA contamination prevention/treatment option and additional research concerning its commercial use is warranted.

Biodegradation of Ochratoxin A by Bacterial Strains Isolated from Vineyard Soils

Ochratoxin A (OTA) is a mycotoxin with a main nephrotoxic activity contaminating several foodstuffs. In the present report, five soil samples collected from OTA-contaminated vineyards were screened to isolate microorganisms able to biodegrade OTA. When cultivated in OTA-supplemented medium, OTA was converted in OTα by 225 bacterial isolates. To reveal clonal relationships between isolates, molecular typing by using an automated rep-PCR system was carried out, thus showing the presence of 27 different strains (rep-PCR profiles). The 16S-rRNA gene sequence analysis of an isolate representative of each rep-PCR profiles indicated that they belonged to five bacterial genera, namely Pseudomonas, Leclercia, Pantoea, Enterobacter, and Acinetobacter. However, further evaluation of OTA-degrading activity by the 27 strains revealed that only Acinetobacter calcoaceticus strain 396.1 and Acinetobacter sp. strain neg1, consistently conserved the above property; their further characterization showed that they were able to convert 82% and 91% OTA into OTα in six days at 24 °C, respectively. The presence of OTα, as the unique OTA-degradation product was confirmed by LC-HRMS. This is the first report on OTA biodegradation by bacterial strains isolated from agricultural soils and carried out under aerobic conditions and moderate temperatures. These microorganisms might be used to detoxify OTA-contaminated feed and could be a new source of gene(s) for the development of a novel enzymatic detoxification system.

Adsorption of ochratoxin A from grape juice by yeast cells immobilised in calcium alginate beads

Grape juice can be easily contaminated with ochratoxin A (OTA), one of the known mycotoxins with the greatest public health significance. Among the different approaches to decontaminate juice from this mycotoxin, microbiological methods proved efficient, inexpensive and safe, particularly the use of yeast or yeast products. To ascertain whether immobilisation of the yeast biomass would lead to successful decontamination, alginate beads encapsulating Candida intermedia yeast cells were used in our experiments to evaluate their OTA-biosorption efficacy. Magnetic calcium alginate beads were also prepared by adding magnetite in the formulation to allow fast removal from the aqueous solution with a magnet. Calcium alginate beads were added to commercial grape juice spiked with 20 μg/kg OTA and after 48 h of incubation a significant reduction (>80%), of the total OTA content was achieved, while in the subsequent phases (72-120 h) OTA was slowly released into the grape juice by alginate beads. Biosorption properties of alginate-yeast beads were tested in a prototype bioreactor consisting in a glass chromatography column packed with beads, where juice amended with OTA was slowly flowed downstream. The adoption of an interconnected scaled-up bioreactor as an efficient and safe tool to remove traces of OTA from liquid matrices is discussed.

Sensitive quantitation of Ochratoxin A in cocoa beans using differential pulse voltammetry based aptasensor

In this work, we propose for the first time a sensitive Ochratoxin A (OTA) detection in cocoa beans using competitive aptasensor by differential pulse voltammetry (DPV). In the proposed method, biotin labeled and free OTA competed to bind with immobilized aptamer onto the surface of a screen printed carbon electrode (SPCE), and percentage binding was calculated. The detection was performed after adding avidin-ALP to perform avidin-biotin reaction; the signal was generated through a suitable substrate 1-naphthyl phosphate (1-NP), for alkaline phosphatase (ALP). The cocoa samples were extracted and purified using molecular imprinted polymer (MIP) columns specifically designed for OTA. The developed aptasensor showed a good linearity in the range 0.15-5 ng/mL with the limit of detection (LOD) 0.07 ng/mL and 3.7% relative standard deviation (RSD). The aptasensor displayed good recovery values in the range 82.1-85% with 3.87% RSD, thus, demonstrated the efficiency of proposed aptasensor for such matrices.

Replacing soybean meal for wet brewer's grains or urea on the performance of lactating dairy cows

The purpose of this research was to evaluate the partial replacement of soybean meal (SBM) for wet brewer's grains (WBG) or urea on the performance of lactating dairy cows. The second investigated whether WBG ensiled with corn kept animal performance in low- and high-producing dairy cows compared with WBG. In experiment I, 40 Holstein cows were used in 4 × 4 Latin square design. The treatments comprised WBG or urea as partial replacement for SBM, as follows: control (diet based on SBM and 1 % of urea), 10 % of WBG, 20 % of WBG, and 2 % of urea. Dry matter intake (DMI) was not affected by treatments. WBG increased milk yield linearly, but it decreased with urea. Milk fat content responded quadratically to WBG levels. Milk protein content decreased, while plasma urea nitrogen increased with high urea addition. In experiment II, 42 Holstein cows were divided into two groups according to production levels. Eighteen cows composed the group of low producing, while the high-producing group comprised 24 cows. The experimental design was a crossover with two periods of 14 days. The experimental treatments consisted of feeding WBG or WBG ensiled with ground corn. Regardless of the production level, no difference in milk yield and milk composition between treatments was observed.

Saccharomyces cerevisiae cell wall components as tools for ochratoxin a decontamination

The aim of this study was to evaluate the usefulness of Saccharomyces cerevisiae cell wall preparations in the adsorption of ochratoxin A (OTA). The study involved the use of a brewer’s yeast cell wall devoid of protein substances, glucans obtained by water and alkaline extraction, a glucan commercially available as a dietary supplement for animals and, additionally, dried brewer’s yeast for comparison. Fourier Transform Infrared (FTIR) analysis of the obtained preparations showed bands characteristic for glucans in the resulting spectra. The yeast cell wall preparation, water-extracted glucan and the commercial glucan bound the highest amount of ochratoxin A, above 55% of the initial concentration, and the alkaline-extracted glucan adsorbed the lowest amount of this toxin. It has been shown that adsorption is most effective at a close-to-neutral pH, while being considerably limited in alkaline conditions.

The adsorption of ochratoxin a by lactobacillus species

The objective of this study was to examine ochratoxin A (OTA) binding by three lactic acid bacteria (LAB) species: Lactobacillus plantarum, L. brevis, and L. sanfranciscensis. Experiments were conducted using MRS medium and PBS buffer contaminated with 1000 ng/mL OTA and inoculated with live or thermally inactivated bacterial biomass at a concentration of 1 or 5 mg dry weight/mL. It was found that, depending on the strain and biomass density, live bacterial cells reduced OTA content by 16.9% to 35% in MRS medium and by 14.8% to 26.4% in PBS after 24 h of contact. OTA binding was higher in the case of thermally inactivated bacterial biomass (46.2% to 59.8%). The process is very rapid: OTA was removed from PBS as early as after 30 min of contact. The binding of the toxin by cells was partially reversible under the treatment by water and 1 M HCl. The results show that OTA is adsorbed to the surface structures of the cell wall, which is promoted not only by the hydrophobic properties of the cell wall, but also by electron donor-acceptor and Lewis acid-base interactions.

Presence of ochratoxin A (OTA) mycotoxin in alcoholic drinks from southern European countries: wine and beer

The main filamentous fungi producers of mycotoxins are Aspergillus spp., Penicillium spp., and Fusarium spp. Their effect can provoke a broad range of toxic properties including carcinogenicity and neurotoxicity, as well as reproductive and developmental toxicities. Ochratoxin A (OTA) is produced by Aspergillus and Penicillium spp. The purpose of this review was to evaluate the risk assessment of OTA in alcoholic drinks (beer and wine) by compiling the results obtained from studies and reviews related to the presence of OTA in these two drinks from southern European countries in the period 2005-2013 and comparing those results with the legislation available in the European Union.

Effects of Storage Duration and Temperature on the Chemical Composition, Microorganism Density, and In vitro Rumen Fermentation of Wet Brewers Grains

This study aimed to investigate the effects of storage duration and temperature on the characteristics of wet brewers grains (WBG) as feeds for ruminant animals. Four storage temperatures (5°C, 15°C, 25°C, and 35°C) and four durations (0, 1, 2, and 3 d) were arranged in a 4×4 factorial design. Surface spoilage, chemical composition and microorganism density were analyzed. An in vitro gas test was also conducted to determine the pH, ammonia-nitrogen and volatile fatty acid (VFA) concentrations after 24 h incubation. Surface spoilage was apparent at higher temperatures such as 25°C and 35°C. Nutrients contents decreased concomitantly with prolonged storage times (p<0.01) and increasing temperatures (p<0.01). The amount of yeast and mold increased (p<0.05) with increasing storage times and temperatures. As storage temperature increased, gas production, in vitro disappearance of organic matter, pH, ammonia nitrogen and total VFA from the WBG in the rumen decreased (p<0.01). Our results indicate that lower storage temperature promotes longer beneficial use period. However, when storage temperature exceeds 35°C, WBG should be used within a day to prevent impairment of rumen fermentation in the subtropics such as Southeast China, where the temperature is typically above 35°C during summer.

Natural occurrence, analysis, and prevention of mycotoxins in fruits and their processed products

Mycotoxins are small toxic chemical products formed as the secondary metabolites by fungi that readily contaminate foods with toxins in the field or after harvest. The presence of mycotoxins, such as aflatoxins, ochratoxin A, and patulin, in fruits and their processed products is of high concern for human health due to their properties to induce severe acute and chronic toxicity at low-dose levels. Currently, a broad range of detection techniques used for practical analysis and detection of a wide spectrum of mycotoxins are available. Many analytical methods have been developed for the determination of each group of these mycotoxins in different food matrices, but new methods are still required to achieve higher sensitivity and address other challenges that are posed by these mycotoxins. Effective technologies are needed to reduce or even eliminate the presence of the mycotoxins in fruits and their processed products. Preventive measures aimed at the inhibition of mycotoxin formation in fruits and their processed products are the most effective approach. Detoxification of mycotoxins by different physical, chemical, and biological methods are less effective and sometimes restricted because of concerns of safety, possible losses in nutritional quality of the treated commodities and cost implications. This article reviewed the available information on the major mycotoxins found in foods and feeds, with an emphasis of fruits and their processed products, and the analytical methods used for their determination. Based on the current knowledge, the major strategies to prevent or even eliminate the presence of the mycotoxins in fruits and their processed products were proposed.

Further aspects of ochratoxin A-cation interactions: complex formation with zinc ions and a novel analytical application of ochratoxin A-magnesium interaction in the HPLC-FLD system

Ochratoxin A (OTA) is a mycotoxin produced by different Aspergillus and Penicillium species. Since its mechanism of action is not fully understood yet, it is important to gain further insight into different interactions of OTA at the molecular level. OTA is found worldwide in many foods and drinks. Moreover, it can also be detected in human and animal tissues and body fluids, as well. Therefore, the development of highly sensitive quantitative methods for the determination of OTA is of utmost importance. OTA most likely forms complexes with divalent cations, both in cells and body fluids. In the present study, the OTA-zinc interaction was investigated and compared to OTA-magnesium complex formation using fluorescence spectroscopy and molecular modeling. Our results show that zinc(II) ion forms a two-fold higher stable complex with OTA than magnesium(II) ion. In addition, based on the enhanced fluorescence emission of OTA in its magnesium-bound form, a novel RP-HPLC-fluorescence detector (FLD) method was also established. Our results highlight that the application of magnesium chloride in alkaline eluents results in an approximately two-fold increase in sensitivity using the HPLC-FLD technique.