Ochratoxin A decontamination: A review

Ochratoxin A (OTA) is a toxic metabolite produced by Aspergillus and Penicillium fungi. As it can contaminate a wide variety of foodstuffs, maximum permitted levels have been established by the EU and other countries. The methods currently employed to prevent OTA contamination in different commodities are reviewed. Pre-harvest strategies are the most efficient. They are aimed to reduce fungal infection by aplying good agricultural practices. During harvest, the use of clean farming equipment, mechanical damage prevention and overripe or fermented fruits discard are convenient practices. In the post-harvest, storage is the most critical phase. Environmental conditions, in particular moisture and temperature, have to be well-controlled in this stage. Detoxificating treatments and products with protecting effects against OTA toxic action are also outlined.     

Mechanical properties of wood of two Mexican oaks: relationship to selected physical properties

The relationship between 27 mechanical parameters and density, shrinkage coefficients, moisture content, anisotropy ratio, and the fiber saturation point (FSP) in small specimens of Quercus crassifolia Humb. & Bonpl. and Q. laurina Humb. & Bonpl. wood, from Oaxaca, Mexico, is described. Wood from both oaks displayed low dimensional stability, while mechanical testing results revealed a strong material in most forms of stress, as well as a high impact-resistance wood. Wood mechanical properties in dry and green state were positively correlated with density, shrinkage coefficients, and FSP. Density was generally the single best predictor for mechanical strength, although the modulus of elasticity was a better predictor of the modulus of rupture in the bending tests. Univariate models to predict mechanical properties using the best regressor of the physical properties gave R² values from 0.104 (p?=?0.015) to 0.494 (p?<?0.001), whereas multivariate regression significantly increased the predictive power of the models, with R² values from 0.190 (p?=?0.004) to 0.646 (p?<?0.001).     

Absorption of sodium diclofenac after ocular administration in rabbit

Sodium diclofenac (DCF, CAS 1507-79-6) is a non-steroidal anti-inflammatory drug whose activity is mainly due to an inhibitory effect on the synthesis of the prostaglandins. At present, a tendency towards its topical use in the treatment of the inflammatory state of the anterior segment of the eye as an alternative to the steroid drugs is observed. The pharmacokinetics of DCF was studied in rabbits by assessing the ocular and systemic absorption of DCF after administering DCF eye drops. The chromatographic methods available were not sensitive enough to quantify the extremely low drug concentrations which appeared in the biological fluids after ocular treatment. For this reason, the concentrations of DCF in plasma and aqueous humor were evaluated by a coupled liquid chromatography/gas chromatography (LC/GC) method. DCF was absorbed well through the cornea with the aqueous humor concentration peak being 757.8 ng/ml at 120 min. This good ocular absorption of DCF was confirmed by the concentrations observed in plasma. The presence of tramazoline (TMZ, CAS 74195-73-6) in the eye drops increases the levels of DCF in aqueous humor.     

Co-occurrence of aflatoxins,ochratoxin A and zearalenone in breakfast cereals from spanish market

Forty-six breakfast cereal samples from the Spanish market have been analyzed for the occurrence of aflatoxins (AFB1, AFG1, AFB2 and AFG2), ochratoxin A (OTA) and zearalenone (ZEA). According to the results, 9% of the samples were contaminated with AFB1 although no sample exceeded the LOQ (0.2 μg kg^?1), and no sample presented detectable levels of the other aflatoxins (AFB2, AFG1 and AFG2). Zearalenone and OTA contaminated 48 and 39% of the samples, respectively, with mean values of the samples having quantification levels of 25.40 and 0.37 μg kg^?1, respectively. The co-occurrence of OTA and ZEA was observed in 28% of the samples. Aflatoxin B1 appeared only in the corn-based breakfast cereals, whereas ZEA and OTA showed the highest contamination rates in the samples containing wheat and wheat and rice, respectively. No sample of high-fiber content was contaminated with AFB1, whereas OTA and ZEA occurred with higher incidence in high-fiber content samples. Moreover, the daily exposure to AFB1, OTA and ZEA is discussed.     

Short communication: Analysis of mycotoxins in Spanish milk

We surveyed the presence of 22 mycotoxins in 191 Spanish cow milk samples. Mycotoxins could be carried over from diet into animal milk and have toxic effects on human and animal health. The interaction of different mycotoxins may be additive or synergetic. Therefore, surveillance of mycotoxin co-occurrence in milk is recommended. Aflatoxins M₁, B₁, B₂, G₁, and G₂, ochratoxins A and B, nivalenol, deoxynivalenol, deepoxy-deoxynivalenol, 3- and 15-acetyldeoxynivalenol, diacetoxyscirpenol, neosolaniol, fusarenon X, T-2 and HT-2 toxins, fumonisins B₁, B₂, and B₃, sterigmatocystin, and zearalenone were analyzed. Samples were treated by liquid-liquid extraction with acidified acetonitrile, followed by an acetonitrile-water phase separation using sodium acetate. The analysis was carried out by HPLC coupled to a triple quadrupole mass spectrometer. None of the analyzed mycotoxins had a concentration level higher than their detection limit (0.05–10.1 µg/L). The aflatoxin M₁ in the samples never exceeded the level established by the European Union.     

Simultaneous determination of type-A and type-B trichothecenes in barley samples by GC–MS

A validated method for the simultaneous determination of eight type-A and type-B trichothecenes in barley has been applied to the analysis of 44 samples from the 2007 harvest in Navarra (Spain). The procedure included simultaneous extraction of trichothecenes with acetonitrile and water (84:16), clean up with Multisep^® columns, derivatization of the extract and GC–MS analysis. During method validation, selectivity, linearity, precision and accuracy, limits of detection and quantification and recovery were evaluated. Recovery ranged from 92.0 to 101.9% (RSD < 15%), except for nivalenol (NIV) (63.1%), and the limits of detection and quantification ranged from 0.31 to 3.87 μg kg^?1 and from 10 to 20 μg kg^?1, respectively. The higher occurrence was found for deoxynivalenol (DON) (89% of the samples), although at concentrations below the maximum permitted level. The calculated dietary intakes of DON, NIV and the sum of T-2 and HT-2 were below the TDI values proposed. Two or more trichothecenes were present in 41% of the samples and so, the mycotoxin co-occurrence, and therefore synergic or additive effects, should be taking into account when determining permitted levels or risk assessment.     

Contribution to the study of ochratoxin A in Spanish wines.

With the aim of assessing ochratoxin A (OTA) contamination in wines from a Spanish northern region and the influence of harvest conditions, the following samples were analysed: 40 wines (28 red and 12 white) obtained from grapes cultivated in three different places of the northern Spanish region of Navarra, but in different years, 20 samples in 1997 and 20 in 1998. Wine samples were provided by a viticultural experimental station with very consistent and controlled cultural and enological practices. A high-performance liquid chromatography (HPLC) method with fluorescence detection and immunoaffinity columns was employed (LOD = 0.05 ng ml(-1); method recovery = 101%). Eighty five per cent of the samples from 1997 showed OTA levels >0.05 ng ml(-1) (range 0.056-0.316 ng ml(-1)) and 15% of the samples from 1998 showed OTA levels above the LOD (range 0.074-0.193 ng ml(-1)). Averages detected in 1997 positive samples were 0.185 ng OTA ml(-1) wine (SD = 0.023) in white wine samples (n = 6) and 0.160 ng ml(-1) (SD = 0.119) in the red wine samples (n = 11). These differences between contamination by OTA in the samples from the two different years were attributed to the different quality of the grapes, due to the bad climate in 1997. The possibility of the loss of the mycotoxin was excluded by the analysis of OTA in contaminated wine during 12 months. This study showed that OTA is stable in wine for at least 1 year.     

A simple chemical method reduces ochratoxin A in contaminated cocoa shells

Ochratoxin A (OTA) is a mycotoxin produced by Aspergillus and Penicillium species, which contaminates cocoa among other food commodities. It has been previously demonstrated that the toxin is concentrated in cocoa shells. The aim of this study was to assay a simple chemical method for ochratoxin A reduction from naturally contaminated cocoa shells. In order to determine the efficiency of the method, a high-performance liquid chromatography method with fluorescence detection was set up beforehand and validated. Ochratoxin A was extracted from cocoa shells with methanol-3% sodium bicarbonate solution and then purified with immunoaffinity columns. The recovery attained was 88.7% (relative standard deviation = 6.36%) and the limits of detection and quantification were 0.06 and 0.2 kg/kg, respectively. For decontamination experiments, the solvent extractor ASE 200 was used. First, aqueous solutions of 2% sodium bicarbonate and potassium carbonate were compared under the same conditions (1,500 lb/in2 at 40 degrees C for 10 min). Higher ochratoxin A reduction was obtained with potassium carbonate (83 versus 27%). Then, this salt was used under different conditions of pressure, temperature, and time. The greatest ochratoxin A reduction was achieved with an aqueous potassium carbonate solution (2%), at 1,000 lb/in2 at 90 degrees C for 10 min. This method could probably be applicable to the cocoa industry because it is fast and relatively economic. From the point of view of human health, the use of potassium carbonate, partially eliminated by rinsing the sample with water, does not likely represent a risk for human health.