Mycotoxin Ochratoxin Research Articles

Biomonitoring using dried blood spots: detection of ochratoxin A and its degradation product 2'R-ochratoxin A in blood from coffee drinkers.

ScopeIn this study, human exposure to the mycotoxin ochratoxin A (OTA) and its thermal degradation product 2’R‐ochratoxin A (2’R‐OTA, previously named as 14R‐Ochratoxin A [22]) through coffee consumption was assessed. LC‐MS/MS and the dried blood spot (DBS) technique were used for the analysis of blood samples from coffee and noncoffee drinkers (n = 50), and food frequency questionnaires were used to document coffee consumption.Methods and resultsFor the detection of OTA and 2’R‐OTA in blood, a new sensitive and efficient sample preparation method based on DBS was established and validated. Using this technique 2’R‐OTA was for the first time detected in biological samples. Comparison between coffee drinkers and noncoffee drinkers showed for the first time that 2’R‐OTA was only present in blood from the first group while OTA could be found in both groups in a mean concentration of 0.21 μg/L. 2’R‐OTA mean concentration was 0.11 μg/L with a maximum concentration of 0.414 μg/L. Thus, in average 2’R‐OTA was approx. half the concentration of OTA but in some cases even exceeded OTA levels. No correlation between the amounts of coffee consumption and OTA or 2’R‐OTA levels was observed.ConclusionThe results of this study revealed for the first time a high exposure of coffee consumers to 2’R‐OTA, a compound formed from OTA during coffee roasting. Since little information is available regarding toxicity and possible carcinogenicity of this compound, further OTA monitoring in blood including 2’R‐OTA is advisable.

Effects of Chronic Ochratoxin A Exposure on p53 Heterozygous and p53 Homozygous Mice.

Exposure to the mycotoxin ochratoxin A (OTA) causes nephropathy in domestic animals and rodents and renal tumors in rodents and poultry. Humans are exposed to OTA by consuming foods made with contaminated cereal grains and other commodities. Management of human health risks due to OTA exposure depends, in part, on establishing a mode of action (MOA) for OTA carcinogenesis. To further investigate OTA's MOA, p53 heterozygous (p53+/-) and p53 homozygous (p53+/+) mice were exposed to OTA in diet for 26 weeks. The former are susceptible to tumorigenesis upon chronic exposure to genotoxic carcinogens. OTA-induced renal damage but no tumors were observed in either strain, indicating that p53 heterozygosity conferred little additional sensitivity to OTA. Renal changes included dose-dependent increases in cellular proliferation, apoptosis, karyomegaly, and tubular degeneration in proximal tubules, which were consistent with ochratoxicosis. The lowest observed effect level for renal changes in p53+/- and p53+/+ mice was 200 μg OTA/kg bw/day. Based on the lack of tumors and the severity of renal and body weight changes at a maximum tolerated dose, the results were interpreted as suggestive of a primarily nongenotoxic (epigenetic) MOA for OTA carcinogenesis in this mouse model.

Ochratoxin A and ochratoxin-producing fungi on cereal grain in China: a review

The mycotoxin ochratoxin A (OTA) is known to be the main contaminant of cereal grain and has become increasingly important in recent years. Therefore, a survey of ochratoxigenic fungi and OTA contamination in China is a special challenge. This paper summarises data on cereals and moulds (Aspergillus niger, Penicillium verrucosum, Aspergillus ochraceus, for example) and on grain and OTA from 1973 by searching Chinese information databases (NCKI, VIP, DuXiu etc.), calculating the OTA-producing mould detection rate, referring to sampling locations, latitude and temperature, and also combining six grain-producing areas of ochratoxigenic fungi and OTA positive rate through a comprehensive analysis. It is concluded that in China rice (excluding shell rice) has less OTA contamination than wheat or maize. The contamination of cereal grains with Aspergillus section Nigri (formerly of the A. niger group) is a serious problem in China, and these fungi may be the main ochratoxigenic fungi on cereals.

Structure elucidation and in vitro cytotoxicity of ochratoxin α amide, a new degradation product of ochratoxin A.

The mycotoxin ochratoxin A is a secondary metabolite occurring in a wide range of commodities. During the exposure of ochratoxin A to white and blue light, a cleavage between the carbon atom C-14 and the nitrogen atom was described. As a reaction product, the new compound ochratoxin α amide has been proposed based on mass spectrometry (MS) experiments. In the following study, we observed that this compound is also formed at high temperatures such as used for example during coffee roasting and therefore represents a further thermal ochratoxin A degradation product. To confirm the structure of ochratoxin α amide, the compound was prepared in large scale and complete structure elucidation via nuclear magnetic resonance (NMR) and MS was performed. Additionally, first studies on the toxicity of ochratoxin α amide were performed using immortalized human kidney epithelial (IHKE) cells, a cell line known to be sensitive against ochratoxin A with an IC50 value of 0.5μM. Using this system, ochratoxin α amide revealed no cytotoxicity up to concentrations of 50μM. Thus, these results propose that the thermal degradation of ochratoxin A to ochratoxin α amide might be a detoxification process. Finally, we present a sample preparation and a HPLC-tandem mass spectrometry (HPLC-MS/MS) method for the analysis of ochratoxin α amide in extrudates and checked its formation during the extrusion of artificially contaminated wheat grits at 150 and 180°C, whereas no ochratoxin α amide was detectable under these conditions.

Ochratoxin A in Chinese dried jujube: method development and survey

A method was developed for the determination of the mycotoxin ochratoxin A in dried jujube (Zizyphus jujuba Miller) using alkaline methanolic extraction, immunoaffinity column clean-up (IAC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) determination. The limit of detection (LOD) was 0.01 μg kg–1 and limit of quantification (LOQ) was 0.03 μg kg–1. The average recoveries were 82%, 98% and 115% at 5, 0.5 and 0.1 μg kg–1 spiked levels with relative standard deviations (RSD) of 2.9%, 5.2% and 9.2% accordingly. The method showed good linearity for both solvent standard calibration and matrix-matched standard calibration with correlation coefficients of 0.9998 and 0.9997 respectively. The intra-day precision RSD was 3.3% and the inter-day precision RSD was 4.0%. In addition, there was almost no matrix interference in LC-MS/MS detection after the IAC clean-up process. The proposed analytical set-up was successfully used to test 20 samples that were collected from local markets and stores. The results showed that all the samples were positive and the amount of OTA ranged from < 0.01 to 0.18 μg kg–1, with a mean level of 0.14 μg kg–1. In spite of the high positive rate, samples with this level would not cause significant health effects after consumption.

Assessment and characterisation of yeast-based products intended to mitigate ochratoxin exposure using in vitro and in vivo models

The aim of this paper was to evaluate the capacity of several yeast-based products, derived from baker’s and brewer’s yeasts, to sequester the mycotoxin ochratoxin A (OTA) and to decrease its rate of absorption and DNA adduct formation in vivo. The experimental protocol included in vitro binding studies using isotherm models, in vivo chicken experiments, in which the serum and tissue concentrations of OTA were analysed in the absence and presence of the test compounds, and the profile of OTA-derived metabolites and their associated DNA adducts were determined. Additionally in vitro cell culture studies (HK2 cells) were applied to assess further the effects for yeast cell product enriched with glutathione (GSH) or selenium. Results of the in vitro binding assay in a buffer system indicated the ability of the yeast-based products, as sequester of OTA, albeit at a different level. In the in vitro experiments in chickens, decreased serum and tissue concentrations of treated animals confirmed that yeast-based products are able to prevent the absorption of OTA. A comparison of the binding affinity in a standard in vitro binding assay with the results obtained in an in vivo chicken experiment, however, showed a poor correlation and resulted in a different ranking of the products. More importantly, we could show that yeast-based products actively modulate the biotransformation of OTA in vivo as well as in vitro in a cell culture model. This effect seems to be attributable to residual enzymatic activities in the yeast-based products. An enrichment of yeast cell wall products with GSH or selenium further modulated the profile of the generated OTA metabolites and the associated pattern of OTA-induced DNA adducts by increasing the conversion of OTA into less toxic metabolites such as OTA, OTB and 4-OH-OTA. A reduced absorption and DNA adduct formation was particularly observed with GSH-enriched yeast, whereas selenium-enriched yeasts could counteract the OTA-induced decrease in cell viability, but at the same time increased the OTA–DNA adducts formation. These findings indicate the need for an in-depth characterisation of yeast-based products used as mycotoxin-mitigating feed additives, in in vivo models with target animal species taking into account not only their ability to sequester toxins in the gastrointestinal tract but also their potential effects on the biotransformation of mycotoxins.

In vitro genotoxicity of mycotoxins ochratoxin A and fumonisin B1 could be prevented by sodium copper chlorophyllin – Implication to their genotoxic mechanism

The aim of this study was to investigate the possible protective effect of sodium copper chlorophyllin (CHL) against cytotoxicity and DNA damage induced by mycotoxins ochratoxin A (OTA) and fumonisin B1 (FB1). CHL (0.1–100μg/ml) alone had no impact on cell viability and genome damage in the primary human peripheral blood lymphocytes (HPBLs) and exhibited free radical scavenging activity in the DPPH assay. Both mycotoxins, OTA (4μmol/l) and FB1 (20μg/ml), induced DNA damage in HPBLs already after 1h exposure. When the HPBLs were co-exposed to CHL (10 and 100μg/ml) and OTA (4μmol/l) or FB1 (20μg/ml) for 1h, CHL protected against cell and DNA damage induced by both mycotoxins, implying that OTA and FB1 cytogenotoxicity mechanisms function at least partially through oxidative stress. Therefore, CHL could be a perfect candidate for possible use as an antioxidant.

First biomonitoring data for the nephrotoxic mycotoxins citrinin and ochratoxin A in Bangladesh

First biomonitoring data for the nephrotoxic mycotoxins citrinin and ochratoxin A in Bangladesh

Ochratoxin A induced early hepatotoxicity: new mechanistic insights from microRNA, mRNA and proteomic profiling studies

AbstractThe mycotoxin ochratoxin A (OTA) is found widely in agricultural commodities. OTA can induce various toxicities. In this study, rats were gavaged with OTA for different weeks. Then, the expression of microRNAs, mRNAs and proteins were measured in the rat livers treated with OTA for 13 weeks. Our sequencing data suggests that the medial and the high doses of OTA exert different effects on livers. Five distinctive pathways were induced after OTA treatment as collectively demonstrated at miRNA, mRNA and protein levels. Two (primary bile acid biosynthesis and metabolism of xenobiotics by cytochrome P450) are directly associated with liver damage, whereas the remaining pathways (arginine and proline metabolism, cysteine and methionine metabolism and PPAR signaling pathway) cause metabolic disease. This study reveals OTA-induced early hepatotoxicity for the first time by combining multi-omics methods. The novel metabolic pathways may contribute to the pathogenesis of metabolic diseases later in life.

Repeated exposure to Ochratoxin A generates a neuroinflammatory response, characterized by neurodegenerative M1 microglial phenotype

Neurotoxic effects of the environmentally abundant mycotoxin Ochratoxin A (OTA) were studied in histotypic 3D rat brain cell cultures, comprising all brain cell types. Cultures were exposed to nanomolar OTA concentrations and samples were collected 48h after a single exposure, or after 10 days of repeated administration. OTA-induced changes in gene- and protein expression, as well as alterations in cell morphology were assessed.Forty-eight-hour OTA exposure resulted in a disruption of the neuronal cytoskeleton and reduced expression of several oligodendrocyte-specific markers indicative of demyelination. Astrocyte disturbances were revealed by a decrease in two astrocytic proteins involved in regulation of inflammatory responses, metallothioneins I and II. Repeated OTA administration induced a neuroinflammatory response, as visualized by an increase of isolectin B4 labelled cells, increased expression of pro-inflammatory cytokines, and detection of macrophagic ED1/CD68 positive cells, as well as an upregulation of neurodegenerative M1 microglial phenotype markers.Partial recovery from OTA-induced deleterious effects on oligodendrocytes and astrocytes was achieved by co-treatment with sonic hedgehog (SHH). In addition, metallothionein I and II co-treatment partially restored OTA-induced effects on oligodendrocytes after 48h, and modulated microglial reactivity after 10 days. These results suggest that OTA-exposure affects Shh-signalling, which in turn may influence both oligodendrocytes and astrocytes. Furthermore, the primarily astrocytic proteins MTI/MTII may affect microglial activation. Thus the neuroinflammatory response appears to be downstream of OTA-induced effects on demyelination, axonal instabilities and astrocytes disturbances. In conclusion, repeated OTA-exposure induced a secondary neuroinflammatory response characterized by neurodegenerative M1 microglial activation and pro-inflammatory response that could exacerbate the neurodegenerative process.

Matrix Binding of Ochratoxin A during Roasting

The mycotoxin ochratoxin A is degraded during coffee roasting by up to 90%. During this process, the two known degradation products, 14R-ochratoxin A and 14-decarboxy-ochratoxin A are formed. However, there is still an unexplained loss of more than 50% ochratoxin A. Here, we describe the binding of ochratoxin A to coffee polysaccharides via esterification as a further thermal reaction. This ester formation was studied by heating ochratoxin A with methyl α-d-glucopyranoside, a model compound to mimic polysaccharides. From this experiment, (22 → 6') ochratoxin A-methyl-α-d-glucopyranoside ester was isolated and characterized as a reaction product, showing the general ability of ochratoxin A for esterification with carbohydrates at roasting temperatures. Subsequently, a sample preparation protocol for the detection of ochratoxin A saccharide esters based on an enzymatic cleavage and purification using immunoaffinity chromatography was developed and applied. The detection was carried out by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Using this method, it was possible to detect ochratoxin A polysaccharide esters formed during roasting of artificially contaminated coffee, confirming the results of the previous model experiments. Thus, the formation of ochratoxin A esters is a further explanation for the loss of ochratoxin A during coffee roasting.

Exposure of infants to ochratoxin A with breast milk

The nephrotoxic and carcinogenic mycotoxin ochratoxin A (OTA) is a worldwide contaminant in food commodities and also found frequently in human biological fluids. Dietary contaminants ingested by nursing mothers can appear in breast milk. But the rate of lactational transfer of OTA has not been investigated so far at various stages of breastfeeding. Therefore, and to investigate OTA exposure of Chilean infants, we conducted a longitudinally designed study in mother-child pairs (n = 21) with parallel collection of maternal blood, milk and of infant urine samples over a period of up to 6 months. Validated analytical methods were applied to determine OTA concentrations in all biological samples (n = 134). OTA was detected in almost all maternal blood plasma, at concentrations ranging between 72 and 639 ng/L. The OTA concentrations in breast milk were on average one quarter of those measured in plasma (M/P ratio 0.25). Interestingly, a higher fraction of circulating OTA was excreted in colostrum (M/P 0.4) than with mature milk (M/P ≤ 0.2). Infants exposure was calculated as daily intake from our new data for OTA levels in breast milk, and taking into account milk consumption and body weight as additional variables: Chilean infants have an average intake of 12.7 ± 9.1 ng/kg bw during the first 6 days after delivery while intake with mature milk results in average values close to 5.0 ng/kg bw/day. Their OTA exposure is discussed in the context of tolerable intake values suggested by different scientific bodies. Moreover, the study design enabled a comparison of OTA intake and infant urine concentrations over the breastfeeding period. The statistical analysis of n = 27 paired values showed a good correlation (r = 0.57) for this type of studies and thereby confirms that urinary OTA analysis in infants is a valid biomarker of exposure.

Ochratoxin A levels in blood serum of Czech women in the first trimester of pregnancy and its correspondence with dietary intake of the mycotoxin contaminant

The mycotoxin ochratoxin A (OTA) can elicit a wide range of toxic properties including embryotoxicity and teratogenicity. OTA crosses the placenta at early gestation rather than in late gestation, maternal OTA exposure may represent a risk for the developing fetus. The study focuses on the assessment of OTA intake of pregnant women (aged 19–40 years) in the first trimester of pregnancy by means OTA levels in 100 blood serum samples by high-performance liquid chromotography with fluorescence detection (HPLC-FD) method and comparison with dietary OTA exposure in pregnant women. Of all, 96% tested serum samples were positive with values ranging from 0.1 to 0.35 µg/l with a mean value of 0.15 µg/l.

Ochratoxin A Mimotope from Second-Generation Peptide Library and Its Application in Immunoassay

With the advantage of replacing mycotoxins and their conjugates, mimotopes have been applied to immunoassays, the most common of which were seleted from random phage displayed peptide libraries. However, these mimotopes were limited by the diversities of the peptide libraries. The aim of this study was to demonstrate that a variety of mimotopes can be obtained by constructing a second-generation peptide library. Using mycotoxin ochratoxin A as a model system, a dodecapeptide mimotope was isolated after panning the second-generation peptide library. The half inhibition concentration of the chemiluminescent enzyme-linked immunosorbent assay setup with this mimotope was 0.04 ng/mL, and the linear range was 0.006-0.245 ng/mL. The mimotope was also used to develop a qualitative dipstick assay with a cutoff level of 1 ng/mL. The method not only presents a high sensitivity but also contributes to the development of mimotope-based assays for mycotoxins avoiding the need of synthesizing toxic mycotoxin conjugates.

Comparison of the accumulation of ochratoxin A residues in treated pig tissues

Driven by the observation that the mycotoxin ochratoxin A (OTA) often contaminates cereals and feed in this European region, the aim of the study was to compare the accumulation of OTA residues in different pig tissues exposed to sub-chronic treatment. The treated animal group (n = 5) was administered 300 μg OTA/kg of feed during a 30-day period, whereas the control group (n = 5) was left untreated. OTA concentrations were quantified using high performance liquid chromatography with fluorescence detection (HPLC-FD) that had shown acceptable validation results when it comes to all investigated tissues, with mean recoveries spanning from 88.2% to 96.1% and acceptable mean inter- and intra-day relative standard deviations (<10%). OTA concentrations determined in treated animal tissues ranged from 4.59 ± 1.45 μg/kg in the adipose tissue to 15.31 ± 2.77 μg/kg in the kidney. The results pointed out that sub-chronic pig exposure to the OTA dose frequently found in cereals and feed leads to the accumulation of OTA residues in the concentrations that are the highest in the kidney, then lungs, liver, blood, spleen, and heart, and the lowest in the adipose tissue.

Fungicides effectively used for growth inhibition of several fungi could induce mycotoxin biosynthesis in toxigenic species

Seven different commercial fungicides (Aliette, Rovral, Cantus, Ortiva, Luna Experience, Fenomenal and Mancozeb) were tested for their ability to inhibit the growth of the fungal species Penicillium nordicum, Penicillium verrucosum, Verticillium dahliae and Cladosporium sp. In case of the mycotoxigenic strains P. nordicum and P. verrucosum, the biosynthesis of the mycotoxins ochratoxin and citrinin was determined. Interestingly individual fungicides were only able to inhibit the growth of the analyzed fungi to some extent. In case of P. verrucosum the fungicide “Rovral”, an iprodion belonging to the substance class of imidazoles, led to a decrease in the growth rate but to a strong induction of mycotoxin biosynthesis as has been described earlier for the strobilurins. Consequently before using a given fungicide to protect crops and enhance storage life, the applicability of this chemical compound should be tested not only for its ability to inhibit fungal growth but also for its effect on level of secondary metabolite biosynthesis.

A review on ochratoxin A transcriptomic studies

The mycotoxin Ochratoxin A (OTA) is a potent renal carcinogen in male rats. Transcriptomic studies on OTA (4 in vitro, 6 in vivo, 2 in vitro/in vivo) have been reviewed. The aim of 6 of them was mainly mechanistic whereas the rest had mostly predictive (1) or evaluation (5) purposes. An overall tendency towards gene expression downregulation was observed, probably as a result of protein synthesis inhibition. DNA damage response genes were not deregulated in most of the studies. Genes involved in acute renal injury, cell survival and cell proliferation were upregulated in several in vivo studies. Apoptosis genes were deregulated in vitro but less affected in vivo; activation of several MAPKs has been observed. Many genes related to oxidative stress or involved in cell-to-cell interaction pathways (Wnt) or cytoskeleton structure appeared to be deregulated either in vitro or in vivo. Regucalcin was highly downregulated in vivo and other calcium homeostasis genes were significantly deregulated in vitro. Genes related to OTA transport (OATs) and metabolism (CYPs) appeared downregulated in vivo. Overall, the mechanism of action of OTA remains unclear, however transcriptomic data have contributed to new mechanistic hypothesis generation and to in vitro-in vivo comparison.

Intraspecific variability of HOG1 phosphorylation in Penicillium verrucosum reflects different adaptation levels to salt rich habitats

Mycotoxin biosynthesis in Penicillium verrucosum is modulated by different molecular regulation mechanisms. One important mechanism is the HOG1 (high osmolarity glycerol) MAP kinase signaling pathway. In a comparative analysis three different P. verrucosum strains were selected from six strains with different ability to produce the mycotoxins ochratoxin and citrinin. The fungal strains were grown on laboratory medium supplemented with different concentrations of NaCl. It could be shown that there exists an interrelationship between the growth rate, the level of HOG phosphorylation and the mycotoxin biosynthesis under the respective growth condition. The weak to non ochratoxin producing P. verrucosum strain, BFE875, showed only a poor growth rate but the strongest HOG1 phosphorylation; the strong ochratoxin and citrinin producing strain BFE575 showed a reasonable HOG1 phosphorylation with an average growth rate; and the strong ochratoxin and weak citrinin producing strain BFE495 showed only a poor phosphorylation but the highest growth rate in 7days of incubation at 25°C. The magnitude of phosphorylation of the HOG1 protein seems to be inversely correlated with the degree of adaption of the fungus to hyperosmotic growth conditions.

Effect of quercetin on the toxicokinetics of ochratoxin A in rats

Previous studies indicate that the intestinal absorption of the nephrotoxic mycotoxin ochratoxin A (OTA) occurs mainly through passive diffusion of the undissociated form. However, several in vitro studies have shown that OTA is partly re-secreted into the intestinal lumen by the multi-drug resistance associated protein (MRP2) and breast cancer resistance protein (BRCP). In vitro studies using Caco-2 cells have shown that some polyphenols (quercetin, genistein, resveratrol) may impair OTA efflux through competitive inhibition of MRP2, possibly resulting in an increased systemic availability of OTA. Among the tested polyphenols, quercetin showed the highest potential as efflux pump inhibitor; therefore, the aim of the present in vivo study was to investigate possible effects of quercetin on the toxicokinetics of OTA in rats. Eighteen growing male F344 Fisher rats (body weight: 200 g) were allocated to two dietary treatments consisting of (1) a commercial, flavonoid-free balanced diet containing 10 mg OTA/kg derived from inoculated wheat and (2) the same diet supplemented with 100 mg quercetin/kg. The animals were fed restrictively (~0.7 of ad libitum intake, 13 g/d) to avoid differences in OTA intake. Animals were kept in metabolism cages to facilitate total urine and faeces collection. After 6 days on trial, rats were euthanised and blood, liver, kidney, muscle and brain samples were taken from each animal. Faeces, urine and tissue samples were analysed for OTA and its main metabolite ochratoxin α by high-performance liquid chromatography using fluorescence detection. Quercetin supplementation had no effect (P > 0.05) on feed consumption, OTA-intake, water intake and body weight gain. Faecal and urinary excretion of OTA and ochratoxin α and concentrations of OTA in all tissues were not affected by quercetin supplementation. Based on the total excretion and tissue concentrations of OTA, it is concluded that the polyphenol quercetin has no impact on the toxicokinetics of OTA in vivo.

Effect of the mimic structure on the molecular recognition properties of molecularly imprinted polymers for ochratoxin A prepared by a fragmental approach

In this work the fragmental approach was used to prepare several molecularly imprinted ethylene dimethacrylate-co-methacrylic acid polymers with molecular recognition towards the mycotoxin ochratoxin A, with the aim of searching for simpler mimic templates than the well-known N-(4-chloro-1-hydroxy-2-naphthoylamido)-(l)-phenylalanine. The screening for binding of two different kinds of ochratoxin-related molecules was performed by HPLC analysis. Ochratoxin A and the mimic templates were eluted in acetonitrile–acetic acid (0.1%v/v) and the imprinting factor was measured for all the ligands on all the columns packed with the imprinted polymers. The experimental results show that changes to the amino acidic sub-structure or the presence/absence of a chlorine atom in position 4 on the naphthalene ring system does not affect the molecular recognition of ochratoxin A by the resulting imprinted polymer. On the contrary, the presence of the bulky naphthalene ring system in the mimic template seems to be necessary to preserve the molecular recognition of ochratoxin. This binding behavior was found to be compatible with in silico simulations of the complexation between some of the mimic templates and molecules of methacrylic acid. The use of the mimic template N-(1-hydroxy-2-naphthoylamido)-(L)-phenylalanine seems to represent a synthetically simple approach to the preparation of imprinted polymers with molecular recognition properties towards ochratoxin A.