Contribution to the study of ochratoxin A in Spanish wines

From Grapes to Wine: Impact of the Vinification Process on Ochratoxin A Contamination

Ochratoxin A (OTA) is one of the major mycotoxins, classified as "potentially carcinogenic to humans" (Group 2B) by the International Agency for Research on Cancer (IARC), and wine is one of its main sources of intake in human consumption. The main producer of this toxin is Aspergillus carbonarius, a fungus that contaminates grapes early in the growing season. The vinification process, as a whole, reduces the toxin content in wine compared to the grapes; however, not all vinification steps contribute equally to this reduction. During the maceration phase in red wines, toxin concentrations generally tend to increase. Based on previous studies, this review provides an overview of how each step of the vinification process influences the final OTA contamination in wine. Moreover, certain physical, chemical, and microbiological post-harvest strategies are useful in reducing OTA levels in wine. Among these, the use of fining agents, such as gelatin, egg albumin, and bentonite, must be considered. Therefore, this review describes the fate of OTA during the winemaking process, including quantitative data when available, and highlights actions able to reduce the final OTA level in wine.

Margin of Exposure Analyses and Overall Toxic Effects of Alcohol with Special Consideration of Carcinogenicity

Quantitative assessments of the health risk of the constituents of alcoholic beverages including ethanol are reported in the literature, generally with hepatotoxic effects considered as the endpoint. Risk assessment studies on minor compounds such as mycotoxins, metals, and other contaminants are also available on carcinogenicity as the endpoint. This review seeks to highlight population cancer risks due to alcohol consumption using the margin of exposure methodology. The individual and cumulative health risk contribution of each component in alcoholic beverages is highlighted. Overall, the results obtained consistently show that the ethanol contributes the bulk of harmful effects of alcoholic beverages, while all other compounds only contribute in a minor fashion (less than 1% compared to ethanol). Our data provide compelling evidence that policy should be focused on reducing total alcohol intake (recorded and unrecorded), while measures on other compounds should be only secondary to this goal.

Presence of 19 Mycotoxins in Human Plasma in a Region of Northern Spain

This study was conducted to investigate human exposure to 19 compounds (mycotoxins and their metabolites) in plasma samples from healthy adults (n = 438, aged 19-68 years) from Navarra, a region of northern Spain. Samples were analyzed by LC-MS/MS, before and after enzymatic hydrolysis for the detection of possible glucuronides and/or sulfates (Phase II metabolites). The most prevalent mycotoxin was ochratoxin A (OTA), with an incidence of 97.3%. Positive samples were in the concentration range of 0.4 ng/mL to 45.7 ng/mL. After enzymatic treatment, OTA levels increased in a percentage of individuals, which may indicate the presence of OTA-conjugates. Regarding ochratoxin B, it has also been detected (10% of the samples), and its presence may be related to human metabolism of OTA. Sterigmatocystin was detected with a high incidence (85.8%), but only after enzymatic hydrolysis, supporting glucuronidation as a pathway of its metabolism in humans. None of the other studied mycotoxins (aflatoxins B1, B2, G1, G2 and M1; T-2 and HT-2 toxins; deoxynivalenol, deepoxy-deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol; zearalenone; nivalenol; fusarenon-X; neosolaniol; and diacetoxyscirpenol) were detected in any of the samples, neither before nor after enzymatic treatment. To the best of our knowledge, this is the first report carried out in Spain to determine the exposure of the population to mycotoxins and some of their metabolites using plasma, and the obtained results justify the need for human biomonitoring and metabolism studies on mycotoxins.

Ochratoxigenic fungi and Ochratoxin A determination in dried grapes marketed in Tunisia

Purpose

With the present work, we aimed to assess the occurrence of ochratoxigenic fungi and Ochratoxin A (OTA) in dried grapes from Tunisia.

Methods

Dried 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.

Results

Black 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.

Conclusion

According 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.

Biodiversity and ochratoxin A profile of Aspergillus section Nigri populations isolated from wine grapes in Cyprus vineyards

The objective of this study was to evaluate the biodiversity of Aspergillus section Nigri populations from Cyprus vineyards by morphological, toxigenic and phylogenetic analysis. Aspergillus section Nigri populations were isolated from grapes of the varieties 'Maratheftiko' and 'Cabernet Sauvignon' originating from six growing regions of Cyprus during 2010 and 2011 years. The isolation frequency of Aspergillus section Nigri from grape samples was 43.3% and a total of 284 isolates were selected for further analyses based on the macroscopic characteristics of black aspergilli. The isolates were characterized by sequencing analysis of the calmodulin gene in order to identify species responsible for ochratoxin A (OTA) production. The phylogenetic analysis showed that the isolates were grouped in three major clusters. The A. tubingensis cluster included 262 isolates (92.25%), the A. niger cluster included 15 isolates identified as A. niger (5.3%) and 6 isolates identified as A. welwitschiae (2.1%). One isolate was classified as A. carbonarius (0.35%) and was grouped in a cluster together with the reference isolates of A. carbonarius, A. sclerotioniger, A. sclerotiocarbonarius and A. ibericus. All the isolates were evaluated for their ochratoxigenic ability by HPLC coupled with a fluorescence detector (HPLC-FLD) and the positive isolates were re-examined using ultra high-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS). The Aspergillus carbonarius isolate produced an average quantity of 1436.1 ng OTA/g Czapek Yeast Agar (CYA); From the A. niger strains three isolates (20%) produced OTA and only one isolate from A. welwitschiae (16.7%) was proved ochratoxigenic with toxin production average at 23.9 ng/g and 9.1 ng/g CYA respectively. Grape must samples derived from the collected berries were also analyzed for OTA and none of the samples were found contaminated with the mycotoxin. The results showed that the geographic area and the meteorological conditions had no significant effect on the incidence and the distribution of black aspergilli in this 2-year project. However, absence of rainfall and low humidity during the harvesting period were critical for the low incidence of the ochratoxigenic A. carbonarius on grapes.

Grape and environmental mycoflora monitoring in old, traditionally cultivated vineyards on Mount Etna, southern Italy

BACKGROUND

Grape contamination by several fungal species occurs during a vineyard's preharvest and harvest. Agronomic management and microclimatic conditions can affect fungi occurrence and epidemiology, thus explaining qualitative differences in mycoflora composition, including the presence of phytopathogenic or mycotoxigenic fungi. In this study a two-year grape, air and soil mycoflora monitoring programme was undertaken in vineyards on Mount Etna (eastern Sicily, Italy). The mycoflora composition was investigated at pea berry and veraison phenological phases from air and soil and at ripening from sample grapes.

RESULTS

Mycoflora in air and soil varied according to the phenological stage. In the air samples, penicillia were dominant over aspergilli at the pea berry phase, but their ratio was inverted at early veraison. Black aspergilli (BA) were isolated from the vine environment and grape samples, where BA were represented mainly by Aspergillus niger aggregate, which showed no or low ochratoxin A (OTA) production. Aspergillus carbonarius was either not identified or identified at low frequency, although most of the isolates produced OTA.

CONCLUSION

Monitoring focused on the environmental mycoflora composition and highlighted the good health profile of various Sicilian autochthonous grape cultivars. In addition, data suggest that the lower relative humidity occurring at the highest altitudes reduces BA incidence. © 2016 Society of Chemical Industry.

Carcinogenic compounds in alcoholic beverages: an update

The consumption of alcoholic beverages has been classified as carcinogenic to humans by the International Agency for Research on Cancer (IARC) since 1988. More recently, in 2010, ethanol as the major constituent of alcoholic beverages and its metabolite acetaldehyde were also classified as carcinogenic to humans. Alcoholic beverages as multi-component mixtures may additionally contain further known or suspected human carcinogens as constituent or contaminant. This review will discuss the occurrence and toxicology of eighteen carcinogenic compounds (acetaldehyde, acrylamide, aflatoxins, arsenic, benzene, cadmium, ethanol, ethyl carbamate, formaldehyde, furan, glyphosate, lead, 3-MCPD, 4-methylimidazole, N-nitrosodimethylamine, pulegone, ochratoxin A, safrole) occurring in alcoholic beverages as identified based on monograph reviews by the IARC. For most of the compounds of alcoholic beverages, quantitative risk assessment provided evidence for only a very low risk (such as margins of exposure above 10,000). The highest risk was found for ethanol, which may reach exposures in ranges known to increase the cancer risk even at moderate drinking (margin of exposure around 1). Other constituents that could pose a risk to the drinker were inorganic lead, arsenic, acetaldehyde, cadmium and ethyl carbamate, for most of which mitigation by good manufacturing practices is possible. Nevertheless, due to the major effect of ethanol, the cancer burden due to alcohol consumption can only be reduced by reducing alcohol consumption in general or by lowering the alcoholic strength of beverages.

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.

Biodiversity and ITS-RFLP characterisation of Aspergillus section Nigri isolates in grapes from four traditional grape-producing areas in Greece

A study on the occurrence of Aspergillus section Nigri species on grapes from four traditional grape-producing areas in Greece during the 2011/2012 vintage, and their capability to produce OTA was conducted. One hundred and twenty-eight black aspergilli isolates were characterised at the species level initially by the use of morphological criteria in accordance with appropriate keys, followed by molecular characterisation performed with Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) of the 5.8 ribosomal RNA gene Internal Transcribed Spacer region (5.8 rRNA ITS). Restriction enzyme digestion of the ITS amplicons using the HhaI, HinfI and RsaI, endonucleases distinguished eleven different patterns of restriction fragment length polymorphism (RFLP), four for each of the HhaI and RsaI digests and three for HinfI. From a total number of 128 individual isolates, 124 were classified into four Aspergillus species corresponding to A. carbonarius, A. tubingensis, A. japonicus and A. ibericus, and the remaining 4 were classified as members of the A. niger aggregate. A. carbonarius and A. tubingensis being the main representative species were equally counted, with higher geographical representation of the former in southern and the latter in northern regions, respectively. All isolates were tested for their ochratoxigenic potential by use of High Performance Liquid Chromatography (HPLC) and Enzyme Linked Immuno Sorbent Assay (ELISA), resulting in significant interspecies differences in OTA production.

Wine features related to safety and consumer health: an integrated perspective

This review presents a global view of the current situation of the scientific knowledge about aspects of wine with possible repercussions (positive or negative) on consumer health and wine safety. The presence in wine of some potential harmful compounds such as phytosanitary products, trace metal compounds, sulfites, and some toxics of microbial origin, such as ochratoxin A, ethyl carbamate, and biogenic amines, is discussed. The different strategies and alternative methodologies that are being carried out to reduce or to avoid the presence of these substances in wines are also discussed. In recent years much work has focused on establishing the scientific explanations for the positive biological effects of some wine compounds. In this review, we also examine the latest knowledge regarding wine and health, focusing on two types of compounds that have been related to the positive effects of moderate wine consumption, such as phenolic compounds and bioactive peptides.

Ochratoxigenic black species of Aspergilli in grape fruits of northern Italy identified by an improved PCR-RFLP procedure

A collection of 356 isolates of Aspergillus spp. collected during 2006 and 2007 from grapevines in northern Italy were identified through Internal Transcribed Spacer based Restriction Fragment Length Polymorphism (ITS-RFLP) and tested for ochratoxin A (OTA) production. Restriction endonuclease digestion of the ITS products using the endonucleases HhaI, HinfI and RsaI, distinguished five different RFLPs. From each pattern, three samples were sequenced and the nucleotide sequences showed different species corresponding to Aspergillus niger, A. carbonarius, A. tubingensis, A. japonicus and A. aculeatus. By comparing the sequences of the ITS regions, also the uniseriate species A. japonicus and A. aculeatus could be differentiated by HinfI digestion of the ITS products. Among the aspergilli, A. niger was the major species associated with grapes during 2006 (57.4%), while A. carbonarius was the major species during 2007 (46.6%). All the strains of Aspergillus were tested for their ability to produce OTA on Yeast extract sucrose medium (YES), as it was tested as an optimal substrate for the evaluation of OTA production by black aspergilli. Out of 356 isolates, 63 (17.7%) isolates produced OTA ranging from 0.05 to 3.0 µg mL(-1). Most of the ochratoxigenic isolates were A. carbonarius (46) in both years, but also some strains of A. tubingensis (11) and A. japonicus (6) produced lower amounts of OTA.

Detection of ochratoxin A and cis- and trans-resveratrol in red wines and their musts from Calabria (Italy)

The natural occurrence of ochratoxin A (OTA) and cis- and trans-resveratrols in red wines has been widely reported. The aim of this work was to evaluate the ochratoxin A (OTA) and both cis- and trans-resveratrol content of red wine (from must to wine) in a pilot-scale vinification process in Calabria (Italy). Eleven samples were collected at different stages of vinification and analysis was carried out by HPLC. Wine from manufacturer 3 contained the highest amount of trans-resveratrol (3.41 mg l(-1)). This wine was characterized by an Aglianico-Magliocco grape variety. Interestingly, data regarding OTA showed that the value of this contaminant was low in all analyzed samples and, in each case, below the legal limit (2.0 mg l(-1) (ppb)). Overall, the results demonstrated the high quality of wines produced in Calabria.

Changes of ochratoxin A in grapes inoculated with Aspergillus carbonarius and subjected to chamber-drying under controlled conditions

The production pattern for ochratoxin A in grapes inoculated with Aspergillus carbonarius and changes in its concentration during raisining of Merlot, Syrah, Tempranillo, and Cabernet Sauvignon red grapes and Pedro Ximenez white grape were studied. Grapes were chamber-dried under controlled temperature and humidity conditions, with and without dipping pretreatments in alkaline emulsions of olive oil or ethyl oleate. Based on the results for the grapes that developed the fungus (Merlot and Pedro Ximenez), a temperature of 50 °C in the absence of dipping stopped ochratoxin A production and even degraded part of the toxin already formed. Both dipping pretreatments facilitated removal of the toxin and led to its virtually complete disappearance. However, dipping in the ethyl oleate emulsion caused substantial changes in the sensory characters of the musts obtained from the raisins, so it should be avoided to ensure the expected quality in the sweet wines elaborated from them.

Mycotoxins in grapes and wine in Europe: occurrence, factors affecting the occurrence and related toxicological effects

In 2006, the European Commission has established maximum levels for ochratoxin A in wine and grape products, using occurrence data up to 2001 and toxicity data up to 2006. This paper presents an up-to-date overview of the occurrence of mycotoxins in grapes and wine produced in Europe in the period 1995-2010. In addition, for the most frequently occurring mycotoxins, factors influencing the occurrence, and the toxicological effects are presented. To evaluate possible trends in occurrence, contamination data were grouped into three periods of time, i.e. 1995-1999, 2000-2006 and 2007-2010. Most of the available contamination data on mycotoxins in grapes and wine refer to ochratoxin A, but occurrence data on this toxin from 2006 onwards are very limited. The occurrence of ochratoxin A is higher in the southern European countries than in the northern countries, and higher in red and sweet wines as compared to white wines. Fumonisins occur frequently, but in low concentrations. Data on the natural occurrence of Alternaria toxins are not available. The most important factors that influence ochratoxin A contamination of grapes and wine include: temperature and relative humidity in the month before harvesting the berries, the type of wine (maceration), and the percentage of damaged berries before vinification. Applying good agricultural practices in the vineyard, including minimizing damaged berries and chemical or biological control of the fungi, are the best methods to limit mycotoxin formation in grapes and wine. Ochratoxin A, Alternaria toxins and fumonisins are toxic to animals. These toxins are of concern to human health, but clear evidence on their relationship with human disease is not available yet. Therefore, more research in this area would be desirable.

Aspergillus carbonarius growth and ochratoxin A production on irradiated dried grapes under different water activity and temperature conditions

Grapes have different destinations. The most important in the national and international market is wine production, but another is dehydration to produce raisins. Dried vine fruits are at greater risk of ochratoxin A (OTA) contamination than wine grapes because the ratio of Aspergillus carbonarius to Aspergillus niger aggregate increases during drying. The growth of these species, and consequently OTA production, can be influenced by different environmental factors, the two most important being water activity (aW) and temperature. The objective of the present work was to evaluate the lag phase, growth rate and OTA production by two A. carbonarius isolates on irradiated dried grapes at different aW (0.910, 0.928, 0.955, 0.973 and 0.995), temperatures (15, 25 and 30 °C) and incubation times (7, 14 and 21 days). Growth was observed at all aW and temperature ranges assayed. No significant differences between the growth rates reached at 25 °C and 30 °C by both isolates were observed. At the assayed conditions, OTA production occurred over the whole range of temperatures (15-30 °C), with the maximum at 25 and 30 °C depending on the aW. In general, OTA concentration increased as aW increased with no statistically significant differences at the tested incubation times. This work provides information that can be used by companies for the purpose of preventing A. carbonarius and OTA contamination during storage on this and other substrates (e.g. dried prunes, figs and apricots) destined for human consumption.

Occurrence of ochratoxin A in Southern Spanish generous wines under the denomination of Origin "Jerez-Xérès-Sherry and 'manzanilla' Sanlúcar de Barrameda"

The mycotoxin ochratoxin A (OTA) has toxic effects in animals; the most relevant of them is nephrotoxicity. OTA has also been classified as a possible carcinogen for humans (group 2B) by the International Agency for Research on Cancer (IARC). Therefore, exposure to OTA through contaminated food can represent health impairment to humans. The maximum permitted level for this mycotoxin in wine is 2.0 μg/L. The presence of OTA in Spanish wines produced using the traditional methods under the Denomination of Origin "Jerez-Xérès-Sherry andmanzanilla Sanlúcar de Barrameda" was evaluated by a High performance Liquid Chromatography method with fluorescence detection and immunoaffinity column purification. A recovery of 95.4% and a limit of detection and quantification of 0.009 μg/L and 0.02 μg/L respectively, were achieved. In manzanilla, fino, amontillado and oloroso wine, the mean OTA values were 0.042, 0.044, 0.144, and 0.319 μg/L, respectively. These levels are not different from other data given in the reference literature on white wines, although fino and manzanilla wines have very low OTA levels.

Occurrence of black aspergilli and ochratoxin A on grapes in Italy

Ochratoxin A (OTA) in wine is linked to contamination by several Aspergillus species. In 2003–2007, grape samples collected in Italy were surveyed for the presence of OTA and OTA-producing fungi. A. niger aggregate was the prevalent species. A. carbonarius, which is considered the main source of OTA in grapes, was mostly found in Southern Italy. The year and the environment had an important influence on the development of the black Aspergillus populations. Testing with ELISA showed OTA to be present in about 30% of the samples. Samples from Southern Italy showed the highest occurrence (45%) and also the highest OTA concentration, sometimes higher than 2 μg/L. The values decreased progressively the further North the samples were taken.

Ochratoxin a: general overview and actual molecular status

Ochratoxin A (OTA) is a mycotoxin produced by several species of Aspergillus and Penicillium fungi that structurally consists of a para-chlorophenolic group containing a dihydroisocoumarin moiety that is amide-linked to L-phenylalanine. OTA is detected worldwide in various food and feed sources. Studies show that this molecule can have several toxicological effects such as nephrotoxic, hepatotoxic, neurotoxic, teratogenic and immunotoxic. A role in the etiology of Balkan endemic nephropathy and its association to urinary tract tumors has been also proved. In this review, we will explore the general aspect of OTA: physico-chemical properties, toxicological profile, OTA producing fungi, contaminated food, regulation, legislation and analytical methods. Due to lack of sufficient information related to the molecular background, this paper will discuss in detail the recent advances in molecular biology of OTA biosynthesis, based on information and on new data about identification and characterization of ochratoxin biosynthetic genes in both Penicillium and Aspergillus species. This review will also cover the development of the molecular methods for the detection and quantification of OTA producing fungi in various foodstuffs.

Ochratoxin A in wine consumers in Italy: dietary profiles

The study was carried out on a group of wine consumers, healthy adults, living in one of the areas in Southern Italy, where the ochratoxin A (OTA) levels in wines were very high. OTA levels in consumed wine ranged from 0.2 to 2 ng/ml for 80% of the samples and from 2.10 to 5.40 ng/ml for the other 20%. OTA values in blood (exposure) were lower than 0.28 ng/ml for 30% of the subjects, ranged from 0.28 to 0.34 ng/ml for 43% of the subjects, and reached more than 0.34 ng/ml for 27% of the subjects. Mean OTA measured in urine was 0.43 ng/ml. No significant correlation was found between OTA concentration in blood and in consumed wine, neither between OTA in blood and ingestion levels. OTA levels were determined by HPLC. Individual food consumption habits, gathered in a questionnaire, were studied in association with experimental exposure by means of multiple correspondence analysis. Subjects consuming one or two glasses of red home-produced wine daily were characterised by medium exposure, while those consuming three glasses or half a litre per occasion showed a high exposure; low exposure was associated with weekly consumption of white commercial wine. High quantities of beer and daily consumption of bread and pasta characterised habitual wine consumers, while weekly consumption of beer, bread and chocolate characterised moderate wine consumers.

Occurrence of ochratoxin A in sweet wines produced in Spain and other countries

A survey for the presence of ochratoxin A (OTA) was undertaken from 2001 to 2005 in 188 samples of sweet wines produced in Spain and in 102 samples originating from other countries: France (n = 49), Austria (9), Chile (9), Portugal (9), Greece (6), Italy (5), Germany (3), Hungary (2), Slovenia (2), Switzerland (2), Canada (1), Japan (1), New Zealand (1), Ukraine (1), South Africa (1) and the USA (1). The analytical method was based on immunoaffinity chromatography clean-up and high-performance liquid chromatography (HPLC) with fluorescence detection. The limit of detection (defined as a signal-noise ratio = 3) was estimated to be 0.01 microg l(-1). The limit of quantification (0.02 microg l(-1)) was checked as being the lowest measurable concentration. OTA was detected in 281 out of 290 samples analysed (96.9% positive) at concentrations ranging from 0.01 to 4.63 microg l(-1). The overall mean and median levels were estimated to be 0.50 and 0.14 microg l(-1), respectively. In Spanish sweet wines OTA was found in 99% of the samples, with mean and median values of 0.65 and 0.19 microg l(-1), respectively. The mean value obtained in this study for OTA in the Spanish sweet wines would result in an intake of about 37.5 and 3.2 ng day(-1) of OTA for regular consumers and for the overall population, respectively. These figures represent a minor contribution to the provisional tolerable weekly intake (PTWI) or TWI established by the Joint Expert Committee on Food Additives (JECFA) and the European Food Safety Authority: 3.8 and 3.1% for regular consumers; and 0.4 and 0.3% for the whole adult population, respectively.

An ITS-RFLP method to identify black Aspergillus isolates responsible for OTA contamination in grapes and wine

Ochratoxigenic mycobiota in grapes from representative wine regions in Valencia was identified. Black aspergilli were predominant among the different Aspergillus spp. isolated. Restriction digestion analysis of the ITS products was tested as a rapid method to identify isolates of black Aspergillus species from grapes. Restriction endonuclease digestion of the ITS products using the endonucleases HhaI, NlaIII and RsaI, distinguished five types of restriction fragment length polymorphism (RFLP) corresponding to Aspergillus niger, Aspergillus tubingensis, Aspergillus carbonarius and Aspergillus aculeatus species. In addition, a new RFLP type in the A. niger aggregate was identified. The fragments obtained by digestion with the endonuclease NlaIII could be used to identify these new isolates. Black Aspergillus isolates were tested for their ability to produce OTA. Most of the isolates that produced ochratoxin A in YES medium belonged to A. carbonarius species. These results support evidence that A. carbonarious greatly contributes to OTA contamination in grapes and consequently in wine. The ITS-RFLP assay is proposed as a rapid and easy method to identify black Aspergillus species isolated from grapes, especially in studies that involve a large number of isolates.

Strategies to Prevent Mycotoxin Contamination of Food and Animal Feed: A Review

Mycotoxins are fungal secondary metabolites that have been associated with severe toxic effects to vertebrates produced by many important phytopathogenic and food spoilage fungi including Aspergillus, Penicillium, Fusarium, and Alternaria species. The contamination of foods and animal feeds with mycotoxins is a worldwide problem. We reviewed various control strategies to prevent the growth of mycotoxigenic fungi as well as to inhibit mycotoxin biosynthesis including pre-harvest (resistance varieties, field management and the use of biological and chemical agents), harvest management, and post-harvest (improving of drying and storage conditions, the use of natural and chemical agents, and irradiation) applications. While much work in this area has been performed on the most economically important mycotoxins, aflatoxin B(1) and ochratoxin A much less information is available on other mycotoxins such as trichothecenes, fumonisin B(1), zearalenone, citrinin, and patulin. In addition, physical, chemical, and biological detoxification methods used to prevent exposure to the toxic and carcinogenic effect of mycotoxins are discussed. Finally, dietary strategies, which are one of the most recent approaches to counteract the mycotoxin problem with special emphasis on in vivo and in vitro efficacy of several of binding agents (activated carbons, hydrated sodium calcium aluminosilicate, bentonite, zeolites, and lactic acid bacteria) have also been reviewed.

Ochratoxin A in red paprika: relationship with the origin of the raw material

The occurrence of ochratoxin A (OA) in paprika elaborated from peppers grown in several countries (Peru, Brazil, Zimbabwe and Spain) was studied, using an immunoaffinity clean-up column coupled to liquid chromatography and fluorescence detection. The preparation of the methyl ester (OA-Me) and liquid chromatography-electrospray-ion trap-mass spectrometry was used both to confirm the identity of the chromatographic peak that correspond to OA and to quantify it at low levels or in dirty fractions. A total of 115 strains of moulds were isolated; 85 of the fungal strains were obtained from OA contaminated paprika samples and identified as belonging to the Aspergillus Section Circumdati group (A. ochraceus) and Section Nigri group (A. niger, A. carbonarius). Among the latter ones, 31% of the A. ochraceus isolates and one A. niger were OA producers in vitro. None of the mould strains isolated from paprika samples with undetectable levels of OA or concentrations below 1 microg kg(-1) were toxin producers. Great differences in OA content in paprika samples were found, and a relationship with the climatic conditions of the geographic origin of the samples, and with cultural and technical practices in pepper manipulation is suggested.

European research on ochratoxin A in grapes and wine

European wine production represents about 70% of world production and thus is an important export commodity. Ochratoxin A (OTA) was first detected as a wine contaminant in 1996 and the role of Aspergillus section Nigri and A. carbonarius in OTA production discovered in Europe in 1999. Subsequently Europe-wide surveys have shown that A. carbonarius is predominantly responsible for OTA contamination of grapes, wine and vine fruits. Analyses of wine samples throughout Europe have shown that there is a gradient in OTA concentration with a decrease from red, to rose and to white wines. The latitude of production is an important factor in determining risk from OTA contamination. Some geographic regions in Southern Europe are more prone to contamination with the toxigenic species and OTA. Ochratoxin A has also been found in much higher concentrations (max. 53 mug/kg) in dried vine fruit than in wine suggesting that A. carbonarius can dominate the drying vine fruit ecosystem. There is a significant lack of knowledge in Europe on conducive climatic conditions preharvest and their relationship with levels of risk from OTA contamination in grapes and their fate in wine production. This needs to be integrated with cultivation system to maximise the prevention of OTA entering this food chain.

Ochratoxin a: its cancer risk and potential for exposure

Ochratoxin A (OA) is a naturally occurring mycotoxin known to contaminate a variety of foods and beverages. The cancer risk posed by OA was reviewed as relevant to human exposure, regulatory activities, and risk management efforts occurring worldwide, particularly in Europe. OA moves through the food chain and has been found in the tissues and organs of animals, including human blood and breast milk. Results from the National Toxicology Program's rodent bioassays show significantly increased incidence of mammary gland tumors in female rats and kidney tumors in male and female rats given OA orally. Liver tumors in female mice fed OA in the diet have also been observed. In humans, OA exposure has been most often associated with the kidney disease Balkan endemic nephropathy (BEN), symptoms of which include tumors of the kidney and urinary tract. No epidemiological studies have yet adequately evaluated the cancer risk of OA in human populations. Studies have shown OA to be genotoxic as well as immunotoxic, although its mode of action is not fully understood. Organizations and agencies in many countries are currently promulgating standards for OA in foods and beverages. Increased efforts in farm management and food safety are being made to mitigate the risks to public health posed by OA. The U.S. Food and Drug Administration (FDA) is currently evaluating data on OA levels in domestic and imported commodities but has not established official regulations or guidelines for OA in the U.S. food supply.

Immunotoxic activity of ochratoxin A

Ochratoxin A (OTA) is an immunosuppressant fungal compound, produced by toxigenic species of Aspergillus and Penicillium fungi in a wide variety of climates and geographical regions. The contamination of food by this mycotoxin takes place primarily during preharvest periods. Almost all types of food can be contaminated. In addition, its chemical stability against heat and during industrial food processing makes OTA one of the most abundant food contaminating mycotoxins. Due in part to its long serum half-life in man, almost 100% of all human blood samples from some geographic regions may be positive for OTA. The immunosuppressant activity of OTA is characterized by size reduction of vital immune organs, such as thymus, spleen, and lymph nodes, depression of antibody responses, alterations in the number and functions of immune cells, and modulation of cytokine production. The immunotoxic activity of OTA probably results from degenerative changes and cell death following necrosis and apoptosis, in combination with slow replacement of affected immune cells, due to inhibition of protein synthesis.

Study of Spanish grape mycobiota and ochratoxin A production by Isolates of Aspergillus tubingensis and other members of Aspergillus section Nigri

The native mycobiota of five grape varieties grown in Spain has been studied. Four (Bobal, Tempranillo, Garnacha, and Monastrell) were red varieties and one (Moscatel) was white. The main fungal genera isolated were Alternaria, Cladosporium, and Aspergillus. The isolation frequency of Aspergillus spp. section Nigri in contaminated samples was 82%. Ochratoxin A (OTA) production was assessed using yeast extract-sucrose broth supplemented with 5% bee pollen. Cultures of 205 isolates from this section showed that 74.2% of Aspergillus carbonarius and 14.3% of Aspergillus tubingensis isolates produced OTA at levels ranging from 1.2 to 3,530 ng/ml and from 46.4 to 111.5 ng/ml, respectively. No Aspergillus niger isolate had the ability to produce this toxin under the conditions assayed. Identification of the A. niger aggregate isolates was based on PCR amplification of 5.8S rRNA genes and its two intergenic spacers, internal transcribed spacer 1 (ITS1) and ITS2, followed by digestion with restriction endonuclease RsaI of the PCR products. The restriction patterns were compared with those from strains of A. niger CECT 2807 and A. tubingensis CECT 20393, held at the Spanish Collection of Type Cultures. DNA sequencing of the ITS1-5.8S rRNA gene-ITS2 region of the OTA-producing isolates of A. tubingensis matched 99 to 100% with the nucleotide sequence of strain A. tubingensis CBS 643.92. OTA determination was accomplished by liquid chromatography with fluorescence detection. OTA confirmation was carried out by liquid chromatography coupled to ion trap mass spectrometry. The results showed that there are significant differences with regard to the isolation frequency of ochratoxinogenic fungi in the different grape varieties. These differences were uncorrelated to berry color. The ability of A. tubingensis to produce OTA and the influence of grape variety on the occurrence of OTA-producing fungi in grapes are described in this report for the first time.

Production and stability of patulin, ochratoxin A, citrinin, and cyclopiazonic acid on dry cured ham

Toxinogenic fungal species can be isolated from dry cured meat products, raising the problem of the direct contamination of these foods by mycotoxins known to be carcinogenic or potent carcinogens. Because the contamination of a food by mycotoxins can be considered a balance between production and degradation, the stability of mycotoxins on dry cured meat was also investigated. This study focused on patulin, ochratoxin A, citrinin, and cyclopiazonic acid that can be produced by fungal species previously isolated from dry cured meat products sold on the French market. We demonstrated that neither patulin nor ochratoxin A was produced on dry meat by toxigenic strains, whereas relatively high amounts of citrinin and cyclopiazonic acid were found after a 16-day incubation period at 20 degrees C (87 and 50 mg/kg, respectively). After direct contamination, the initial content of patulin rapidly decreased to become undetectable after only 6 h of incubation at 20 degrees C. For both citrinin and ochratoxin A, the kinetics of decrease at 20 degrees C was less rapid, and the two toxins presented half-lives of 6 and 120 h, respectively. By contrast, more than 80% of the initial contamination in cyclopiazonic acid was still found on ham after a 192-h incubation period. Toxin stability was not affected by storage at 4 degrees C. These results suggest that growth of toxigenic strains of Penicillium has to be avoided on dry meat products.

Ochratoxigenic species from Spanish wine grapes

The ochratoxigenic mycobiota of grapes belonging to representative wine regions located along the Mediterranean coast of Spain at different developmental stages was identified. During the development of the berries, the occurrence of Aspergillus spp. increased while the percentage of berries contaminated by non-ochratoxin A (OTA) producing species such as Alternaria spp. and Cladosporium spp. decreased. Penicillium verrucosum, the only confirmed Penicillium spp. that is able to produce OTA, was not isolated. The contamination by OTA-producing species comes from the surface of the berries and not from the inner fruit. Black aspergilli were predominant among the different Aspergillus spp. isolated. All the Aspergillus carbonarius isolates were able to produce OTA at different concentrations. None of the isolates belonging to Aspergillus niger aggregate and to Aspergillus japonicus var. aculeatus were able to produce OTA. These results are a strong evidence of the contribution of A. carbonarius in the OTA contamination in wine grapes, mainly at the last developmental stages of the berries.