The effects of milling and processing on wheat contaminated with ochratoxin A

Practical Strategies to Reduce Ochratoxin A in Foods

Ochratoxin A (OTA), a potent nephrotoxin, is one of the most deleterious mycotoxins, with its prevalence in agricultural crops and their processed foods around the world. OTA is a major concern to food safety, as OTA exposure through dietary intake may lead to a significant level of accumulation in the body as a result of its long half-life (about 35 days). Its potent renal toxicity and high risk of exposure as well as the difficulty in controlling environmental factors OTA production has prompted the need for timely information on practical strategies for the food industry to effectively manage OTA contamination during food processing. The effects of various food processes, including both nonthermal and thermal methods, on the reduction in OTA were summarized in this review, with emphasis on the toxicity of residual OTA as well as its known and unknown degradation products. Since complete removal of OTA from foodstuffs is not feasible, additional strategies that may facilitate the reduction in OTA in food, such as adding baking soda and sugars, was also discussed, so that the industry may understand and apply practical measures to ensure the safety of its products destined for human consumption.

Bio-control on the contamination of Ochratoxin A in food: Current research and future prospects

Ochratoxin A (OTA) is a secondary metabolite of several fungi and widely exists in various species of foods. The establishment of effective methods for OTA reduction is a key measure to ensure food processing and human health. This article reviews the current research of OTA reduction by biological approaches, summarizes the characteristics and efficiency of them, and evaluates the transformation pathways and metabolites safety of each degradation technology. The shortcomings of various methods are pointed out and future prospects are also proposed. Biological methods are the most promising approaches for OTA control. The defect of them is the long processing time and the growth of microbial cells may affect the product quality. Therefore, the control of OTA contamination should be conducted according to the food processing and their product types. Besides, it is significant for the exploitation of new strains, enzyme and novel adsorbents.

Factors during Production of Cereal-Derived Feed That Influence Mycotoxin Contents

Mycotoxins are naturally present in cereal-based feed materials; however, due to adverse effects on animal health, their presence in derived animal feed should be minimized. A systematic literature search was conducted to obtain an overview of all factors from harvest onwards influencing the presence and concentration of mycotoxins in cereal-based feeds. The feed production processes covered included the harvest time, post-harvest practices (drying, cleaning, storage), and processing (milling, mixing with mycotoxin binders, extrusion cooking, ensiling). Delayed harvest supports the production of multiple mycotoxins. The way feed materials are dried after harvest influences the concentration of mycotoxins therein. Applying fungicides on the feed materials after harvest as well as cleaning and sorting can lower the concentration of mycotoxins. During milling, mycotoxins might be redistributed in cereal feed materials and fractions thereof. It is important to know which parts of the cereals are used for feed production and whether or not mycotoxins predominantly accumulate in these fractions. For feed production, mostly the milling fractions with outer parts of cereals, such as bran and shorts, are used, in which mycotoxins concentrate during processing. Wet-milling of grains can lower the mycotoxin content in these parts of the grain. However, this is typically accompanied by translocation of mycotoxins to the liquid fractions, which might be added to by-products used as feed. Mycotoxin binders can be added during mixing of feed materials. Although binders do not remove mycotoxins from the feed, the mycotoxins become less bioavailable to the animal and, in the case of food-producing animals, to the consumer, lowering the adverse effects of mycotoxins. The effect of extruding cereal feed materials is dependent on several factors, but in principle, mycotoxin contents are decreased after extrusion cooking. The results on ensiling are not uniform; however, most of the data show that mycotoxin production is supported during ensiling when oxygen can enter this process. Overall, the results of the literature review suggest that factors preventing mycotoxin production have greater impact than factors lowering the mycotoxin contents already present in feed materials.

Key Global Actions for Mycotoxin Management in Wheat and Other Small Grains

Mycotoxins in small grains are a significant and long-standing problem. These contaminants may be produced by members of several fungal genera, including Alternaria, Aspergillus, Fusarium, Claviceps, and Penicillium. Interventions that limit contamination can be made both pre-harvest and post-harvest. Many problems and strategies to control them and the toxins they produce are similar regardless of the location at which they are employed, while others are more common in some areas than in others. Increased knowledge of host-plant resistance, better agronomic methods, improved fungicide management, and better storage strategies all have application on a global basis. We summarize the major pre- and post-harvest control strategies currently in use. In the area of pre-harvest, these include resistant host lines, fungicides and their application guided by epidemiological models, and multiple cultural practices. In the area of post-harvest, drying, storage, cleaning and sorting, and some end-product processes were the most important at the global level. We also employed the Nominal Group discussion technique to identify and prioritize potential steps forward and to reduce problems associated with human and animal consumption of these grains. Identifying existing and potentially novel mechanisms to effectively manage mycotoxin problems in these grains is essential to ensure the safety of humans and domesticated animals that consume these grains.

Impact of experimental thermal processing of artificially contaminated pea products on ochratoxin A and phomopsin A

Fungi of Aspergillus and Penicillium genus can infect peas (Pisum sativum), leading to a contamination with the nephrotoxic and carcinogenic ochratoxin A (OTA). Under unfavourable conditions, a fungus primarily found on lupines, Diapothe toxica, may also grow on peas and produce the hepatotoxic phomopsin A (PHOA). To study the effect of processing on OTA and PHOA content, two model products-wheat/rye-mixed bread with pea flour addition and pea pasta-were manufactured at small-business scale from artificially contaminated pea flour. The decrease of OTA and PHOA contents were monitored along the production process as indicators for toxin transformation. Pea bread dough was subjected to proofing for 30-40 min at 32 °C and baked at 250 °C to 230 °C for 40 min. OTA content (LODs < 0.1 μg/kg) showed a reduction in the bread crust (initially 17.0 μg/kg) to 88% and no reduction in the crumb (110%). For PHOA (LODs < 3.6 μg/kg), a decrease to approximately 21% occurred in the bread crust (initially 12.5 μg/kg), whilst for crumb, a less intense decrease to 91% was found. Pea pasta prepared with two toxin levels was extruded at room temperature, dried and cooked for 8 min in boiling water. In pea pasta, OTA was reduced from 29.8 to 13.9 μg/kg by 22% each after cooking, whilst 15% and 10% of the initial toxin amounts were found in the cooking water, respectively. For PHOA, 60% and 78% of initially 14.3 μg/kg and 7.21 μg/kg remained in the cooked pasta. As only the decrease of the initial content was measured and no specific degradation products could be detected, further research is needed to characterise potential transformation products. Heat treatment reduces the initial PHOA content stronger than the OTA content during pasta cooking and bread making. However, significant amounts of both toxins would remain in the final products.

The Fate of Mycotoxins During the Processing of Wheat for Human Consumption

Mycotoxins are a potential health threat in cereals including wheat. In the European Union (EU), mycotoxin maximum levels are laid down for cereal raw materials and final food products. For wheat and wheat-based products, the EU maximum levels apply to deoxynivalenol (DON), zearalenone, aflatoxins, and ochratoxin A. This review provides a comprehensive overview on the different mycotoxins and their legal limits and on how processing of wheat can affect such contaminants, from raw material to highly processed final products, based on relevant scientific studies published in the literature. The potential compliance with EU maximum levels is discussed. Of the four mycotoxins regulated in wheat-based foods in the EU, most data are available for DON, whereas aflatoxins were rarely studied in the processing of wheat. Furthermore, available data on the effect of processing are outlined for mycotoxins not regulated by EU law-including modified and emerging mycotoxins-and which cover DON derivatives (DON-3-glucoside, mono-acetyl-DONs, norDONs, deepoxy-DON), nivalenol, T-2 and HT-2 toxins, enniatins, beauvericin, moniliformin, and fumonisins. The processing steps addressed in this review cover primary processing (premilling and milling operations) and secondary processing procedures (such as fermentation and thermal treatments). A special focus is on the production of baked goods, and processing factors for DON in wheat bread production were estimated. For wheat milling products derived from the endosperm and for white bread, compliance with legal requirements seems to be mostly achievable when applying good practices. In the case of wholemeal products, bran-enriched products, or high-cereal low-moisture bakery products, this appears to be challenging and improved technology and/or selection of high-quality raw materials would be required.

Ochratoxin A in food and urine: a nationwide Portuguese two-year study

Several toxic effects have been described after exposure to ochratoxin A (OTA), which can enter the human diet directly through food or through animal products via carry-over from contaminated feed. To assess the exposure of the Portuguese population to OTA, a study over a two-year period was conducted. It involved analysis of 472 morning urine samples from inhabitants of four regions, together with a survey of regional bread (738) and pork (254) samples. These foodstuffs are two staple foods in the Portuguese and Mediterranean diet that present a high and widespread consumption by the majority of the population. The bread samples analysed showed a low level of contamination, although the contamination range was broad and some of the samples exceeded the maximum level established in the European Union. Maize bread (broa), especially when made by mixing with rye, was the most contaminated, followed by whole grain-, rye- and wheat-based bread. However, the latter contributed more to OTA exposure, because they were more commonly consumed. Even though the occurrence was rather low, the average OTA amount in pork was relatively high compared to previous national and other surveys. The observed high within-subject variability of OTA in urine limited the use of this biomarker of exposure at the individual level, but not on a population or subgroup of subjects scale. Among the studied population, a widespread exposure was confirmed by the high frequency of OTA contamination in urine, although characterised by a low average contamination level. Independent of region or population, pork appears to be the main contributor to the daily OTA intake in Portugal. These data were clearly in contrast with previous studies showing that cereals and their derived products were the major contributors, while food of animal origin only contributed a small part to the total human dietary OTA exposure.

Ochratoxin A levels in spices and dried nuts consumed in Tunisia

A total of 112 samples of spices (24 caraway, 20 coriander, 25 curcuma, 20 black pepper and 23 red pepper) and 110 samples of dried nuts (44 almonds, 42 peanuts and 24 pistachio) purchased from popular markets in 24 regions of Tunisia were analyzed for ochratoxin A (OTA) by fluorescence HPLC. The average levels of contamination of OTA found in spice samples were 244, 206, 290, 274 and 203 µg/kg, respectively, for caraway, coriander, curcuma, black pepper and red pepper. Concerning dried nut samples, the average levels were 61, 60 and 89 µg/kg, respectively, for almonds, peanuts and pistachio. Contamination levels were higher than the usual norms (10.0 OTA µg/kg) established by the European Commission in 2005 . This survey is the first to be carried out on the natural occurrence of OTA in the main spices and dried nuts consumed by the Tunisian population.

Effects of processing on mycotoxin stability in cereals

The mycotoxins that generally occur in cereals and other products are not completely destroyed during food-processing operations and can contaminate finished processed foods. The mycotoxins most usually associated with cereal grains are aflatoxins, ochratoxins, deoxynivalenol, zearalenone and fumonisins. The various food processes that may have effects on mycotoxins include cleaning, milling, brewing, cooking, baking, frying, roasting, flaking, alkaline cooking, nixtamalization, and extrusion. Most of the food processes have variable effects on mycotoxins, with those that utilize high temperatures having the greatest effects. In general, the processes reduce mycotoxin concentrations significantly, but do not eliminate them completely. This review focuses on the effects of various thermal treatments on mycotoxins.

Considerations in the preparation of laboratory samples for the analysis of ochratoxin A in wheat

A process used to prepare the test portion of ground wheat from the whole grain laboratory sample for ochratoxin A (OTA) analysis using dry comminution with homogenisation and sub-sampling via a rotary sample divider was developed and evaluated. With respect to OTA content, the developed process produced a homogeneous sample of ground wheat from 10 kg of whole grain. Relative standard deviations of the mean OTA concentration for five naturally contaminated wheat samples processed using the developed method ranged from 9% to 19% over a relevant concentration range of 1.7 to 7.6 mg/kg. Additional studies demonstrated that OTA was stable in ground wheat with moisture content between 12 to 13% for at least a year when stored at ambient temperatures. Further examination of the developed comminution and dividing procedure demonstrated that higher concentrations were measured in smaller sized particles, indicating that the accuracy and precision of OTA analyses could be affected by the particle size of ground wheat.

Chemical, physical and biological approaches to prevent ochratoxin induced toxicoses in humans and animals

Ochratoxins are polyketide derived fungal secondary metabolites with nephrotoxic, immunosuppressive, teratogenic, and carcinogenic properties. Ochratoxin-producing fungi may contaminate agricultural products in the field (preharvest spoilage), during storage (postharvest spoilage), or during processing. Ochratoxin contamination of foods and feeds poses a serious health hazard to animals and humans. Several strategies have been investigated for lowering the ochratoxin content in agricultural products. These strategies can be classified into three main categories: prevention of ochratoxin contamination, decontamination or detoxification of foods contaminated with ochratoxins, and inhibition of the absorption of consumed ochratoxins in the gastrointestinal tract. This paper gives an overview of the strategies that are promising with regard to lowering the ochratoxin burden of animals and humans.

Fate of ochratoxin A in the processing of whole wheat grains during milling and bread production

Batches of whole wheat contaminated with ochratoxin A were produced by inoculation with Penicillium verrucosum under controlled conditions in the laboratory. The fate of ochratoxin was followed through initial cleaning, abrasive scouring of the outer grain coat, milling into wholemeal wheat or into 10 milled fractions. Bread was baked from both wholemeal flour and straight-run white flour. Concentrations of ochratoxin A in the cleanings, scourings, and the bran and offal fractions were increased, but reduced in the white flour. Scouring removed up to 44% of the ochratoxin A present, but only a small further loss occurred in the bread-making process. An overall reduction of about 75% could be achieved in white bread using a combination of cleaning scouring and removal of the bran and offal fractions. Maximum overall reduction in producing wholemeal bread was about 40%. The reduction in ochratoxin A that can be achieved must be considered in relation to economic constraints concerning the disposal of wasted grain. Appropriate strategies for the use or disposal of potentially highly contaminated cleanings, scourings, bran or offal must be established.

A review on ochratoxin A occurrence and effects of processing of cereal and cereal derived food products

Ochratoxin A (OTA) continues to grab global attention and concern for the hazard and impact that embody for both human and animals, based on its toxicity and occurrence. Despite OTA has been described in a myriad of foodstuffs, cereal and its derivatives remain the major contributors to OTA exposure. For that reason, a critical review on OTA occurrence reported by recent studies worldwide focusing on unprocessed and processed cereal foodstuffs is made in this work. Special attention is drawn to the major cereal derived products, namely flour, bread, breakfast cereals, baby/infant foods and the inherently involved technological food processing methods and its influence on the redistribution and chemical modification of OTA. The paper further examines the factors that influence the OTA content of cereal and its derived products, explicitly the different ecological niches of the ochratoxigenic mycobiota -Aspergillus spp. and Penicillium verrucosum, the agricultural practice involved, harvest procedures and storage conditions, the type of grain, and the nature and extent of technological processing as well as the ultimate stages of analytical quality level of the sampling and analysis of the suspected ingredients or foods.

Comparison of off- and in-line solid-phase extraction for enhancing sensitivity in capillary electrophoresis using ochratoxin as a model compound

This paper proposes and compares two approaches based on off- and in-line solid-phase extraction (SPE), intended to enhance sensitivity in capillary electrophoresis with ultraviolet detection (CE-UV) using as a model the determination of ochratoxin A (OA) in river water samples. In the off-line SPE mode, the reversed-phase sorbent (octadecilsylane, C(18)) selectively retains the target analyte (OA) and allows large volumes of the sample (70 mL) to be introduced and subsequently eluted in a small volume (0.1 mL) of an appropriate solution. In the in-line SPE mode, a custom-made microcartridge is inserted near the inlet of the capillary, which is filled with the same C(18) sorbent. This solid phase selectively retains OA present in a sample volume as low as approximately 640 microL for subsequent elution with ca. 135 nL of an appropriate eluent. The limit of detection (LOD) obtained with the in-line SPE method was 1 ng L(-1), which is 3 orders of magnitude lower than that obtained with CE-UV and roughly 1 order lower than that provided by the off-line SPE-CE-UV method.

Combined use of supported liquid membrane and solid-phase extraction to enhance selectivity and sensitivity in capillary electrophoresis for the determination of ochratoxin A in wine

This paper proposes a novel strategy to enhance selectivity and sensitivity in CE, using supported liquid membrane (SLM) and off-line SPE simultaneously. The determination of ochratoxin A (OA) in wine has been used to demonstrate the potential of this methodology. In the SLM step, the donor phase (either a 20 mL volume of a standard solution at pH 1 or a wine sample at pH 8) was placed in a vial, where a micromembrane extraction unit accommodating the acceptor phase (1 mL water, pH 11) in its lumen was immersed. The SLM was constructed by impregnating a porous Fluoropore Teflon (PTFE) membrane with a water-immiscible organic solvent (octanol). In the off-line SPE step, the nonpolar sorbent (C-18, 4 mg) selectively retained the target ochratoxin, enabling small volumes of acceptor phase (1 mL) to be introduced. The captured analytes were eluted in a small volume of methanol (0.1 mL). This procedure resulted in sample cleanup and concentration enhancement. The method was evaluated for accuracy and precision, and its RSD found to be 5%. The LODs for OA in the standard solutions and wine samples were 0.5 and 30 microg/L, respectively. The results obtained demonstrate that SLM combined with off-line is a good alternative to the use of immunoaffinity columns prior to CE analysis.

Dietary intake of ochratoxin A from conventional and organic bread

Ochratoxin A (OTA) was extracted from 100 bread samples by using accelerated solvent extraction (ASE) and analyzed with liquid chromatography coupled with fluorescence detection. The presence of OTA was confirmed by methyl-ester derivatization. Bread samples were bought from different bakeries and supermarkets, 74 of non-organic and 26 of organic bread. The incidence of OTA varied between 20.3% and 23.0% for non-organic and organic bread, respectively. The highest values were obtained with non-organic versus organic products, five samples exceeded the European maximum permitted limit of OTA (3 ng/g) for this product. Estimated daily intake of OTA in this study was 1.6 ng/kg b.w./day. This value represents 32% and 10% of the tolerable daily intake (TDI) according to the Scientific Committee on Food of the European Commission and the FAO/WHO Committee of Experts on Food Additives, respectively. The daily intake estimated from this study reflects the necessity to take a vigilant attitude to guarantee food safety.

Distribution of total aflatoxins in milled fractions of hulled rice

Two varieties of hulled rice artificially contaminated with aflatoxins at five different levels were processed by dehulling and polishing methods. Contamination levels ranged from 356 to 818 microg/kg and from 244 to 645 microg/kg in medium and long grain rice, respectively. After physical processing, four different milled fractions were obtained (hull, bran, polished broken grains, and polished whole kernels). The fractions were analyzed for total aflatoxins (B1, B2, G1, and G2) by enzyme-linked immunosorbent assay (ELISA). Aflatoxins were removed in fractions intended for human consumption (polished broken grains and polished whole kernels) at rates up to 97%. They were found throughout all fractions, but higher contamination levels were detected in hull and bran fractions than in unprocessed kernels and polished fractions. Regardless of the rice variety, the aflatoxin distribution pattern depended on the initial contamination level and type of milled fraction but not on the duration of polishing.

Prevention of ochratoxin A in commodities and likely effects of processing fractionation and animal feeds

Whenever possible, preventing the formation of ochratoxin A (OTA) in susceptible food commodities such as cereals, grapes and coffee beans should be the primary aim. Each product tends to host a specific OTA-producing mould so that the environmental conditions and factors that encourage the subsequent formation of OTA need to be understood. Codes of Practice for prevention and management of OTA are being developed and can be used in conjunction with a HACCP approach to protect the end consumer, in line with EU statutory limits. If prevention fails, an understanding of how concentrations change during the whole food chain may be useful in minimizing the concentrations reaching the consumer. OTA is quite heat stable under neutral conditions but may be partly broken down, e.g. in extrusion processing. In milling or other separation procedures, OTA will be concentrated or reduced in the resulting components. By-products such as 'cleanings' or bran may contain high concentrations and are often used for animal feed. Introduction of guideline or statutory maximum concentrations for feed within the EU makes it essential that concentrations of ochratoxin A in such by-products are acceptable. This paper reviews recent literature and findings from recent 5th Framework EU-funded projects.

Penicillium verrucosum occurrence and ochratoxin A contents in organically cultivated grain with special reference to ancient wheat types and drying practice

This study addresses the relationship between the ochratoxigenic strains of Penicillium verrucosum and ochratoxin A (OTA) contents in organically cultivated grain. It included 37 combined, non-dried grain samples from farmers with no drying facilities as well as 19 non-dried and 22 dried samples from six farms with on-farm drying facilities (Case studies 1-6). The study focused on the ancient wheat type spelt but also included samples of wheat, rye, barley, oats, triticale, emmer, and einkorn. All 78 samples were analysed for moisture content (MC) and occurrence of P. verrucosum. The latter was assessed by plating non-disinfected kernels on DYSG agar and counting those contaminated by the fungus. Fifty-five samples were analysed for OTA. Most of the combine harvested samples (82%) were contaminated with P. verrucosum prior to drying. This was ascribed to difficult harvest conditions and many samples of spelt, which was significantly more contaminated by P. verrucosum than oats, wheat and barley. Though not statistically significant, the results also indicated that spelt was more contaminated than rye, which is usually regarded the most sensitive small grain cereal. No correlation was found between number of kernels contaminated by P. verrucosum and OTA content. Despite many non-dried samples being contaminated by P. verrucosum, only two exceeded the EU maximum limit for grain (5 ng OTA g(-1)), both being spring spelt with 18 and 92 ng g(-1), respectively. The problems were most likely correlated to a late harvest and high MC of the grain. The case studies showed exceedings of the maximum limit in a batch of dried oats and spring wheat, respectively, probably to be explained by insufficient drying of late harvested grain with high MC. Furthermore, our results clearly indicate that OTA is not produced in significant amounts in samples with MCs below 17%. All dried samples with MCs above 18% exceeded the 5 ng OTA g(-1) limit in grain. However, no correlation between MC and the amount of OTA produced was found.

Analysis of ochratoxin A in foods consumed by inhabitants from an area with balkan endemic nephropathy: a 1 month follow-up study

In the 1950s, a series of publications from Bulgaria, Yugoslavia, and Romania locally described a kidney disease called Balkan Endemic Nephropathy (BEN). In Bulgaria, the exposure of populations to ochratoxin A (OTA) was supported by analysis of individual food items demonstrating a higher prevalence and higher levels of OTA in food from the high-incidence areas of BEN. In this work, food consumption from a series of individuals from two villages of the BEN area during 1 month was followed using the duplicate diet method. Meals consumed by volunteers from both villages showed uneven OTA contents, spreading from below the limit of quantification (<0.07 microg/kg) to 2.6 microg/kg. The average weekly intake of OTA varies from 1.86 to 92.7 ng/kg of body weight. Some of these levels approach the provisional tolerable weekly intake (PTWI) established by the JECFA at 100 ng/kg of body weight. These results confirm previous studies performed in the same area and demonstrate the high exposure of this population to OTA, thus strengthening the hypothesis of the involvement of this mycotoxin in BEN etiology.

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

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

Fungi: toxic killers or unavoidable nuisances?

OBJECTIVES

This discussion is focused on the many roles of fungi in human health, and also to put the mycotoxin literature into perspective.

DATA SOURCES

Data are derived from the literature referenced in PubMed from the National Library of Medicine, earlier references in the authors' reprint collection, and ongoing research. Studies for review were either selected from the peer-reviewed literature or from standard texts that are well recognized in the field.

RESULTS

The review yielded many studies of the role of fungi in allergic disease, but none that systematically documented such a role for mycotoxins or fungal volatiles. Many case studies were found, but none of these unequivocally document a cause/effect relationship between mycotoxin exposure by inhalation and human disease in residential, school, or office settings.

CONCLUSIONS

The review led to the conclusion that that the primary result from fungal exposure is allergic disease, and that the evidence for inhalation disease resulting from mycotoxin exposure in residential and office settings is extremely weak.

Evaluation of mycotoxin-contaminated cereals for their use in animal feeds in Hungary

In the period between December 5, 1991 and September 17, 1998, 760 maize, 367 wheat, 119 soybean, 222 barley, 85 bran, 32 triticale, 60 oat, 14 rye and 22 sunflower samples were investigated for the presence and concentration of seven fusariotoxins (T-2 toxin, zearalenone, deoxynivalenol, nivalenol, diacetoxyscirpenol, HT-2 toxin, fusarenone-X) and OTA. The comparison of analytical data with those of the relevant literature revealed that although the incidence rate and/or concentration of Fusarium mycotoxins and OTA in Hungarian-grown cereals is occasionally considerable, the position of the country is not worse that the average of countries. Our findings indicate that soybean tends to be good substrate for trichothecene-producing fungi and the rate of contamination is regarded as substantial. The commodities were assorted into one of three quality categories. The proportion of objectionable samples was only 3.0, 2.2, 2.3 and 1.7% in maize, wheat, barley and soybean samples, respectively. However, this low rate of objection might still be a source of great economic loss. The proportion of objectionable samples was much higher in the case of bran, oat and triticale (7.1, 6.7, and 6.3%, respectively). The results of the present investigation indicate a need for regular screening for mycotoxins of importance and individual appraisal of each commodity from the point of their use in animal feeds.

Solid-phase extraction applied to the determination of ochratoxin A in wines by reversed-phase high-performance liquid chromatography

A reversed-phase high-performance liquid chromatographic method is described for the analysis of Ochratoxin A at low microg l(-1) levels in samples of artificially contaminated wines. The method involves solid-phase extraction of samples using octadecylsilane cartridges and an additional preconcentration step prior to chromatography with isocratic elution and fluorimetric detection. The method was evaluated for accuracy and precision with relative standard deviations lower than 10%. Recoveries of ochratoxin A added to commercial wines over the range 0.1-3.0 microg l(-1) were higher than 80% in the assays. The performance of the octadecylsilane cartridge method tested compared very favourably with results of other published studies of ochratoxin A which use immunoaffinity columns or solvent extraction techniques.

Use of various clean-up procedures for the analysis of ochratoxin A in cereals

A rapid and reliable procedure has been developed for the determination of ochratoxin A in wheat and oats. The method consists of extraction of the sample with acidic chloroform, followed by defatting with n-hexane and finally, HPLC determination with fluorometric detection. Mean recoveries for wheat and oats spiked at levels between 1 and 100 micrograms/kg ranged from 80 to 104%. The limit of determination (field blank +6 sigma) was 0.8 micrograms/kg and the precision (within-laboratory relative standard deviation) ranged from 3 to 7%. The method was tested on 34 wheat and 34 oats samples. Ochratoxin A was confirmed in some positive samples by methyl ester formation and/or by clean-up of the extracts with immunoaffinity columns. The method was not appropriate for the analysis of barley (45 tested samples), rye (69 samples) or trout feed (13 samples). A false positive was recorded within the four positive barley samples and 18 false positives were recorded within the 21 positive rye samples whereas trout feed samples could not be analysed due to insufficient clean-up. The use of immunoaffinity columns made the analysis of trout feed and rye samples possible, providing excellent clean-up of the extracts with no false positive results and a good limit of determination (0.2 micrograms/kg).