[Determination of ochratoxin A in human milk]

Infant nutrition at risk: a global systematic review of ochratoxin A in human breast milk-human health risk assessment

Human breast milk is the optimal source of nutrition for newborns, but the potential transfer of contaminants like mycotoxins, particularly ochratoxin A (OTA), from maternal blood to milk remains a concern. This systematic review aims to provide a comprehensive analysis of global OTA levels in human breast milk and assess the associated health risks. We conducted a thorough search of scientific databases, including Web of Science, ScienceDirect, Scopus, Google Scholar and PubMed, using keywords related to OTA in human breast milk. A total of 39 studies met the inclusion criteria for this review. OTA levels compared to limits, estimated infant intake at various ages and health risks assessed using Margin of Exposures (MOEs) and Hazard quotient (HQ). Our findings reveal the widespread presence of OTA in breast milk across different regions, with notably higher levels detected in Africa compared to Asia, South America and Europe. The higher concentrations observed in warmer, humid climates suggest that environmental factors significantly influence OTA contamination. Mature breast milk samples generally exhibited greater OTA exposure. The neoplastic and non-neoplastic effects demonstrate generally low risks globally. The regional differences in OTA levels and associated health risk assessments underscore the need for continued research into the health impacts of OTA exposure in infants. This includes further investigation into multiple sources of exposure, such as infant formula, within the broader context of the exposome framework.

Occurrence of ochratoxin A in breast milk and urine samples of nursing mothers in Bangladesh

The mycotoxin ochratoxin A (OTA) is a potent nephrotoxin with carcinogenic properties and, thus, of concern as a food contaminant. Since food contaminant data are scarce in Bangladesh, we applied human biomonitoring to gain more insights into OTA exposure in the country's population. OTA concentrations in human milk and urine samples of nursing mothers were determined with the aim to assess also exposure to this mycotoxin in breastfed infants. Breastfeeding mothers (n = 74) from three districts of Bangladesh (Sylhet, Cumilla, and Mymensingh region) participated in this study. They provided demographic data, along with breast milk and urine samples. OTA levels were measured by a competitive enzyme-linked immunosorbent assay (ELISA) with a detection limit of 60 ng/L for milk and 30 ng/L for urine.OTA was detected in 62.2% of all breast milk samples (mean 74.8 ± 49.0 ng/L, range < LOD-243.3 ng/L) and in 51.4% of all urine samples (mean 44.3 ± 63.5 ng/L, range < LOD-519.3 ng/L). The differences observed between regions for mean breast milk or for urinary OTA levels were relatively small. No significant correlation was observed between OTA levels in breast milk and food consumption patterns among nursing mothers. Regarding infant exposure, the estimated average daily intake of OTA for all was 15.0 ng/kg bw/day (range 4.5-45 ng/kg bw/day). In 34.5% of these infants, their estimated daily OTA intake exceeded a preliminary TDI value set by EFSA (17 ng/kg bw/day). The mean OTA intake was slightly higher (16.2 ± 7.8 ng/kg bw/day) in 1-2 months babies than in older infants (< 2 to 12 months), although the difference was not significant. Presence of OTA in most milk and urine samples of nursing mothers documents their widespread dietary mycotoxin exposure. Although based on a relatively small number of participants, the present analysis indicates non-negligible exposure of some nursed infants in Bangladesh. Therefore, further biomonitoring studies and investigations on major sources of OTA in food commodities are encouraged.

Ochratoxin A affects oocyte maturation and subsequent embryo developmental dynamics in the juvenile sheep model

The genotoxic and nephrotoxic mycotoxin Ochratoxin A (OTA) has also been reported to have adverse effects on oocyte maturation and embryo development. Previous studies on the effects of OTA on female fertility have used micromolar concentrations, but no information is available to date on effects in a more relevant nanomolar range. This study used a juvenile sheep model to evaluate the effects of oocyte exposure to low levels of OTA on maturation, fertilization, and embryo development. Further, it was investigated whether different mechanisms of action of OTA could be responsible for varying toxic effects at different levels of exposure. Cumulus-oocyte-complexes (COCs) were exposed to 10 μmol/L-0.1 nmol/L OTA during in vitro maturation and evaluated for cumulus viability, oocyte maturation, and bioenergetic/oxidative status. COCs were subjected to in vitro fertilization, embryo culture, and embryo quality assessment via morphology, viability, bioenergetic/oxidative status, and time-lapse monitoring. At micromolar concentrations, OTA induced cytotoxic effects, by reducing cumulus expansion and oocyte maturation. OTA altered temporospatial dynamics of zygote pronuclear formation and embryo morphokinetics. Blastocysts, even morphologically normal, were found to undergo collapse events, which were probably related to boosted blastocyst mitochondrial activity. At nanomolar concentrations, OTA did not affect COC morpho-functional parameters, but impaired oocyte ability to prevent polyspermy and increased blastocyst apoptosis. In conclusion, in the female germ cell, cytotoxic nonspecific effects characterize OTA-induced toxicity at high exposure levels, whereas fine tuning-mode effects, not associated with altered cell viability and integrity, characterize OTA toxic action at low levels.

Ochratoxin A: 50 Years of Research

Since ochratoxin A (OTA) was discovered, it has been ubiquitous as a natural contaminant of moldy food and feed. The multiple toxic effects of OTA are a real threat for human beings and animal health. For example, OTA can cause porcine nephropathy but can also damage poultries. Humans exposed to OTA can develop (notably by inhalation in the development of acute renal failure within 24 h) a range of chronic disorders such as upper urothelial carcinoma. OTA plays the main role in the pathogenesis of some renal diseases including Balkan endemic nephropathy, kidney tumors occurring in certain endemic regions of the Balkan Peninsula, and chronic interstitial nephropathy occurring in Northern African countries and likely in other parts of the world. OTA leads to DNA adduct formation, which is known for its genotoxicity and carcinogenicity. The present article discusses how renal carcinogenicity and nephrotoxicity cause both oxidative stress and direct genotoxicity. Careful analyses of the data show that OTA carcinogenic effects are due to combined direct and indirect mechanisms (e.g., genotoxicity, oxidative stress, epigenetic factors). Altogether this provides strong evidence that OTA carcinogenicity can also occur in humans.

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

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

Prevalence of ochratoxin a in human milk in the khorrambid town, fars province, South of iran

BACKGROUND

Ochratoxins belong to a group of mycotoxins produced as the secondary metabolites by filamentous fungi, such as Aspergillus and Penicillium. These toxins may be teratogenic, mutagenic, hepatotoxic, nephrotoxic, and may have immunosuppressive effects and pose a serious health problems to exposed humans and animals.

OBJECTIVES

The present study aimed to determine the level of ochratoxin A (OTA) in the samples of mothers' milk in the Khorrambid Town, Fars Province, south of Iran.

MATERIALS AND METHODS

Between June and July 2011, samples of human milk were obtained from 87 mothers. The samples were diluted by absolute methanol at 1:4 ratio and after centrifugation, the supernatant was directly used to determine the level of OTA using competitive enzyme-linked immunosorbent assay (ELISA).

RESULTS

Among 87 human milk samples, 84 (96.6%) samples had positive results for OTA at a mean level of 24.57 ± 13.6 ng/L. According to the European Union Standard, 14 (16%) positive samples revealed more than the maximum limit of 40 ng/L for ochratoxin (range, 1.6-60 ng/L).

CONCLUSIONS

Presence of OTA in the milk of mothers denotes a probable consumption of a contaminated foods. Therefore, regular monitoring of foods for presence of mycotoxins for lactating mothers seems necessary.

Ochratoxin A: developmental and reproductive toxicity-an overview

Ochratoxin A (OTA) is nephrotoxic, hepatotoxic, reprotoxic, embryotoxic, teratogenic, neurotoxic, immunotoxic, and carcinogenic for laboratory and farm animals. Male and female reproductive health has deteriorated in many countries during the last few decades. A number of toxins in environment are suspected to affect reproductive system in male and female. OTA is one of them. OTA has been found to be teratogenic in several animal models including rat, mouse, hamster, quail, and chick, with reduced birth weight and craniofacial abnormalities being the most common signs. The presence of OTA also results in congenital defects in the fetus. Neither the potential of OTA to cause malformations in human nor its teratogenic mode of action is known. Exposure to OTA leads to increased embryo lethality manifested as resorptions or dead fetuses. The mechanism of OTA transfer across human placenta (e.g., which transporters are involved in the transfer mechanism) is not fully understood. Some of the toxic effects of OTA are potentiated by other mycotoxins or other contaminants. Therefore, OTA exposure of pregnant women should be minimized. OTA has been shown to be an endocrine disruptor and a reproductive toxicant, with abilities of altering sperm quality. Other studies have shown that OTA is a testicular toxin in animals. Thus, OTA is a biologically plausible cause of testicular cancer in man.

Ochratoxin A exposure biomarkers in the Czech Republic and comparison with foreign countries

Among ochratoxins, ochratoxin A (OTA) occupies a dominant place and represents significant risk for human and animal health which also implies economic losses around the world. OTA is nephrotoxic, hepatotoxic, teratogenic and immunotoxic mycotoxin. OTA exposure may lead to formation of DNA adducts resulting to genotoxicity and carcinogenicity (human carcinogen of 2B group). Now it seems that OTA could be "a complete carcinogen" which obliges to monitor its presence in biological materials, especially using the suitable biomarkers. In this article, OTA findings in urine, blood, serum, plasma and human kidneys (target dose) in the Czech Republic and comparison with foreign countries are presented.

Immunochemical methods for ochratoxin A detection: a review

The safety of food and feed depends to a great deal on quality control. Numerous compounds and organisms may contaminate food and feed commodities and thus pose a health risk for consumers. The compound of interest in this review is ochratoxin A (OTA), a secondary metabolite of the fungi Aspergillus and Penicillium. Due to its adverse health effects, detection and quantification are of utmost importance. Quality control of food and feed requires extraction and analysis, including TLC, HPLC, MS, and immunochemical methods. Each of these methods has its advantages and disadvantages. However, with regard to costs and rapidity, immunochemical methods have gained much interest in the last decade. In this review an introduction to immunochemistry and assay design will be given to elucidate the principles. Further, the application of the various formats to the detection and quantification of ochratoxin will be described, including the use of commercially available kits.

An aptamer-based chromatographic strip assay for sensitive toxin semi-quantitative detection

An aptamer-based chromatographic strip assay method for rapid toxin detection was developed. The aptamer-based strip assay was based on the competition for the aptamer between ochratoxin A and DNA probes. The sensing results indicated that the sensitivity of the aptamer-based strip was better than that of conventional antibody-based strips. The visual limit of detection of the strip for qualitative detection was 1 ng/mL while the LOD for semi-quantitative detection could down to 0.18 ng/mL by using scanning reader. The recoveries of test samples were from 96% to 110%. All detections could be achieved in less than 10 min, indicating that the aptamer-based strip could be a potential useful tool for rapid on-site detections.

The presence of ochratoxin A in cord serum and in human milk and its correspondence with maternal dietary habits

BACKGROUND

Ochratoxin A (OTA) is a mycotoxin present in food that can be found in human blood and milk.

PURPOSE

The link between the nutritional habits of pregnant women both of Italian and foreign nationality resident in Italy and the presence of ochratoxin A in cord blood and in maternal milk was investigated.

METHODS

The study involved 130 pregnant women. Food consumption during pregnancy was evaluated by means of the EPIC questionnaire; OTA content was determined in cord serum and maternal milk by HPLC.

RESULTS

The mean daily dietary intake of OTA was 1.02 ± 1.20 and 0.87 ± 0.78 ng/kg of bodyweight for Italian and non-Italian women, respectively, but this difference was not statistically significant. The incidence of positive milk samples was 73.0 and 85.0% among the Italian and non-Italian mothers, respectively. Pork meat, soft drinks, sweets and red wine showed a significant relationship with OTA level in serum. As far as milk is concerned, a positive relationship resulted for pork meat, sweets, soft drinks and seed oils. A positive relationship between serum OTA level and the ratio serum/milk OTA was found. The intake of OTA had no effect on the cord blood creatinine level.

CONCLUSIONS

This study confirms that OTA is widely present in human milk and therefore could pose a risk for the newborn.

Review. Ochratoxin A: Presence in Human Plasma and Intake Estimation

Ochratoxin A (OTA) is a fungal toxic secondary metabolite that can be found in several foodstuffs and thereby ingested by humans. One way to assess exposure of humans to OTA is the determination of the levels of this mycotoxin in blood plasma from a certain population. Such studies have been done in many countries, both in healthy people and nephropathy patients. Relationships with individual characteristics were investigated in several cases. Thus, most studies found no correlation with age, either with gender. However, the few studies that found correlation between OTA plasma levels and gender showed that men presented the highest values. When sampling was done over more than one season, the highest OTA plasma levels were found mostly in summer. Differences within regions of a country were related to dietary habits of each area. OTA levels of group populations showed variations from year to year, whereas intraindividual repetitions showed no specific trend. Daily intake of the toxin can be estimated from OTA plasma concentrations by the Klaassen equation. OTA toxicokinetics are considered in this review. Calculated daily intake of OTA by different studies did not overpass the proposed tolerable daily intakes of OTA.

Maternal dietary habits and mycotoxin occurrence in human mature milk

During 2006, 82 samples of human mature milk were collected at Italian hospitals and checked for aflatoxin M1 (AFM1) and ochratoxin A (OTA) by immunoaffinity column extraction and HPLC. AFM1 was detected in four (5%) of milk samples (ranging from < 7 ng/L to 140 ng/L; mean level: 55.35 ng/L); OTA was detected in 61 (74%) of milk samples (ranging from < 5 ng/L to 405 ng/L; mean level: 30.43 ng/L. OTA levels were significantly higher (p less, not double equals 0.05) in milk of habitual consumers of bread, bakery products and cured pork meat. No other statistically significant differences were observed although habitual consumers of pasta (p = 0.059), cookies (p = 0.061) and juices (p = 0.063) had mean contamination values of OTA higher than the moderate consumer. The very few AFB1 positive samples did not allow statistical comparisons. The present study confirms that the occurrence of OTA in human milk is related to maternal dietary habits. The findings support the possibility of dietary recommendations to woman, during pregnancy and lactation, aimed to tentatively reduce the OTA contamination of human milk.

Ochratoxin A: An overview on toxicity and carcinogenicity in animals and humans

Ochratoxin A (OTA) is a ubiquitous mycotoxin produced by fungi of improperly stored food products. OTA is nephrotoxic and is suspected of being the main etiological agent responsible for human Balkan endemic nephropathy (BEN) and associated urinary tract tumours. Striking similarities between OTA-induced porcine nephropathy in pigs and BEN in humans are observed. International Agency for Research on Cancer (IARC) has classified OTA as a possible human carcinogen (group 2B). Currently, the mode of carcinogenic action by OTA is unknown. OTA is genotoxic following oxidative metabolism. This activity is thought to play a central role in OTA-mediated carcinogenesis and may be divided into direct (covalent DNA adduction) and indirect (oxidative DNA damage) mechanisms of action. Evidence for a direct mode of genotoxicity has been derived from the sensitive 32P-postlabelling assay. OTA facilitates guanine-specific DNA adducts in vitro and in rat and pig kidney orally dosed, one adduct comigrates with a synthetic carbon (C)-bonded C8-dG OTA adduct standard. In this paper, our current understanding of OTA toxicity and carcinogenicity are reviewed. The available evidence suggests that OTA is a genotoxic carcinogen by induction of oxidative DNA lesions coupled with direct DNA adducts via quinone formation. This mechanism of action should be used to establish acceptable intake levels of OTA from human food sources.

Biomarkers of human exposure to ochratoxin A

Low blood serum/plasma concentrations of ochratoxin A (OTA) have been reported for healthy persons in more than 20 countries. Epidemiology studies in Bulgaria, Romania, Spain, the Czech Republic, Turkey, Italy, Egypt, Algeria and Tunisia have found significantly higher serum or plasma levels of OTA in patients with certain kidney disorders compared to healthy people, although the association may not be a causal one. Regional variations within one country, seasonal differences and variation within one person were found in some studies. Correlations with age and gender have not usually been detected. Detection limits using liquid chromatographic methods are about 0.02-0.1 ng ml(-1) plasma/serum so that incidences of positives often are 50-100%, reflecting widespread and continuous exposure of humans to OTA. In a study in the UK, OTA in urine was found to be a better indicator of OTA consumption than OTA in plasma. Nevertheless, blood plasma concentrations have been widely used to estimate dietary intake of OTA, using equations relating it with plasma concentration, plasma clearance and bioavailability. A further source of human exposure is airborne dust. OTA has been detected in human milk in several countries and comparisons with serum/blood levels have been made in Germany and Sweden.

Toxicokinetics and toxicodynamics of ochratoxin A, an update

Ochratoxin A (OTA) is a mycotoxin produced by fungi of two genera: Penicillium and Aspergillus. OTA has been shown to be nephrotoxic, hepatotoxic, teratogenic and immunotoxic to several species of animals and to cause kidney and liver tumours in mice and rats. Because of differences in the physiology of animal species, wide variations are seen in the toxicokinetic patterns of absorption, distribution and elimination of the toxin. Biotransformation of OTA has not been entirely elucidated. At present, data regarding OTA metabolism are controversial. Several metabolites have been characterized in vitro and/or in vivo, whereas other metabolites remain to be characterized. Several major mechanisms have been shown as involved in the toxicity of OTA: inhibition of protein synthesis, promotion of membrane peroxidation, disruption of calcium homeostasis, inhibition of mitochondrial respiration and DNA damage. The contribution of metabolites in OTA genotoxicity and carcinogenicity is still unclear. The genotoxic status of OTA is still controversial because contradictory results were obtained in various microbial and mammalian tests, notably regarding the formation of DNA adducts. More recent studies are focused on the OTA ability to disturb cellular signalling and regulation, to modulate physiological signals and thereby to influence cells viability and proliferation. The present paper offers an update on these different issues. In addition since humans and animals are likely to be simultaneously exposed to several mycotoxins, especially through their diet, the little information available on the combined effects of OTA and other mycotoxins has also been reviewed.

Aflatoxin M1and ochratoxin A in a human milk bank in the city of São Paulo, Brazil

Because infants are more susceptible to the adverse effects of mycotoxins, this work was carried out to determine aflatoxin M(1) (AFM(1)) and ochratoxin A (OA) in milk from the Human Milk Bank of the Southern Regional Hospital, São Paulo, Brazil. Analytical methods were first established and evaluated. The methods involved the extraction of AFM(1) with methanol and OA with 1% aqueous sodium bicarbonate solution and methanol, clean-up with immunoaffinity columns having antibodies specific for each mycotoxin and quantification by high performance liquid chromatography (HPLC) with fluorescence detection. The method established for AFM(1) had mean recovery percentages of 94, 77 and 82% and coefficients of variation of 17.5, 3.4 and 4.2% at 0.01, 0.03 and 0.05 ng ml(-1), respectively. For the OA method, the corresponding values were 84, 84 and 75% for recovery and 14.1, 3.7 and 4.0% for the coefficient of variation. The limit of quantification for both methods was 0.01 ng ml(-1). Of a total of 50 samples analysed, only one was contaminated with AFM1, at 0.024 ng ml(-1), and two with OA, at 0.011 and 0.024 ng ml(-1). Although the incidence observed was low, it is recommended that the study be extended to other milk banks of the city of São Paulo.

Ochratoxin A and human chronic nephropathy in Tunisia: is the situation endemic?

Ochratoxin A (OTA) is a nephrotoxic mycotoxin that is being increasingly considered as the main causal agent of Balkan endemic nephropathy (BEN), a fatal kidney disease associated with the end stage of urothelial tumours. However, despite the considerable amount of data, it is still controversial whether OTA plays a causative or only a subordinate role in the induction of this human nephropathy. Tunisia for years had to confront a very similar human nephropathy, which is tentatively called chronic interstitial nephropathy of unknown cause. This study tends firstly to consolidate the suspected link between this Tunisian chronic interstitial nephropathy (CIN) of unknown cause and the presence of OTA in the blood and food of such patients, and second to enlighten the endemic character of this particular nephropathy. Therefore, in four consecutive inquiries, performed within the period 1991-2000, blood and food OTA contaminations were assayed and compared for 954 nephropathy patients and 205 healthy subjects from the Tunisian general population. This survey was also designed to show that, although the whole population is likely to be exposed to OTA, specific people living in conditions showing similarities with the Balkans do have a kidney disease apparently linked to ochratoxin in food. The results showed that the highest incidences were found in patients with CIN of unknown cause. Indeed, the percentages of OTA-positive samples ranged from 93% to 100%, whereas it was only from 62% to 82% in healthy subjects. Mean OTA concentrations were also higher in patients with CIN of unknown cause than in controls (44.4 +/- 19 microg/L to 55.6 +/- 19 microg/L as opposed to 1.22 +/- 1.2 microg/L to 3.35 +/- 2.32 microg/L, respectively). This study emphasizes further the implication of OTA on this particular human nephropathy and underlines the probable causative role of OTA in the onset of this disease. It is important to note that the highest levels of food OTA contamination were found in the group presenting with CIN of unknown cause, indicating that, similar to the case in the Balkans, people are exposed to OTA essentially by their food.

Ochratoxin A concentrations in food and feed from a region with Balkan Endemic Nephropathy

Balkan Endemic Nephropathy (BEN), a chronic renal disease of unknown aetiology, is found in geographically close areas of Bulgaria, Romania, Serbia, Croatia, Bosnia and Herzegovina, Slovenia, and the former Yugoslav Republic of Macedonia. Ochratoxin A (OTA), a secondary metabolite of Aspergillus and Penicillium species and a natural contaminant of food and feed, is a putative cause of BEN. Some studies have found a geographic covariation between OTA content in food/feed and BEN manifestation; others have not. In May 2000, using a competitive direct ELISA assay for OTA (detection limit 1 microg kg(-1)), we investigated OTA contamination in 165 samples of home-produced food (beans, potatoes, corn, wheat, flour) and feed from households in villages from the BEN region (Vratza district) of north-western Bulgaria. Samples were collected from: (a) BEN villages (n = 8), and therein from BEN households (20), and BEN-free households (16) (within-village controls, WVC households); and (b) BEN-free villages (7) and therein BEN-free households (22) (between-village controls, BVC). BEN households consistently had a higher proportion of OTA-positive samples than WVC households, but similar (for some foods) or lower (for other foods) proportions to BVC households. The proportion of OTA-positive samples was also higher in BVC than in WVC households. Furthermore, BEN households had a similar proportion of OTA-positive samples to the pooled, WVC and BVC, group of households. OTA-exposure estimates, derived from our OTA-concentration findings and the reported average per capita monthly consumption of basic foods in rural Bulgaria, showed the highest OTA intake in BEN households (1.21 microg day(-1)), versus 1.03 microg day(-1) in BVC and 0.71 microg day(-1) in WVC households. These OTA intakes are higher than those in the EU, and are close to the upper limits acceptable to several food-safety organizations. The results indicate that OTA may not alone cause BEN; only synergistically with other environmental toxicants and/or predisposing genotypes may do so.

Human exposure to mycotoxins in Egypt

This investigation examined the exposure of Egyptian infants to Aflatoxin M1 (AfM1) and of lactating mothers to Aflatoxin B1, using AfM1 in human milk as a biomarker for exposure to AfB1. The presence of ochratoxin A (OA) in human milk was also investigated to determine the levels of infants exposure to OA from human milk. The results indicated that AfM1 was found in 66 (55 %) of 120 human milk samples with a mean of 0.3 ± 0.53 ng/mL (range 0.02 to 2.09 ng/mL). OA was found in 43 (35.8 %) of 120 human milk samples with a mean of 21.1 ± 13.7 ng/mL (range 5.07 to 45.01 ng/mL), which will cause a daily intake of OA from human milk exceeding the suggested tolerable dose of 5 ng/kg-1 of OA body weight. On the other side AfM1 was found in 25 % of blood samples (5 out of 20 samples), at a mean of 1.18 ng/mL, but it was detected only in one urine sample (1 out of 20 samples). OA was detected only in 2 out of 13 blood samples (15.4 %) with an average 3.67 ng/mL. Whereas OA was not detected in all analyzed urine samples.

Ochratoxin A in airborne dust and fungal conidia

Farm workers are often exposed to high concentrations of airborne organic dust and fungal conidia, especially when working with plant materials. The purpose of this investigation was to study the possibility of exposure to the mycotoxin ochratoxin A (OTA) through inhalation of organic dust and conidia. Dust and aerosol samples were collected from three local cowsheds. Aerosol samples for determination of total conidia and dust concentrations were collected by stationary sampling on polycarbonate filters. Total dust was analysed by gravimetry, and conidia were counted using scanning electron microscopy. A method was developed for extraction and determination of OTA in small samples of settled dust. OTA was extracted with a mixture of methanol, chloroform, HCl, and water, purified on immunoaffinity column, and analysed by ion-pair HPLC with fluorescence detection. Recovery of OTA from spiked dust samples (0.9-1.0 microg/kg) was 74% (quantitation limit 0.150 microg/kg). OTA was found in 6 out of 14 settled dust samples (0.2-70 microg/kg). The total concentration of airborne conidia ranged from < 1.1 x 10(4) to 3.9 x 15(5) per m3, and the airborne dust concentration ranged from 0.08 to 0.21 mg/m3. Conidia collected from cultures of Penicillium verrucosum and Aspergillus ochraceus contained 0.4-0.7 and 0.02-0.06 pg OTA per conidium, respectively. Testing of conidial extracts from these fungi in a Bacillus subtilis bioassay indicated the presence of toxic compounds in addition to OTA. The results show that airborne dust and fungal conidia can be sources of OTA. Peak exposures to airborne OTA may be significant, e.g., in agricultural environments.

Current importance of ochratoxin A-producing Aspergillus spp

Ochratoxin A (OA) is receiving attention worldwide because of the hazard it poses to human and animal health. OA contamination of commodities, such as cereals or pork and poultry meat, is well recognized. Nevertheless, there is an increasing number of articles reporting OA contamination in other food commodities, such as coffee, beer, wine, grape juice, and milk, in the last few years. This continuous and increasing exposure to OA that humans experience is reflected in the high incidence of OA in both human blood and milk in several countries. OA was believed to be produced only by Aspergillus ochraceus and closely related species of section Circumdati and by Penicillium verrucosum; however, in the genus Aspergillus, the production of OA has been recently reported by species outside the section Circumdati. Thus, it has been clearly established as a metabolite of different species of the section Nigri, such as Aspergillus niger and Aspergillus carbonarius. OA production ability by Aspergillus spp. is more widespread than previously thought; therefore, there is the possibility that unexpected species can be new sources of this mycotoxin in their natural substrates.

Presence of ochratoxin A in human milk in relation to dietary intake

Individual and geographical variations in ochratoxin A (OA) levels in human blood and milk samples may be due to differences in dietary habits. The purpose of this study was to examine the relationship between OA contamination of human milk and dietary intake. Human milk samples were collected from 80 Norwegian women. The usual food intake during the last year was recorded using a quantitative food frequency questionnaire. The concentration of OA in the human milk was determined by HPLC (detection limit 10 ng/l). Seventeen (21%) out of 80 human milk samples contained OA in the range 10-182 ng/l. The women with a high dietary intake of liver paste (liverwurst, liver pâté) and cakes (cookies, fruitcakes, chocolate cakes, etc.) were more likely to have OA-contaminated milk. The risk of OA contamination was also increased by the intake of juice (all kinds). In addition, the results indicate that breakfast cereals, processed meat products, and cheese could be important contributors to dietary OA intake. OA contamination of the milk was unrelated to smoking, age, parity, and anthropometric data other than body weight.

Situation of mycotoxins in milk, dairy products and human milk in Egypt

ABSTACT: Milk and dairy products purchased at Egyptian markets and breast milk from lactating mothers in Cairo and Giza governorates were analyzed for some mycotoxins. Three of 15 cows' milk samples were found positive for Afl. M1 with mean value 6.3 ppb. Only one sample of dried milk was positive (5 ppb). Two of 10 hard cheese samples contained detectable levels of Afl. M1 (3and 6 ppb), whereas one sample containing Afl. B1 and G1 (10 and 4 ppb resp.). For soft cheese one sample of 10 was positive for Afl. M1 (0.5 ppb). Blue veined cheeses were free of Afl. M1 and PR-toxins.For breast milk two of 10 samples were positive for Afl. M1 (20%) with mean value 2.75 ppb, while 3 of 10 samples were positive for Ochratoxin A (30 %).

Transfer of ochratoxin A during lactation: exposure of suckling via the milk of rabbit does fed a naturally-contaminated feed

The transfer of ochratoxin A from the blood to the milk of lactating rabbit does and subsequently the exposure of their sucklings to the mycotoxin were investigated. An effective transfer of ochratoxin A from blood to milk was shown in lactating rabbit does fed a naturally-contaminated diet (10-20 g/kg of body weight/day) throughout a lactation period of 19 days. The ochratoxin A concentrations in plasma and in milk did not significantly change throughout the lactation period with a mean milk/plasma concentration ratio of 0.015. These variables were however significantly correlated (p < 0.05), as were the ingested amounts and milk concentrations. At slaughter, the highest concentration of ochratoxin A accumulated in the body of the rabbit does were found in kidney (1.2 g/kg) followed by liver (158 ng/kg), mammary gland (105 ng/kg) and muscle (38 ng/kg). A linear relationship was found between the ochratoxin A concentrations in milk and in the plasma of the sucklings, indicating an effective transfer of the toxin to the sucklings. If the same is true in humans, the exposure of the breast-fed infant to the toxin, which has been largely reported in the literature, should be a major matter of concern for human health.

Analysis of serum and seminal plasma after feeding ochratoxin A with breeding boars

The aim of the experiment was to investigate whether or not ochratoxin A (OA) can be detected in seminal plasma after feeding the toxin in five and 10 times of the human tolerable daily intake with breeding boars and how toxin profiles of serum and seminal plasma correspond to each other. In addition to that, the effect of the toxin challenge on motility and longevity of boar semen was also evaluated. OA from samples was analyzed by microplate ELISA. Percentage of progressive motility of spermatozoa was determined initially and after 24, 48, 96, 120 and 144 h of storage. OA appeared in serum and seminal plasma shortly after toxin application had started. Significant reduction of initial motility and impaired longevity was observed after toxin withdrawal. These findings suggest that OA might have the potential to affect sperm production and semen quality of boars, but further research is required to elucidate whether OA exerts direct effect on germinal epithelium or disturbs sperm cell maturation only.

Chromatographic methods for the determination of ochratoxin A in animal and human tissues and fluids

This paper gives a review of chromatographic methods used for the determination of ochratoxin A (OA) in animal and human tissues and fluids. These methods are needed for example for monitoring studies of OA occurrence in the food chain and for studies dealing with the OA carry-over. In this survey, emphasis was given to HPLC methods. The review includes sampling, sample storage, extraction, spiking procedures, clean-up, detection and determination, and confirmation procedures. Emphasis is laid on special problems associated with the analysis of animal tissues and fluids.

A 4-year study of plasma ochratoxin A in a selected population in Tokyo by immunoassay and immunoaffinity column-linked HPLC

Employing a competitive ELISA (cELISA) based on monoclonal antibody and a novel immunoaffinity-column (IAC)-linked HPLC-fluorometry, ochratoxin A (OTA) levels in the plasma of 184 healthy volunteers (130 males, 54 females) were surveyed in Tokyo during the 4 years from 1992 to 1996. It was found that 85% of the cases were positive for OTA except 38% in 1994, and an average value in the positives was estimated as 68 pg/ml. This suggests that the population in Tokyo is exposed to OTA at high frequency, although the level in plasma is far less than that reported in Europe and Canada. A partial contribution of fermented dietary foodstuffs, coffee and wine is suspected as the source of the OTA observed in the human plasma.

Formation of DNA adducts in tissues of mouse progeny through transplacental contamination and/or lactation after administration of a single dose of ochratoxin A to the pregnant mother

Ochratoxin A (OTA) is a mycotoxin which has been detected in foods of plant origin, in edible animal tissues, and in human sera, urine, and milk in many countries. OTA is nephrotoxic and carcinogenic in mice and rats and is suspected to play a key role in the etiology of Balkan endemic nephropathy and/or associated urinary tract tumors. In the present study, some early signs of genetic impairment, including the presence of DNA adducts in target tissues from the progeny of mice after administration of a single OTA dose during late pregnancy, have been investigated. By the 32P-postlabeling method, several characteristic DNA adducts with the same Rf values were detected in kidney and liver of both the OTA-treated mice and their progeny the fetus and the offspring. No adduct was found in tissues from control animals. Different adducts were most important in kidney and liver DNA and some were organ-specific. High levels of DNA adducts were detected in the kidneys of male progeny, whereas in the female progeny and the mothers they were detected almost exclusively in the liver. This result correlates well with the carcinogenicity in mice: the target organ for males is the kidney, while for females it is the liver. High levels of DNA adducts were also found in fetuses. These results provide evidence for a direct genotoxic action of OTA in the progeny through transplacental contamination, which constitutes a new serious health hazard of exposure to this toxin.

Ochratoxin production by Aspergillus species

Ochratoxin production was tested in 172 strains representing species in sections Fumigati, Circumdati, Candidi, and Wentii of the genus Aspergillus by an immunochemical method using a monoclonal antibody preparation against ochratoxin A. Ochratoxin A was detected in Aspergillus ochraceus, A. alliaceus, A. sclerotiorum, A. sulphureus, A. albertensis, A. auricomus, and A. wentii strains. This is the first report of production of ochratoxins in the latter three species. Ochratoxin production by these species was confirmed by high-performance thin-layer chromatography and by high-performance liquid chromatography. The chemical methods also indicated the production of ochratoxin B by all of the Aspergillus strains mentioned above.

Determination of ochratoxin A in regional samples of cow's milk from Germany

Samples (121) of cow's milk from a northern region of Germany were analysed for the occurrence of ochratoxin A by means of a sensitive high-performance liquid chromatographic (HPLC) method. The samples were extracted with a mixture of chloroform and methanol at pH < 2. The extracts were cleaned up by solid-phase extraction on silica gel cartridges. The detection limit was 0.01 ng/ml, the quantitation limit was estimated at 0.03 ng/ml. The mean recovery from spiked samples was 84 +/- 7% in the concentration range of 0.03-0.5 ng/ml. An enzyme-linked immunosorbent-assay (ELISA) was shown to be suitable for the confirmation of ochratoxin A levels down to the detection limit of the HPLC method. No ochratoxin A was detected in the samples analysed, either by HPLC or by ELISA.

Immunochemical detection of ochratoxin A in black Aspergillus strains

One hundred and fifty-seven strains belonging to Aspergillus section Nigri were tested for ochratoxin A production using three different methods: a relatively new immunochemical method based on an enzyme-linked immunosorbent assay (ELISA), thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). The monoclonal antibody-based ELISA technique was successfully used to screen for low levels of ochratoxin A in the black Aspergilli without concentrating the culture filtrates. The results were confirmed by TLC and HPLC analysis and chemical derivatization. These latter methods required concentrated filtrates. Ochratoxin A was detected in the culture filtrates of five of the 12 A. carbonarius strains, none of the 45 A. japonicus strains and three of the 100 isolates in the A. niger aggregate (A. foetidus, A. awamori and A. niger.

The incidence and distribution of ochratoxin A in western Canadian swine

A survey of swine destined for slaughter in Manitoba was conducted to examine the incidence of ochratoxin A (OA) in swine herds from different regions of Manitoba throughout the year 1989-90. Thirty-six percent of the serum samples which were collected from 1600 pigs contained detectable levels of OA. The identity of this toxin was confirmed using liquid chromatography-mass spectrometry and enzymatic hydrolysis. There was a significant effect of the region from which the herds originated, as well as the season in which the samples were collected on both the incidence (p < 0.001) and concentration of OA (p < 0.001). In July, 65% of the samples contained detectable levels of OA, compared with 38, 21 and 17%, in April, October and January respectively. Furthermore, 24% of the samples collected in July contained greater than 15 ng/ml of OA, while only 2, 9, and 1% of the samples collected in April, October and January respectively, contained greater than 15 ng/ml of OA. Based on the six samples collected from each herd, it appears that the presence and concentration of OA within a herd may be estimated from a limited number of animals per herd.

Ochratoxin A and aflatoxins in breast milk samples from Sierra Leone

Breast milk from 113 mothers in two 'Under-Five Clinics' in the Southern Province of Sierra Leone, namely, Njala and Bo, were examined for their mycotoxin content. Only 10 were mycotoxin-free. Eighty-eight per cent of samples contained various aflatoxins and 35% contained ochratoxin A (OTA). Few samples (15%) had a single mycotoxin. Thirty-six (32%) had two mycotoxins and 50 (40%) had three or more. The occurrence of OTA in combination with various aflatoxins was recorded. It is concluded that infants in Sierra Leone are exposed to OTA and aflatoxins at levels which in some cases far exceed those permissible in animal feed in developed countries.

Ochratoxin A in human blood in relation to nephropathy in Tunisia

The determination of ochratoxin A (OTA) in human blood in Tunisian populations is underway. The range of contamination is between 0.7 to 7.8 ng ml-1 for the general population and 12 to 55 ng ml-1 for people suffering from chronic renal failure. It appears that 21 to 64% of people suffering from nephropathy are OTA positive with a detection limit of 1ng ml-1. This situation prompted us to search for possible association of OTA contamination and nephropathy resembling Balkan endemic nephropathy. The classification of the ill population into chronic interstitial nephropathy (CIN), chronic glomerular nephropathy (CGN), chronic vascular nephropathy (CVN) and others, indicated that the largest is the CIN group which is significantly different from the other groups, and from the control (P < 0.005). Furthermore, it presented the highest OTA mean values (25 to 59 ng ml-1) compared with the control, CGN, CVN and other groups (6 to 18 ng ml-1) according to the designated region in Tunisia. The rural population seems to be more exposed to ochratoxins in Tunisia, as has been previously reported in the Balkans and Western Europe. Altogether, these results emphasise that in Tunisia an endemic ochratoxin-related nephropathy is probably occurring.

Evaluation of ochratoxin A level in human milk in Italy

In order to estimate the incidence of ochratoxin A (OA) in biological fluids, a study was carried out to determine the concentration of OA in breast milk of donor mothers in Italy. Out of 111 samples, 22 were contaminated in the range 0.1-12 micrograms/kg.

Determination of ochratoxin A at the ppt level in human blood, serum, milk and some foodstuffs by high-performance liquid chromatography with enhanced fluorescence detection and immunoaffinity column cleanup: methodology and Swiss data

An improved specific analytical method for ochratoxin A (OA) is presented, combining HPLC separation with enhanced fluorescence detection by post-column addition of ammonia. Commercial immunoaffinity columns (Biocode) were for the first time applied to the cleanup of extracts of body fluids; they could be used up to 20 times for blood serum. The extraction efficiency of OA from human serum and milk as well as its derivatization to esters were studied and improved. The quantitation limit for OA was improved and estimated at 5-10 pg/g for human milk and serum. The mean recovery of OA from serum and milk was estimated at 85%. The overall coefficient of variation for OA determinations in serum, milk and selected foodstuffs was estimated at 10% (concentration range 0.01-5 ng/g). The method was applied to sera of 368 blood donors, 10 pairs of maternal and fetal sera, as well as to 40 human milk samples and selected foodstuffs; the results are discussed.

Ochratoxin A levels in human milk and related food samples: an exposure assessment

Ochratoxin A (OA) is a mycotoxin detected in a variety of food and feeds mostly from countries with temperate or continental climate, because the fungi that produce it, mainly Aspergillus ochraceus, Penicillium verrucosum, and Penicillium viridicatum, can grow under a great variety of climate conditions. The aim of this article was, firstly, to confirm the occurrence of OA in human milk in Italy. Then, a preliminary calculation of OA intake via human milk was made, from ingested food. For this investigation, food and milk samples were collected, continuously for a week, from 4 lactating mothers. The obtained results revealed a significant exposure of sucklings and mothers to OA levels higher than the tolerable daily intake as estimated from animal models. On the basis of these data, a major effort in planning surveillance and research programs to control OA contamination in food, feed, and biological fluids should be pursued.

Human fetal exposure to ochratoxin A and aflatoxins

Analysis of 64 cord blood samples from pregnant women in Sierra Leone revealed the presence of ochratoxin A (OTA) and aflatoxins in 25% and 58% of samples, respectively. Of the eight maternal blood samples collected during delivery, one contained OTA and aflatoxins were detected in six. There was no relationship between mycotoxins in maternal and cord blood. The effect these toxins might have had on the birthweight of infants is discussed.

Transfer of ochratoxin A from lactating rats to their offspring: a short-term study

A dose-dependent transfer of ochratoxin A into the milk of lactating rats was found after a single oral dose of ochratoxin A, given in the dose levels of 10, 50, and 250-micrograms ochratoxin A/kg body weight by gastric intubation. The milk/blood concentration ratio of ochratoxin A at 24 and 72 h was 0.4 and 0.7, respectively. A linear relationship was found between the concentration of ochratoxin A in the dam's milk and in the blood of the pups at 72 h, as well as in the dam's milk and in the kidneys of the pups. The pup blood/milk concentration ratio of ochratoxin A was approximately 6. At 72 h the sucklings had higher levels of ochratoxin A than their dams in both blood and kidneys. The results show that the concentration of ochratoxin A in milk can be used as an indicator of the continuously administered dose to the suckling.