Occurrence of aflatoxins B1, B2, G1 and G2 in cooked food components of whole meals marketed in fast food outlets of the city of Sa~o Paulo, SP, Brazil

Samples of cooked components of regular meals served at fast food outlets of the city of Sa~oPaulo, Brazil were analysed for aflatoxins B₁, B₂, G₁ and G₂. The 322 samples were composed of prepared traditional Brazilian and ethnic foods in which aflatoxins might be present. Thin-layer chromatography was used for separation of the compounds and their determination was achieved by both long wave UV light and fluorodensitometry. Aflatoxins were detected in 30 samples (9.31% of the total) in a range of 2.80 to 1323 ng/g for B_{1 +} B_{2 +} G_{1 +} G₂ with 90th percentiles of 158 (B_{1 +} G₁) and 258 (B_{1 +} B_{2 +} G_{1 +} G₂). Aflatoxin B₁ was detected in all contaminated samples. The contamination levels and frequency of aflatoxins B₁ and G₁ in positive samples above 20 ng/g in this study are high, indicating that there is a certain degree of exposure of the population to the carcinogenic aflatoxin.     

Survey of aflatoxins in beer sold in Canada

Between March 1998 and March 2002, 304 samples of domestic (Canadian) and imported beers from 36 countries were picked up for the determination of aflatoxins B₁, B₂, G₁ and G₂. Twelve samples were positive with aflatoxins greater than the limit of quantitation (LOQ) (aflatoxin B₁, 4.4 ng l^-1; aflatoxin B₂, 3.4 ng l^-1; aflatoxin G₁, 11.2 ng l^-1; and aflatoxin G₂, 6.2 ng l^-1). Five samples from Mexico, two samples from Spain and one from Portugal contained aflatoxin B₁. Four samples from India contained aflatoxins B₁ and B₂. The remaining samples contained less than the LOQ for aflatoxins B₁, B₂, G₁ and G₂. The analytical method for this survey was based on that of Scott and Lawrence (Scott PM, Lawrence GA. 1997. Determination of aflatoxins in beer. Journal of AOAC International 80:1229-1234.). Aflatoxins B₁, B₂, G₁ and G₂ were determined at parts per trillion (ng l^-1) levels in beer by immunoaffinity column cleanup followed by derivatization with trifluoroacetic acid and reversed-phase liquid chromatography with fluorescence detection.     

Natural co-occurrence of fumonisins, deoxynivalenol, zearalenone and aflatoxins in field trial corn in Argentina

Corn samples collected from the main production area in Argentina in 1995 were surveyed for the natural occurrence of Fusarium mycotoxins and aflatoxins. Fumonisins B₁, B₂ and B₃ and zearalenone were found in all samples. A positive relationship was found between fumonisins B₁, B₂ and B₃, B₁ and B₃, and B₂ and B . Deoxynivalenol and aflatoxins were not de3 tected. Mycological survey has also revealed the predominance of Fusarium moniliforme . This is the first report on the simultaneous occurrence of fumonisins and zearalenone in corn from the main production area in Argentina.     

Aflatoxins in ginseng roots

Ginseng roots can be infected by molds during growth, harvest and storage and result in contamination with mycotoxins. In this study, an analytical method for the determination of aflatoxins B₁, B₂, G₁ and G₂, a group of structurally similar mycotoxins, in ginseng root was developed. Test samples were extracted with methanol-water (8 + 2), diluted and passed through an immunoaffinity column packed with antibodies specific for aflatoxins. The purified extract was then derivatized with a mixture of water, trifluoroacetic acid and acetic acid. Aflatoxins were then separated and quantified by reverse phase liquid chromatography (LC) with fluorescence detection. Recoveries of total aflatoxins at 2, 4, 8 and 16 ng/g added to toxin-free 4 to 5-year old dried sliced Wisconsin ginseng were 92, 77, 91 and 83% respectively; and relative standard deviations were 3.6, 8.0, 6.9 and 2.0% respectively. A total of 11 wild simulated and 12 cultivated ginseng root samples were analysed for aflatoxins. All cultivated roots were found to be free of aflatoxin contamination. Two of the wild simulated roots contained total aflatoxins B₁, B₂, G₁ and G₂ at 15.1 and 15.2 ng/g. One moldy ginseng root purchased from a grocery store was found to be contaminated with aflatoxins at 16 ng/g.     

Aflatoxins in spices marketed in Portugal

Seventy-nine prepackaged samples of 12 different types of spice powders (five cardamom, five cayenne pepper, eight chilli, five cloves, seven cumin, five curry powder, five ginger, five mustard, 10 nutmeg, 12 paprika, five saffron and seven white pepper) were selected from supermarkets and ethnic shops in Lisbon (Portugal) for estimation of aflatoxins by immmunoaffinity column clean-up followed by HPLC. Aflatoxin B (AFB) was detected in 34 samples of prepackaged spices (43.0%). All of the cayenne pepper samples were contaminated with levels ranging from 2 to 32 µ g AFB / kg. Three nutmeg samples contained levels ranging from 1 to 5 µ g/kg, three samples had levels ranging from 6 to 20 µ g/kg, and there were two with 54 µ g/kg and 58 µ g/ kg. Paprika contained levels of aflatoxin B₁ ranging from 1 to 20 µ g/kg. Chilli, cumin, curry powder, saffron and white pepper samples had levels ranging from 1 to 5 µ g/kg. Aflatoxins were not detected in cardamom, cloves, ginger and mustard. None of the samples analysed contained aflatoxins B₂, G₁ and G₂.     

市售调味酱中5种真菌毒素的测定

建立了用超高效液相色谱-串联质谱同时检测芝麻酱、花生酱及黄豆酱中5种真菌毒素(黄曲霉毒素B1、黄曲霉毒素B2、黄曲霉毒素G1、黄曲霉毒素G2、赭曲霉毒素A)的检测方法.样品采取乙腈-甲酸-水(70∶1∶29,体积比)混合溶液提取,利用多功能净化柱净化,采用1％的甲酸水相和混合甲醇-乙腈有机相进行梯度洗脱,经多反应监测模...     

Occurrence of aflatoxins in layer feed and corn samples in Konya province, Turkey

The natural occurrence ofaflatoxin was investigated in layer feed and corn samples brought to Konya Veterinary Control and Research Institute Laboratory between 15 April and 15 December 2002. Seventy-eight samples (52 feeds, 26 corn samples) were analysed for total aflatoxin (B₁ + B₂ + G₁ + G₂) by an ELISA screening method. Aflatoxin contamination was determined in 37 feed samples (71.1%) and 15 corn samples (57.7%), with a range of1.5-133 μg kg^-1. However, a majority ofthe aflatoxin contamination was less than 5 μg kg^-1 (50% within the positive samples). Two feed samples and two corn samples exceeded the maximum tolerated levels in feed (20 μg kg^-1) and feedstuffs (50 μg kg^-1) for total flatoxin.     

Consumers' ability to discriminate aflatoxin-contaminated Brazil nuts

The objectives of the study were to investigate the extent to which consumers can separate nuts with a high content of aflatoxin from sound nuts, and whether sorting results can be improved by information or whether they are affected by certain factors. A test panel consisting of 100 subjects was asked to crack 300 g Brazil nuts and to sort the nuts into those they considered edible and inedible. The test showed that consumers can, on current behaviour, discriminate aflatoxin-contaminated Brazil nuts to a significant extent. The median and the 95th percentile of the total concentrations of aflatoxins (B₁, B₂, G₁, G₂) in the samples before sorting were 1.4 and 557 µg kg^-1, respectively, and in the edible fractions after sorting 0.4 and 56 µg kg^-1, respectively. Given that levels of aflatoxins before sorting exceed either 2 µg aflatoxin B₁ kg^-1 or totally 4 µg aflatoxins kg^-1, there was no effect of aflatoxin concentrations before sorting on the probability of exceeding these thresholds in the edible fraction. This means that similar sorting results were obtained for samples with aflatoxin levels exceeding either of the two thresholds, irrespective of if the thresholds were exceeded with a few µg kg^-1 or up to more than 1000 µg kg^-1. None of the tested factors (such as sex, age, level of education, ethnic background or knowledge of mycotoxins) had any effects on the probability of exceeding either of the two aflatoxin thresholds.     

Mycotoxins in infant cereal foods from the Canadian retail market

Three hundred and sixty-three samples of cereal-based infant foods were collected from the Canadian retail marketplace over 3 years. The samples included oat-, barley-, soy-, and rice-based infant cereals, mixed-grain infant cereals, teething biscuits, creamed corn, and soy-based formulas. Samples were analysed for targeted mycotoxins (deoxynivalenol, nivalenol, HT-2 toxin, zearalenone, ochratoxin A, fumonisins B₁ and B₂, and five ergot alkaloids). Soy-based cereals (which usually contain corn) exhibited the highest incidences of deoxynivalenol (100%), zearalenone (46%) and fumonisins (75%). Overall, deoxynivalenol was the most frequently detected mycotoxin -- it was detected in 63% of samples analysed. Survey results demonstrated the regular occurrence of multiple mycotoxins in cereal-based infant foods.     

Aflatoxin formation and gene expression in response to carbon source media shift in Aspergillus parasiticus

Aflatoxins are toxic and carcinogenic polyketide metabolites produced by fungal species, including Aspergillus flavus and A. parasiticus. The biosynthesis of aflatoxins is modulated by many environmental factors, including the availability of a carbon source. The gene expression profile of A. parasiticus was evaluated during a shift from a medium with low concentration of simple sugars, yeast extract (YE), to a similar medium with sucrose, yeast extract sucrose (YES). Gene expression and aflatoxins (B₁, B₂, G₁, and G₂) were quantified from fungal mycelia harvested pre- and post-shifting. When compared with YE media, YES caused temporary reduction of the aflatoxin levels detected at 3-h post-shifting and they remained low well past 12 h post-shift. Aflatoxin levels did not exceed the levels in YE until 24 h post-shift, at which time point a tenfold increase was observed over YE. Microarray analysis comparing the RNA samples from the 48-h YE culture to the YES samples identified a total of 2120 genes that were expressed across all experiments, including most of the aflatoxin biosynthesis genes. One-way analysis of variance (ANOVA) identified 56 genes that were expressed with significant variation across all time points. Three genes responsible for converting norsolorinic acid to averantin were identified among these significantly expressed genes. The potential involvement of these genes in the regulation of aflatoxin biosynthesis is discussed.     

REDUCTION OF FUNGI AND MYCOTOXINS FORMATION IN SEEDS BY GAMMA-RADIATION

Ninety samples of maize, chick-peas and groundnut seeds collected from the Egyptian market were found to be heavily contaminated by molds. Alternaria, Aspergillus, Cladosporium, Eurotium, Fusarium, Mucor, Penicillium and Rhizopus were the most common fungal genera isolated from nondisinfected seeds . Aspergillus alutaceus, A. flavus, Fusarium verticillioides and F. oxysporum were isolated from all surface-disinfected seeds and were reported to produce ochratoxin A, aflatoxin B₁ and zearalenone, respectively. Irradiation at a dose 4.0 kGy reduced the mold growth greatly relative to unirradiated controls. There was no growth at dose 5.0 kGy. On the basis of the radiation survival data, the decimal reduction values D₁₀ for A. alutaceus, A. flavus and F. verticilliodies were 0.70. 2.10 and 0.93 kGy in maize. A dose of 5 kGy inhibited the toxigenic molds and mycotoxin formation in seeds. Aflatoxin B₁ and ochratoxin A were detected in maize and chick-peas, whereas zearalenone was detected in maize samples. Application of radiation at a dose of 6.0 kGy detoxified aflatoxin B₁ by 74.3–76.7%, ochratoxin A by 51.3–96.2% and zearalenone by about 78%.     

Mycotoxins in breakfast cereals from the Canadian retail market: A 3-year survey

One hundred and fifty-six samples of breakfast cereals were collected from the Canadian retail marketplace over a 3-year period. The samples were analysed for the mycotoxins deoxynivalenol, nivalenol, HT-2 toxin, zearalenone, ochratoxin A, and fumonisins B₁ and B₂ to contribute to dietary exposure estimates in support of the development of Canadian guidelines for selected mycotoxins in foods. The samples included corn-, oat-, wheat- and rice-based cereals, as well as mixed-grain cereals, and were primarily from North American processors. Overall, deoxynivalenol was the most frequently detected mycotoxin  — it was detected in over 40% of all samples analysed. Fumonisins and ochratoxin A were each detected in over 30% of all samples. Zearalenone was detected in over 20% of all samples. Nivalenol and HT-2 toxin were each detected in only one sample. The survey clearly demonstrated regular occurrence of low levels of multiple mycotoxins in breakfast cereals on the Canadian market.     

Aflatoxins in stored maize and rice grains in Liaoning Province, China

Aflatoxin contamination and its relationship to storage length in stored maize and rice in Liaoning Province, northeastern China, was investigated. Aflatoxins in 110 samples collected from an area of 14.68 million km² covering storage length from 1 yr to over 10 yr were determined by high-performance liquid chromatography with fluorescence detection. The results showed that almost all samples collected contained aflatoxins. The average contents in maize, whole grain rice and brown rice were found to be 0.99, 3.87 and 0.88 μg kg⁻¹, respectively. Three-fourths of the total aflatoxins in whole grain rice (3.87 μg kg⁻¹) could be removed by dehusking to as low as 0.88 μg kg⁻¹ in brown rice. No significant aflatoxin increase was observed in whole grain rice and brown rice over a 10-yr storage period. In maize, the amount of aflatoxins was significantly higher in 2-yr than 1-yr sample. Aflatoxin G₁ was detected as the major type of aflatoxin in over 40% of all stored grain samples tested and over 92% of rice samples examined. The aflatoxin content in maize and rice is much lower than the regulated maximum amount allowed in foodstuffs in China and other countries. We concluded that these grains are safe for human and livestock consumption and for trading.     

LC-MS/MS multi-method for mycotoxins after single extraction, with validation data for peanut, pistachio, wheat, maize, cornflakes, raisins and figs

Mycotoxin analysis is usually carried out by high performance liquid chromatography after immunoaffinity column cleanup or in enzyme-linked immunosorbent assay tests. These methods normally involve determination of single compounds only. EU legislation already exists for the aflatoxins, ochratoxin A and patulin in food, and legislation will come into force for deoxynivalenol, zearalenone and the fumonisins in 2007. To enforce the various legal limits, it would be preferable to determine all mycotoxins by routine analysis in different types of matrices in one single extract. This would also be advantageous for HACCP control purposes. For this reason, a multi-method was developed with which 33 mycotoxins in various products could be analysed simultaneously. The mycotoxins were extracted with an acetonitrile/water mixture, diluted with water and then directly injected into a LC-MS/MS system. The mycotoxins were separated by reversed-phase HPLC and detected using an electrospray ionisation interface (ESI) and tandem MS, using MRM in the positive ion mode, to increase specificity for quality control. The following mycotoxins could be analysed in a single 30-min run: Aflatoxins B1, B2, G1 and G2, ochratoxin A, deoxynivalenol, zearalenone, T-2 toxin, HT-2 toxin, alpha-zearalenol, alpha-zearalanol, beta-zearalanol, sterigmatocystin, cyclopiazonic acid, penicillic acid, fumonisins B1, B2 and B3, diacetoxyscirpenol, 3- and 15-acetyl-deoxynivalenol, zearalanone, ergotamin, ergocornin, ergocristin, alpha-ergocryptin, citrinin, roquefortin C, fusarenone X, nivalenol, mycophenolic acid, alternariol and alternariol monomethyl ether. The limit of quantification for the aflatoxins and ochratoxin A was 1.0 microg kg(-1) and for deoxynivalenol 50 microg kg(-1). The quantification limits for the other mycotoxins were in the range 10-200 microg kg(-1). The matrix effect and validation data are presented for between 13 and 24 mycotoxins in peanuts, pistachios, wheat, maize, cornflakes, raisins and figs. The method has been compared with the official EU method for the determination of aflatoxins in food and relevant FAPAS rounds. The multi-mycotoxin method has been proven by the detection of more than one mycotoxin in maize, buckwheat, figs and nuts. The LC-MS/MS technique has also been applied to baby food, which is subject to lower limits for aflatoxin B1 and ochratoxin A, ergot alkaloids in naturally contaminated rye and freeze-dried silage samples.     

玉米赤霉烯酮间接竞争ELISA方法的建立

本研究以玉米面为例,建立了玉米赤霉烯酮间接竞争ELISA (ic-ELISA)方法.采用棋盘滴定法确定抗原和单抗的最佳工作浓度,并确定了抗原37℃包被1h、不封闭、酶催化底物作用时间15 min的反应条件进行检测.该方法的检测范围(IC20～IC80)为11 ～292 pg/mL,检测限(IC10)为6 pg/mL.玉...     

LC-MS/MS multi-method for mycotoxins after single extraction, with validation data for peanut, pistachio, wheat, maize, cornflakes, raisins and figs.

Mycotoxin analysis is usually carried out by high performance liquid chromatography after immunoaffinity column cleanup or in enzyme-linked immunosorbent assay tests. These methods normally involve determination of single compounds only. EU legislation already exists for the aflatoxins, ochratoxin A and patulin in food, and legislation will come into force for deoxynivalenol, zearalenone and the fumonisins in 2007. To enforce the various legal limits, it would be preferable to determine all mycotoxins by routine analysis in different types of matrices in one single extract. This would also be advantageous for HACCP control purposes. For this reason, a multi-method was developed with which 33 mycotoxins in various products could be analysed simultaneously. The mycotoxins were extracted with an acetonitrile/water mixture, diluted with water and then directly injected into a LC-MS/MS system. The mycotoxins were separated by reversed-phase HPLC and detected using an electrospray ionisation interface (ESI) and tandem MS, using MRM in the positive ion mode, to increase specificity for quality control. The following mycotoxins could be analysed in a single 30-min run: Aflatoxins B1, B2, G1 and G2, ochratoxin A, deoxynivalenol, zearalenone, T-2 toxin, HT-2 toxin, alpha-zearalenol, alpha-zearalanol, beta-zearalanol, sterigmatocystin, cyclopiazonic acid, penicillic acid, fumonisins B1, B2 and B3, diacetoxyscirpenol, 3- and 15-acetyl-deoxynivalenol, zearalanone, ergotamin, ergocornin, ergocristin, alpha-ergocryptin, citrinin, roquefortin C, fusarenone X, nivalenol, mycophenolic acid, alternariol and alternariol monomethyl ether. The limit of quantification for the aflatoxins and ochratoxin A was 1.0 microg kg(-1) and for deoxynivalenol 50 microg kg(-1). The quantification limits for the other mycotoxins were in the range 10-200 microg kg(-1). The matrix effect and validation data are presented for between 13 and 24 mycotoxins in peanuts, pistachios, wheat, maize, cornflakes, raisins and figs. The method has been compared with the official EU method for the determination of aflatoxins in food and relevant FAPAS rounds. The multi-mycotoxin method has been proven by the detection of more than one mycotoxin in maize, buckwheat, figs and nuts. The LC-MS/MS technique has also been applied to baby food, which is subject to lower limits for aflatoxin B1 and ochratoxin A, ergot alkaloids in naturally contaminated rye and freeze-dried silage samples.     

Spectral analyses of fluorescences in dent maize infected with Aspergillus flavus and Aspergillus parasiticus

Bright greenish yellow (BGYF) and blue white (BWF) fluorescences were associated with Aspergillus flavus and A. parasiticus infected maize. The fluorescences were studied spectrofluorometrically, the BGYF exhibiting a peak wave length between 480–485 nm and the BWF between 440–445 nm. Neither fluorescence varied in maize stored under different moistures and temperatures.

BWF was similar spectrally to the fluorescence of the endosperm of sound kernels but × 5 20 more intense. The spectrum of BWF was similar to Aflatoxin G₁ or a mixture of aflatoxin B₁, B₂, G₁ and G₂ when they were spotted on endosperm tissue. A color reference for BGYF was similar in peak wave length to BGYF. Amsoy soybeans without the seed coat fluoresced with a peak 470–475 nm and the intensity was low compared to BGYF in maize. A fluorescence of maize kernels visually similar to BGYF but not associated with Aspergillus infection or aflatoxin contamination was also investigated. This “false BGY” fluorescence was spectrally similar to the BGYF in infected kernels.     

Aflatoxin and ochratoxin A content of spices in Hungary

In October and November 2004, 91 spice samples (70 ground red pepper, six black pepper, five white pepper, five spice mix and five chilli samples), the majority of which originated from commercial outlets, were analysed for aflatoxins B₁, B₂, G₁ and G₂ (AFB1, AFB2, AFG1, AFG2) and ochratoxin A (OTA) content by high-performance liquid chromatography (HPLC) after immunoaffinity column clean-up. Eighteen of the 70 ground red pepper samples contained AFB1, seven of them in a concentration exceeding the 'maximum level' of 5 µg kg^-1 (range 6.1-15.7 µg kg^-1). Of the other spices assayed, the AFB1 contamination of one chilli sample exceeded 5 µg kg^-1 (8.1 µg kg^-1). Thirty-two of the 70 ground red pepper samples contained OTA, eight of them in a concentration exceeding the 10 µg kg^-1 'maximum level' (range 10.6-66.2 µg kg^-1). One chilli sample was contaminated with OTA at 2.1 µg kg^-1. The AFB1 and OTA contamination of ground red pepper exceeding the 'maximum level' (5 and 10 µg kg^-1, respectively) was obviously the consequence of mixing imported ground red pepper batches heavily contaminated with AFB1 and OTA with red pepper produced in Hungary. This case calls attention to the importance of consistently screening imported batches of ground red pepper for aflatoxin and ochratoxin A content and strictly prohibiting the use of batches containing mycotoxin concentrations exceeding the maximum permitted level.     

Fumonisin B1, fumonisin B2, zearalenone and ochratoxin A contamination of maize in Croatia

Mycotoxins are products of moulds that frequently contaminate maize. In this study the presence of mycotoxins fumonisin B₁ (FB₁), fumonisin B₂ (FB₂), zearalenone (ZEA) and ochratoxin A (OTA) was determined in 49 maize grain samples collected in autumn 2002. The most frequent finding was that of FB₁(100%), followed by ZEA (84%) and OTA (39%), while FB₂ was found only in three samples. The co-occurrence of two and three mycotoxins was found in 55 and 37% of samples, respectively. The concentrations (mean ± SD) of FB₁, ZEA and OTA in positive samples were 459.8 ± 310.7, 3.84 ± 6.68 and 1.47 ± 0.38 µg kg^-1, respectively, and the concentrations of FB₂ in three positive samples were 68.4, 109.2 and 3084.0 µg kg^-1. Although such low concentrations of mycotoxins are not a significant source of exposure in countries with a European diet, a few samples with extreme values indicate that thorough control is needed.