No abstract

Alternariol (AOH), alternariol monomethyl ether (AME) and tenuazonic acid (TEA) are secondary metabolites of Alternaria species. Cyclopiazonic acid (CPA) is produced by fungi belonging to the ubiquitous genera of Penicillium and Aspergillus and has been found in a wide range of foods. These toxins were searched for by liquid chromatography with diode-array detection in tomato products processed and sold in Brazil. Eighty samples of tomato products were examined (juice 11, pulp 22, purée 22, paste 24 and whole stewed tomato 1). Eleven brands sold nationwide were covered. TEA was found in seven samples of tomato pulp (39-111 ng/g) and four samples of tomato puree (29-76 ng/g). CPA was found in six samples of pulp (64-178 ng/g) and two samples of purée (36-117 ng/g). Co-occurrence of TEA and CPA was found in two samples of purée and one of pulp. This is the first time that the presence of CPA has been reported in tomato products. Neither AME nor AOH were detected in the samples.

Thirty-four samples of roast and ground coffee, 14 samples of instant coffee and two samples of decaffeinated instant coffee were collected in markets and supermarkets in the city of Campinas, Brazil, and analysed for ochratoxin A using immunoaffinity columns for clean-up and HPLC with fluorescence detection for quantification. The limit of detection was 0.2 ng/g ochratoxin A. Twenty-three samples of ground and roast coffee were found to be contaminated with the toxin at levels ranging between 0.3 and 6.5 ng/g. The average concentration in all 34 samples was 0.9 ng/g. All samples of instant coffee contained ochratoxin A at levels ranging from 0.5 to 5.1 ng/g, with an average figure of 2.2 ng/g. Roast and ground coffee is the type of coffee most used by Brazilians for the preparation of the beverage. Considering that an average Brazilian adult takes five cups of coffee per day, which corresponds to 30 g of roast and ground coffee, the probable daily intake of ochratoxin A by a 70 kg adult would be 0.4 ng/kg bw, which is far below the current Provisional Tolerable Daily Intake of 14 ng/kg bw for ochratoxin A as set by the Codex Alimentarius. To study the transfer of ochratoxin A into coffee brew, the beverage was prepared by two methods: (a) the drip method and (b) the Brazilian country style method. No significant difference was observed between the two methods in terms of extraction of the toxin using five contaminated samples containing between 0.8 and 6.5 ng/g ochratoxin A. The drip method extracted 86 +/- 15% and the Brazilian country style 74 +/- 20% of the ochratoxin A initially present in the roast and ground coffee.

A previously published method for ochratoxin A was evaluated and proved appropriate for simultaneous determination of aflatoxins, ochratoxin A, sterigmatocystin, and zearalenone, with considerable savings in time and reagent costs. The detection limits were 2, 5,15, and 55 μg/kg, respectively. The recoveries and coefficients of variation obtained with artificially contaminated samples were 91-101% and 0-16% for aflatoxin B1, 98-117% and 0-17% for sterigmatocystin, and 96-107% and 0-17% for zearalenone, respectively. The coefficients of variation for naturally contaminated samples (aflatoxins in rice and ochratoxin A in beans) ranged from 0 to 8%. The method was used to survey 296 samples that included 10 cultivars of dried beans, 8 types of corn products, 3 types of cassava flour, and both polished and parboiled rice between May 1985 and June 1986 in Campinas, Brazil. Only aflatoxin B, (9 samples, 20-52 μg/kg), aflatoxin G, (4 samples, 18-31 μg/kg), and ochratoxin A (5 samples, 32-160 μg/kg) were found. The average contamination percentage was 4.7%; beans showed the highest (6.6%) and rice showed the lowest (3.3%) incidence rates. Zearalenone and sterigmatocystin were not detected. Positive samples were confirmed by chemical derivatization, corroborated by development in 3 solvent systems.

resumo Levantamentos de ocorrência de micotoxinas em alimentos foram realizados nas últimas duas décadas nas regiões Sudeste e Sul do Brasil. Levantamentos em alimentos comercializados em outras regiões têm-se limitado a aflatoxinas em amendoim e castanhas do Brasil. O presente trabalho pesquisou a presença de fumonisina B 1 , aflatoxinas B 1 , B 2 , G 1 e G 2 , ocratoxina A e zearalenona em 74 amostras de produtos a base de milho adquiridas no comércio da cidade de Recife, PE, durante o período de 1999 a 2001. Fumonisina B 1 foi determinada por cromatografia líquida de alta eficiência com detecção por fluorescência e as demais toxinas foram determinadas por cromatografia em camada delgada. Fumonisina B 1 foi encontrada em 94,6% das amostras em concentrações variando de 20 a 8600 μg/kg. Apenas 5 amostras continham aflatoxina B 1 e o teor máximo encontrado foi 20 μg/kg. Duas amostras ultrapassaram o limite de 20 μg/kg para a somatória das aflatoxinas B 1 , B 2 , G 1 e G 2 (farinha de milho pré-cozida com 21,5 μg/kg e quirera (xerém) com 23,3 μg/kg). As aflatoxinas G 1 e G 2 , ocratoxina A e zearalenona não foram detectadas em nenhuma das amostras. Todas as amostras contaminadas com aflatoxinas também apresentaram fumonisina B 1 . palavras-chave: micotoxinas, fumonisina, aflatoxinas, ocratoxina A, zearalenona, produtos de milho. Research concerning the presence of mycotoxin in food has been conducted in the Southwest and South regions of Brazil over the last two decades. Research in other regions has been limited to aflatoxin in peanuts and Brazil nuts. The aim of this work is to study the presence of fumonisin B 1 , aflatoxins B 1 , B 2 , G 1 , and G 2 , ochratoxin A and zearalenone in 74 samples of corn products acquired in shops and food markets in the city of Recife (PE) from 1999 to 2001. Fumonisin B 1 was determined by high performance liquid chromatography and fluorescence was detected. The other toxins were determined by thin layer chromatography. Fumonisin B 1 was found in 94.6% of the samples in levels from 20 to 8600 μg/kg. Only 5 samples contained aflatoxin B 1 and the highest level found was 20 μg/kg. Two samples were over 20 μg/kg for the sum of B 1 , B 2 , G 1 e G 2 (21.5 μg/kg for pre-cooked corn flour and 23.3 μg/kg for corn grits). Aflatoxins G 1 and G 2 , ochatoxin A and zearalenone were not detected in any of the samples. All samples contaminated with aflatoxins were also contaminated with fumonisin B 1 .

The mycoflora of 3 hybrids of freshly harvested corn grains collected from three regions of the state of São Paulo, Brazil (Assis, Capão Bonito and Ribeirão Preto) was investigated. A total of 66 samples were analyzed focusing on the influence of abiotic factors (moisture content, water activity, temperature and rainfall) on both the prevalence of Aspergillus flavus and Fusarium moniliforme, and the ability of these genera isolates to produce aflatoxins and fumonisins, respectively. In the three surveyed regions, the fungal population comprised mainly Fusarium spp., Penicillium spp., Aspergillus spp. and 2 others filamentous fungal genera, which were isolated from corn kernels showing water activity of 0.30 to 0.99 and moisture content of 5.0% to 20.2%. Among the genera Fusarium and Aspergillus, the most frequent species were F. moniliforme and A. flavus, respectively. Concerning the toxigenic potential of F. moniliforme, all isolated strains (40) produced fumonisins at 20 µg/g to 2168 µg/g (FB 1 ) and/or 10 µg/g to 380 µg/g (FB 2 ). From the 10 A. flavus isolates, 6 strains (60.0%) produced aflatoxins at 615 µg/kg to 30.750 µg/kg (AFB 1 ) and/or 11 µg/kg to 22 µg/kg (AFB 2 ).

Wheat from two cultivars with contrasting characteristics were harvested in ten experimental plots located in wheat producing areas of the State of São Paulo, Brazil. The samples (10 of each cultivar) were analyzed by a gas-chromatographic method for deoxynivalenol (DON), nivalenol (NIV), diacetoxyscirpenol (DAS), toxins T-2 (T-2) and HT-2, T-2 tetraol, T-2 triol, and by a thin-layer chromatographic method for zearalenone (ZEN), aflatoxins B1, B2, G1, G2, ochratoxin A and sterigmatocystin. No mycotoxins were detected in 13 samples. DON was found in four samples (0.47-0.59 microgram/g), NIV in three samples (0.16-0.40 microgram/g), T-2 in two samples (0.40, 0.80 microgram/g), DAS in one sample (0.60 microgram/g), and ZEN in three samples (0.04-0.21 microgram/g). The wheat samples were also examined for the incidence of fungi. Alternaria, Drechslera, Epicoccum and Cladosporium were the prevailing genera. Among the Fusarium spp., F. semitectum was present in 19 samples and F. moniliforme in 18 samples. No F. graminearum was isolated in the samples.

Past surveys indicated that the occurrence of a¯atoxins, zearalenone and ochratoxin A was not a problem in corn and corn products in the state of Sa Ä o Paulo, Brazil. However, according to recent studies, a change in pattern has been detected. To obtain a better overview, these toxins were searched for in 110 samples of freshly harvested corn, corresponding to 48 commercial cultivars planted at three different locations in the state. A¯atoxin contamination was found in 60 (54.5%) of the samples, in levels ranging from 6 to 1600 mg kg À1 a¯atoxin B 1 . Insect control was exercised, so this was not the main route of corn infection. Endosperm type, germplasm type, number of days to¯owering, and length of time the mature corn remained in the ®eld had no effect on a¯atoxin contamination. Ochratoxin A was found in two samples (206 and 128 mgkg À1) and zearalenone in one sample (4640 mg kg À1