Adriana P. de Almeida

Genetic diversity of environmental Aspergillus flavus strains in the state of São Paulo, Brazil by random amplified polymorphic DNA

Aspergillus flavus is a very important toxigenic fungus that produces aflatoxins, a group of extremely toxic substances to man and animals. Toxigenic fungi can grow in feed crops, such as maize, peanuts, and soybeans, being thus of high concern for public health. There are toxigenic and non-toxigenic A. flavus variants, but the necessary conditions for expressing the toxigenic potential are not fully understood. Therefore, we have studied total-DNA polymorphism from toxigenic and non toxigenic A. flavus strains isolated from maize crops and soil at two geographic locations, 300 km apart, in the Southeast region of Brazil. Total DNA from each A. flavus isolate was extracted and subjected to polymerase chain reaction amplification with five randomic primers through the RAPD (random amplified polymorphic DNA) technique. Phenetic and cladistic analyses of the data, based on bootstrap analyses, led us to conclude that RAPD was not suitable to discriminate toxigenic from non toxigenic strains. But the present results support the use of RAPD for strain characterization, especially for preliminary evaluation over extensive collections.

Ochratoxin A in brazilian instant coffee

The aim of this study was to determine the ochratoxin A (OTA) contamination of instant coffee samples collected in the market of the city of Sao Paulo, Brazil from August to December, 2004. The EN 14133/2003 method, originally developed to quantify OTA in wine, grape juice and beer samples, was evaluated and approved for analyzing OTA in instant coffee samples. OTA was isolated in an immunoaffinity column and quantified by HPLC with fluorescence detection. The established detection and quantification limits were 0.16 and 0.52 ng/g, respectively. The recoveries from spiked samples were 92.6 ± 1.7, 83.7 ± 0.8, and 91.0 ± 1.2 % at levels of 3.0, 5.0, and 8.0 ng/g, respectively. Of a total of 82 samples analised, 81 (98.8%) contained OTA at levels ranging from 0.17 to 6.29 ng/g. The high frequency of OTA occurrence in the instant coffee samples demonstrates the importance of an effective control of this product by governmental authorities and industries. The rapid methodology for OTA analysis in instant coffee used in this study was defined and validated, permitting it´s use for quality control of this product.

Ochratoxin A in wines and grape juices commercialized in the city of São Paulo, Brazil

During the summer of 2005, a total of 101 samples of wines and grape juices purchased from supermarkets and retail stores in Sao Paulo city were analysed for the presence of Ochratoxin A (OTA). OTA was evaluated in 29 red wines and 38 grape juices produced in Brazil and in 34 imported red wines (from Argentina, Chile, Uruguay, France, Italy, Portugal, Spain and South Africa). OTA was extracted in an immunoaffinity column and detected by HPLC with fluorescence detection, according to EN 14133/2003. The detection and quantification limits established were 0.01 and 0.03 ng/mL, respectively. The recoveries for wine samples were 94.1, 82.5, 86.1% and the relative standard deviation were 6.10, 1.03, 4.11% at levels of 0.03, 2.0, 5.0 ng/mL, respectively. For grape juice, the recovery was 86.2% and the RSD was 2.01% at a level of 0.4 ng/mL. OTA contamination was found in nine of the 29 Brazilian red wines with levels ranging from 0.10 to 1.33 ng/mL and in 18 of the 34 imported red wines with levels ranging from 0.03 to 0.32 ng/mL. OTA was not detected in any of the grape juice samples analysed. Although the results from the wine samples analysed for the presence of OTA were below to the limits established by EC 123/2005 (2.0 ng/mL), low and continuous exposure to this mycotoxin could be a risk to human health.

Sulfonamidas em leite por cromatografia líquida de alta eficiência com derivação pré-coluna e detecção por fluorescência

O objetivo deste trabalho foi avaliar e validar um metodo para deteminacao de residuos de sulfatiazol (STZ), sulfametazina (SMZ) e sulfadimetoxina (SDM) em leite UHT integral. A extracao foi realizada com diclorometano e coluna de extracao em fase solida de silica. Os residuos, apos derivacao com fluorescamina, foram quantificados por cromatografia liquida de alta eficiencia com detector de fluorescencia. O limite de deteccao das tres sulfas em amostra de leite integral foi 0,3 µg L-1 e o limite de quantificacao foi 1 µg L-1 para STZ e SMZ e 2,5 µg L-1 para SDM, com coeficientes de variacao entre 4,4 e 6,6%. Os valores de recuperacao para STZ, SMZ e SDM foram 63,2, 91,2 e 63,2%, respectivamente. Considerando o limite maximo de residuo estabelecido pela legislacao brasileira de 100 µg kg-1 para a soma das concentracoes totais de STZ, SMZ e SDM, o metodo descrito permite a determinacao simultânea dos tres analitos em amostras de leite UTH integral.

Polycyclic aromatic hydrocarbons content and fatty acids profile in coconut, safflower, evening primrose and linseed oils

This study aimed at evaluating the polycyclic aromatic hydrocarbons (PAHs) contamination of commercial vegetable oils and examined the identity through the fatty acids profiles. Coconut, safflower, evening primrose, and linseed oils marketed in São Paulo (Brazil) were investigated totaling 69 samples. Four PAHs, benzo[a]anthracene (BaA), chrysene (Chr), benzo[b]fluoranthene (BbF), and benzo[a]pyrene (BaP), were detected in 96% of the samples at individual levels ranging from not detected to 14.99 μg kg-1. Chrysene was the abundant hydrocarbon found among all types of oils, with the highest median values. The results of the fatty acid profiles revealed that 43% showed different profiles according to the ones on their labels, with a higher incidence of adulteration of evening primrose oils. The maximum tolerable limits by European Regulation No. 835/2011 were exceeded for BaP in 12%, and for total 4 PAHs in 28%, with a greater contribution of adulterated samples.

Occurrence of deoxynivalenol in wheat flour, instant noodle and biscuits commercialised in Brazil

ABSTRACT A total of 134 samples, consisting of 58 wheat flour, 40 instant noodle and 36 biscuits, were analysed for the presence of deoxynivalenol (DON). The samples were obtained from retail markets of the city of São Paulo during the period 2010–2014. DON was determined by high performance liquid chromatography with ultraviolet detection and immunoaffinity sample clean-up. Method validation followed international guidelines. The LOD and LOQ were 60 and 200 µg kg−1, respectively, considering the three different types of samples analysed. The lowest recovery found in this study was 91.8% with RSD 4.5% for instant noodles. DON was detected in 91.4%, 97.5% and 97.2% of samples wheat flour, instant noodles and biscuits, respectively, resulting in a total of 94.8% with levels ranging from LOD to 1720.0 µg kg−1.