Occurrence of aflatoxins B 1 , B 2 , G 1 and G 2 in some Brazilian pet foods

The presence of cereals and grains in the formulation of pet foods suggests the need to control aflatoxin contamination in these foods. The objective of the study was to analyse domestic pet food to determine the occurrence of aflatoxins as well as their risk to animal health. One hundred food samples (45 for dogs, 25 for cats, 30 for birds) were collected at random from pet shops in Alfenas city, south-east Brazil. Thin-layer chromatography was used for separation, identification and quantification of the compounds after validation of the method. Aflatoxins were detected in 12.0% of the samples. Levels of aflatoxins (B 1 + B 2 + G 1 + G 2 ) above the maximum limit established in Brazil (50 µg kg -1 ) for animal food were detected in five of the 12 positive samples (41.7%). The concentration of total aflatoxins was 15-374 µg kg -1 (mean 131 µg kg -1 ). All samples containing peanuts were positive for aflatoxin B 1 . Aflatoxins are carcinogenic and their consumption might be a risk for domestic animal health. The high prevalence of aflatoxin B 1 in foods prepared for birds, species highly susceptible to aflatoxins, shows the need for the re-evaluation of the use of peanuts (present in seven of the eight samples positives for aflatoxin) and/or the addition of fungicides to the food.     

Heterocyclic amines in some Swedish cooked foods industrially prepared or from fast food outlets and restaurants

Accurate assessment of human intake of mutagenic/carcinogenic heterocyclic amines (HAs) is necessary for epidemiological studies and future risk assessment. Using questionnaires, the frequency of consumption of specific dishes can be obtained at an individual level and linked to analyzed concentrations of different compounds in corresponding dishes. Some typical Swedish cooked meat dishes, hamburgers and kebab, industrially prepared or from fast food outlets and restaurants, were analyzed regarding their content of 11 different HAs. The amount of each of these compounds was below 0.1 ng/g cooked weight in most of the industrially prepared products. The total amount of HAs was highest in the kebab samples. The intake of HAs from 200 g of the dishes was estimated to range from not detectable levels to 0.6 microg. The results of the present study indicate that the content of HAs in a specific dish may vary with origin, and that the concentrations of HAs in commercial fried meat products are generally low, although some of these food items may contain elevated amounts.     

Co-occurrence of aflatoxins B 1 , B 2 , G 1 , G 2 , zearalenone and fumonisin B 1 in Brazilian corn

Two hundred and fourteen unprocessed corn samples (1997-98 harvest), collected at wholesale markets in different regions in Brazil, were surveyed for the occurrence of mycotoxins. The samples were analysed for aflatoxins B 1 , B 2 , G 1 , G 2 , zearalenone and fumoni1sin B 1 using in-house validated methods. The occurrence of aflatoxin B 1 , zearalenone and fumonisin B 1 was found in 38.3, 30.4 and 99.1% of the samples, respectively. Aflatoxin B 1 , zearalenone and fumonisin B 1 contamination levels varied from 0.2 to 129, 36.8 to 719, and 200 to 6100 μg/kg, respectively. The cooccurrence of the two carcinogenic mycotoxins aflatoxin B 1 and fumonisin B 1 was observed in 100% of the aflatoxin-contaminated samples (82 samples). Cooccurrences of aflatoxin B 1 : zearalenone: fumonisin B 1 and aflatoxin B 1 : aflatoxin B 2 : fumonisin B 1 were found in 18 and 43 samples, respectively.     

Occurrence of aflatoxins B1, B2, G1, and G2 in peanuts and their products marketed in the region of Campinas, Brazil in 1995 and 1996.

Samples of peanuts and their products marketed in the region of Campinas, Brazil in 1995 and 1996 were analysed in terms of aflatoxin B1, B2, G1, and G2 by thin-layer chromatography, aiming at the protection of consumer health. Of the 80 samples analysed, 35 of peanuts and 45 of peanut products, 41 (51%) presented contamination with aflatoxin, 11 of them being peanuts (27%) and 30 being products (67%), in a range of 43 to 1099 micrograms/kg for B1 + B2 + G1 + G2 with a 90th percentile of 415 (B1 + G1) and of 615 (B1 + B2 + G1 + G2). The results also demonstrated that aflatoxin B1 (AFB1) reached the highest incidence and the highest upper limits compared with all the other aflatoxins.     

食品中黄曲霉毒素B1、B2、G1、G2的高效液相色谱测定方法

为建立同时测定食品中黄曲霉毒素B1、B2、G1、G2的高效液相色谱测定方法，将碾磨后的试样经乙腈＋水溶液提取、过滤后，以MycoSep^TM净化柱净化，吹干净化液后，加入正己烷和三氟乙酸溶液衍生，反相色谱柱测定。黄曲霉毒素B1、B2、G1、G2能达到完全的基线分离，检出限分别为0．012、0．008、0．036和0．024μg／kg，不同水平的加标回收率均达80％以上，RSD均小于3．0％。该方法快速、准确、灵敏，有利于试验者安全，能同时分离食品中黄曲霉毒素B1、B2、G1、G2。     

Occurrence of aflatoxins (B1, B2, G1, G2) in herbal tea consumed in Turkey

Aflatoxin contents in 12 types of herbal teas were determined by high performance liquid chromatography (HPLC) with fluorescence detector using immunoaffinity column clean-up. Forty eight samples were collected from four local herbal shops in Manisa, Turkey. Of the 48 samples analyzed, 43 were aflatoxin positive. The highest concentration of aflatoxin (34.18 µg/kg) was determined in a sample of camomile tea. The occurrence of AFB1, B2, G1 and G2 was found in samples at levels of 54, 29, 71 and 46 %, respectively. Aflatoxin B1, B2, G1 and G2 contamination levels varied from 0 to 14.2, 0 to 12.4, 0 to 13.5 and 0 to 28.7 µg/kg, respectively. Aflatoxin was not detected in five samples consisting of linseed, lime and fennel tea.     

Determination of aflatoxins B1 and B2 by adsorptive cathodic stripping voltammetry in groundnut

In this study, adsorptive stripping voltammetry was proposed for determination of aflatoxins B1 (AFB1) and B2 (AFB2) using hanging mercury drop electrode (HMDE) as the working electrode. Both aflatoxins were found to adsorb and undergo irreversible reduction reaction at the working mercury electrode. The experimental conditions were optimised by one-at-a time and experimental design to obtain the best characterised peak in terms of peak height with analytical validation of the method for each aflatoxin. The calibration curves for aflatoxins AFB1 and AFB2 were linear in the ranges of 0.4–40 ng ml⁻¹ and 0.2–70 ng ml⁻¹ with the limit of detections (LOD) 0.15 and 0.10 ng ml⁻¹, respectively. The proposed method was applied for the analysis of aflatoxins in groundnut samples and the results were compared with those obtained by the HPLC technique.     

Investigation of various extractants for the analysis of aflatoxin B1 in different food and feed matrices

Various extractants were investigated concerning their suitability for aflatoxin B₁ determinations in different matrices including spices, infant formula and animal feed employing an immunoaffinity clean-up procedure. It was shown that the use of aqueous acetonitrile extractants was limited due to the fact that dry sample material can absorb significant amounts of water from theextractant. This canresultin recoveries thataretoo high and therefore in incorrect values for the aflatoxin concentration if aliquots are taken for further analysis. Acorrection of theresultsby recovery calculationusing spiked blank materialis unsuitable, since material from the same group of food (e.g. paprika powder) or feed can vary significantly in the recovery values. Therefore it is recommended that aqueous methanol extractants are used, since no significant interaction with matrix constituents was observed. In addition,aqueous acetone extractants are a useful alternative with some limitations.     

柱前衍生-高效液相色谱法检测食品中的黄曲霉毒素B_1、B_2、G_1、G_2

目的:改进柱前衍生-高效液相色谱法测定食品中的黄曲霉毒素B1、B2、G1、G2。方法:分别用甲醇-水(8∶2,v∶v)或二氯甲烷提取食品中的黄曲霉毒素。提取液经免疫亲和柱净化后,采用三氟乙酸(或甲酸)进行衍生,并利用高效液相色谱仪进行测定。结果:黄曲霉毒素B1、B2、G1、G2的检出限分别为0.2、0.2、0.2、0.2μg/kg;在低、中、高加标浓度下的回收率分别为81.0%~94.1%、75.6%~92.0%、75.0%~92.4%、77.6%~91.3%。结论:改进后的柱前衍生-高效液相色谱法克服了样品基质的干扰,测定结果更准确。     

Aflatoxins in Foods and Feedstuffs. Part 3. Fluorodensitometric method for determination of aflatoxins M1 and M2 in presence of aflatoxins B1, B2, G1 and G21

The method of aflotoxins M₁ and M₂ determination in presence of aflatoxins B₁, B₂, G₁ and G₂ is presented. The fluorescence properties of aflatoxin M₁ and M₂ are discribed. A simple method of aflatoxin M extraction is proposed. Results of different tests for confirmation of aflatoxins M are discussed. During control of powdered milk from three factories aflatoxins M were not detected in final products.     

Kinetic modelling of aflatoxins B1 conversion and validation in corn,rice, and peanut during thermal treatments

A kinetic model of the aflatoxins B₁ conversion was plotted and validated successfully in the aflatoxin B₁-contaminated rice during thermal treatments. Specifically, the kinetic Model A and Model B of the aflatoxin B₁ conversion were plotted based on the differential-scanning calorimetry and thermogravimetric analysis, respectively, with the pure aflatoxin B₁. In succession, Model A and Model B were validated in the aflatoxin B₁-contaminated corn, rice, and peanut during thermal treatments. Model A successfully simulated the conversion of aflatoxin B₁ in the aflatoxin B₁-contaminated rice with the correlation coefficients of 0.859 and average-absolute deviation of 6.61. The activation energy and conversion order of the aflatoxin B₁ conversion were 89.0 kJ/mol and 0.12, respectively. Moreover, the relationships between the conversion degree and time vs temperature were plotted based on Model A. These plots would help to predict the final content of aflatoxin B₁ after thermal treatments, and give an instruction to develop a food processing.     

Occurrence of aflatoxins M(1) and M(2) in milk commercialized in Ribeir?o Preto-SP, Brazil.

Aflatoxins are toxic metabolites found in foods and feeds. When ruminants eat foodstuffs containing aflatoxins B(1) and B(2), these toxins are metabolized and excreted as aflatoxin M(1) and M(2) in milk. The aim was to determine the incidence of these aflatoxins in commercial milk collected from supermarkets in Ribeir?o Preto-SP, Brazil, and consisting of 60 ultrahigh temperature (UHT) milk samples and 79 pasteurized milk samples. The milk samples were analysed according to method 986.16 of AOAC International. None of the milk samples analysed were contaminated with aflatoxin M(2), and aflatoxin M(1) was detected in 29 (20.9%) of samples in the range 50-240 ng l(-1). The results show that despite a high occurrence of aflatoxin M(1) in commercial pasteurized and UHT milk sold in Ribeir?o Preto in 1999 and 2000, the contamination level of these toxins could not be considered a serious public health problem according to MERCOSUR Technical Regulations. However, levels in 20.9% of the milk samples exceeded the concentration of 50 ng l(-1) permitted by the European Union. Although it is not necessary to continue monitoring the incidence and levels of aflatoxins M(1) and M(2) in milk samples, surveillance could be appropriate.     

Occurrence of aflatoxin B1, citrinin and ochratoxin A in rice in five provinces of the central region of Vietnam

The possible coexistence of three mycotoxins in rice, including aflatoxin B1 (AFB1), citrinin (CIT) and ochratoxin A (OTA), was investigated. The samples of rice were collected in large markets in five provinces of the central region of Vietnam. These toxins were extracted, purified and finally quantified by HPLC with fluorimetry detection. Contamination of AFB1 was found to be the most, followed by OTA, while contamination of CIT was insignificant. The coexistence of CIT with AFB1/OTA in rice was found in high percentage. Some samples overpassed the authorized limit by Europe in OTA and/or AFB1.     

Validation of a confirmatory analytical method for the determination of aflatoxins B1, B2, G1 and G2 in foods and feed materials by HPLC with on-line photochemical derivatization and fluorescence detection

A sensitive and selective analytical method for the simultaneous separation and quantitative determination of aflatoxins B₁, B₂, G₁ and G₂ in foodstuffs and materials for feed has been validated. The method is based on high performance liquid chromatography with on-line post-column photochemical derivatization and fluorescence detection. The chromatographic separation of aflatoxins was accomplished using a C₁₈ column eluted with an isocratic mobile phase consisting of water, methanol and acetonitrile. The sample preparation required a simple extraction of aflatoxins with MeOH/H₂O (80:20, v/v) and a purification step by immunoaffinity column cleanup. The total analysis time, including sample preparation and chromatographic separation, did not exceed 40 min with a run time of 10 min. The on-line photochemical derivatization ensures better results in terms of simplicity, sensitivity and reproducibility with respect to chemical derivatization techniques, and provides an increase of the peak resolution and an extent of automation in comparison with the electrochemical ones. The procedure for the determination of aflatoxins in food samples and cereals for animal consumption was extensively validated following Regulation (EC) No. 882/2004. Detection limits in wheat bran samples of 0.08 µg kg^?1 for AFB₁, 0.02 µg kg^?1 for AFB₂, 0.16 µg kg^?1 for AFG₁ and 0.04 µg kg^?1 for AFG₂ were attained. The method allows high recovery with mean values ranging from 72 to 94% and it satisfies the necessary requirements for sensitivity, linearity, selectivity, precision and ruggedness, demonstrating the conformity of the method with provisions of Regulation (EC) No. 401/2006.     

高效液相色谱-串联质谱法同时测定花生制品中的黄曲霉毒素B1、B2、G1、G2

采用高效液相色谱-串联质谱建立了高效液相色谱-串联质谱法同时测定花生制品中4种黄曲霉毒素(B1、B2、G1、G2)的方法.结果表明,在ESI正离子模式下,高效液相色谱-串联质谱法的最低检出限为0.2μg/kg,定量限为0.6 μg/kg;标准工作液在0.5～50.0μg/kg的范围内线性良好,相关系数达到0.9990.     

高效液相色谱-荧光法与高效液相色谱-二极管阵列法测定食品中维生素B1含量的比较研究

目的比较研究GB 5009.84-2016中高效液相色谱-荧光法(high performance liquid chromatography-fluorescence method,HPLC-FLD)和GB/T 5009.197-2003中高效液相色谱-二极管阵列法(high performance liquid chromatography–diode array method,HPLC-DAD)检测食品中维生素B_1含量的适用性。方法以实验室常见样品奶粉(基质相对复杂)和维生素原料粉(基质简单)为研究对象,分别采用HPLC-FLD法与HPLC-DAD法对其维生素B_1含量进行测定。HPLC-FLD法中样品经过水解、酶解过夜、萃取过滤后经HPLC分析;HPLC-DAD法中样品经溶解、离心、过滤后经HPLC分析。结果 2种方法在各自线性范围内,线性关系均良好(r=0.9995、0.9994),回收率范围分别为92.8%~101.6%和106.3%~109.9%,均能满足检测要求。对于基质相对简单、维生素B_1含量较高的食品,HPLC-DAD法的检测结果更为准确,重现性好且更接近样品声称值;对于基质较为复杂的食品,HPLC-DAD法的检测结果与HPLC-FLD法相差不大。结论 HPLC-DAD法操作简便、准确度高、精密度好,是测定食品中维生素B_1含量的可行方法,能够缩短检验时间,提高检验效率,具有较好的实用价值。     

Aflatoxins in Foods and Feedstuffs. Part 2. Determination of the aflatoxin B1, B2, G1 and G2 contents in Grain crops1

The simple method for determination of small amounts of aflatoxins (about 5–10 μg/kg) was described. The method was adopted for wheat, barley, rye and oats. Difficulties of aflatoxins determination in cereals are discussed, mainly observed during purification of extracts and resolution by TLC. Different tests were compared for confirmation of aflatoxins in cereals. Results of cereal crops control for contamination with aflatoxins are presented.     

Aflatoxin M(1) and ochratoxin A in a human milk bank in the city of S?o 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, S?o 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 S?o Paulo.