Validation of analytical parameters of a competitive direct ELISA for aflatoxin B1 in peanuts

Analytical validation of a competitive direct SUNQuik ELISA with a reference High Performance Liquid Chromatography (HPLC) method and other methods including a minicolumn method and the VICAM Aflatest® system for aflatoxin in peanuts was conducted. Both the ELISA and the VICAM Aflatest® system, using the same peanut extracts were analytically comparable with the HPLC method (R=0.998, p<0.000). The minicolumn method was also found to be acceptable as a low cost rapid semi-quantitative test. Despite the large variation in sampling, the correlation between the SUNQuik ELISA and HPLC using the different peanut sub-samples was considered acceptable over the range of 0–1200 µg kg^?1 (R=0.938). No false negatives were found using the SUNQuik ELISA and false positives were either nil or negligible in all the studies conducted. The repeatability of the SUNQuik ELISA run on the same day was good with only±10% deviation. The reproducibility of the SUNQuik ELISA between days was also acceptable, but with a higher deviation. Applying the SUNQuik ELISA for aflatoxin surveys of peanuts in Indonesia proved that the method can deliver high quality, cost- and time-effective analysis with very little establishment capital and maintenance.     

Evaluation of a method to determine the natural occurrence of aflatoxins in commercial traditional herbal medicines from Malaysia and Indonesia

Traditional herbal medicines, popularly known as ‘jamu’ and ‘makjun’ in Malaysia and Indonesia, are consumed regularly to promote health. In consideration of their frequent and prolonged consumption, the natural occurrence of aflatoxins (AF) in these products was determined using immunoaffinity column clean-up and high-performance liquid chromatography with pre-column derivatization. The evaluated method, which entails dilution of sample extracts with Tween 20–phosphate buffered saline (1:9, v/v) and a chromatographic system using isocratic mobile phase composed of water–methanol–acetonitrile (70:20:10, v/v/v), was effective in separating AFB₁, AFG₁ and AFG₂ from interference at their retention times. Results were confirmed using post-column derivatization with photochemical reactor. For 23 commercial samples analyzed, mean levels (incidence) of AFB₁, AFB₂ and AFG₁ in positive samples were 0.26 (70%), 0.07 (61%) and 0.10 (30%) μg/kg, respectively; one sample was positive for AFG₂ at a level of 0.03 (4%) μg/kg. In contrast to the high levels of AF in crude herbal drugs and medicinal plants reported previously by other researchers, the low contamination levels reported in this study may be attributed to the higher selectivity to AF of the method applied. Based on the AFB₁ levels and the daily consumption of positive samples, a mean probable daily intake of 0.022 ng/kg body weight was calculated.     

Ultra-high-pressure liquid chromatography–solid-phase clean-up for determining aflatoxins in Egyptian food commodities

In this work, we determined the content of regulated aflatoxins (ATs) B1, B2, G1, and G2 in food commodities using solid-phase extraction (SPE) and ultra-high-pressure liquid chromatography with fluorescence detection without derivatization. We extracted ATs from the ground samples by mixing in NaCl and 80% (v/v) methanol. The sample was enriched and cleaned up by SPE technique using Bakerbond^® C18 cartridges. The extract that we obtained was immediately analyzed using isocratic elution with a mobile phase consisting of acetonitrile, methanol and deionized water in a ratio of 64:18:18. Method validation was carried out by determining these ATs in a quality control material consisting of almond T02445QC and with the add-found test. The results provided satisfactory recovery within the range of 89.6–103.3%. Repeatability and intermediate precisions were assessed as RSD (%) which were found in the range of 1.1–11.3% and 1.5–12.0%, respectively. The limit of detection (S/N = 3) was 0.03, 0.02, 0.04, and 0.02 μg kg⁻¹ for B1, B2, G1 and G2, respectively. Finally, the method was successfully applied to determine ATs in raw Egyptian food commodities, namely maize, popcorn, pistachio, corn, peanuts, chilli, wheat, green coffee and almond, and the corresponding RSD did not exceed 11%.     

Risk analysis of main mycotoxins occurring in food for children: An overview

Mycotoxins are secondary metabolites produced by fungi contaminating the food chain that are toxic to animals and humans. Children up to 12 years old are recognized as a potentially vulnerable subgroup with respect to consumption of these contaminants. Apart from having a higher exposure per kg body weight, they have a different physiology from that of adults. Therefore they may be more sensitive to neurotoxic, endocrine and immunological effects. For these reasons, a specific and up-to-date risk analysis for this category is of great interest.In this review, an accurate analysis of the main mycotoxins occurring in food intended for children (deoxynivalenol, aflatoxins, ochratoxins, patulin and fumonisins) is presented. In particular, known mechanisms of toxicity and levels of exposure and bioaccessibility in children are shown. In addition, recent discoveries about the strategies of mycotoxins managing are discussed.     

部分省市食用植物油中黄曲霉毒素B1的调查分析

目的了解我国食用植物油中黄曲霉毒素B1的污染状况。方法2011年对我国部分省（区、市）不同销售场所出售的各类食用植物油中黄曲霉毒素B1含量进行调查,通过对数据进行统计分析后进行评价。结果从食用油种类分析,花生油和玉米油黄曲霉毒素B1含量最高,分析可能与其原料有关。从采样时间分析,夏季生产的产品黄曲霉毒素B1含量高于其他季节的产品。从样本包装类型分析,散装油黄曲霉毒素B1含量明显高于定型包装产品。结论食用植物油产品中存在黄曲霉毒素B1污染的现象,且与油的种类、生产日期等条件有关。     

A Modified Liquid Medium for Higher Production of Aflatoxins

Summary: A modified synthetic liquid medium for the production of aflatoxin was evaluated. The medium stimulated a higher production of aflatoxins expecially B₁. The substitution of glucose with sucrose resulted into a significant increase in the production of the toxic metabolite. It seemed that sucrose provided a superior source of energy and carbon atoms that are needed by the fungus for the conversion of nutrients into secondary metabolites under the used condition.
Zusammenfassung: Ein modifiziertes synthetisches flüssiges Nährmedium wurde für die Aflatoxin-Produktion erprobt. Das Nährmedium stimulierte eine höhere Toxinbildung besonders von Aflatoxin B₁. Der Ersatz von Glukose durch Sukrose führte zu einer signifikanten Zunahme in der Toxinbildung. Es schien, daß Sukrose eine bessere Quelle für Energie und Kohlenstoffatome darstellt, die der Pilz für die Umformung der Nährstoffe zu Metaboliten benötigt.     

Determination of aflatoxins in imported rice to Iran

Aflatoxins (AFs) are highly toxic and carcinogenic secondary fungal metabolites and have been detected in various food commodities including cereals. Rice were imported to Iran during March 2006–March 2007 analyzed for aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1) and aflatoxin G2 (AFG2) using immunoaffinity column and quantitated by HPLC. In this regard, 71 rice samples were collected. After dividing samples to sub-samples, AF analyses were done. Among 71 samples analyzed, AFB1 was detected in 59 samples (83% of the total). The mean of AFB1 was 1.89 ng/g for all samples (with the not detected samples taken as zero). Total AF (AFT) was detected in 59 samples (83% of the total). The mean of AFT was 2.09 ng/g for all samples. AFB1 level in two samples (2.8%) was above the maximum tolerated level (MTL) of AFB1 in Iran (5 ng/g). Regarding AFT, the mean contamination level (2.09 ng/g) was lower than MTL of AFT in rice in Iran as well as lower than maximum level of EU for AFT (4 ng/g), and only nine samples had levels above the MTL of EU in AFT.     

米甜酒中氨基酸和黄曲霉毒素的分析

米甜酒为糯米发酵而得的低醇甜酒,民间饮用普遍。为考察其营养成分,本文用纸层析方法进行了米甜酒的氨基酸分析,从中分离和鉴定了精氨酸(Arginine),瓜氨酸(Citrulline),苏氨酸(Threonine),丝氨酸(Serine),酪氨酸(Tyrosine),苯丙氨酸(Phenylalanine),     

Towards internationally acceptable standards for food additives and contaminants based on the use of risk analysis

Internationally acceptable norms need to incorporate sound science and consistent risk management principles in an open and transparent manner, as set out in the Agreement on the Application of Sanitary and Phytosanitary Measures (the SPS Agreement). The process of risk analysis provides a procedure to reach these goals. The interaction between risk assessors and risk managers is considered vital to this procedure. This paper reports the outcome of a meeting of risk assessors and risk managers on specific aspects of risk analysis and its application to international standard setting for food additives and contaminants. Case studies on aflatoxins and aspartame were used to identify the key steps of the interaction process which ensure scientific justification for risk management decisions. A series of recommendations were proposed in order to enhance the scientific transparency in these critical phases of the standard setting procedure.