山东临沂部分地区2014年产花生真菌及黄曲霉毒素污染调查

中文：目的 对山东临沂地区五个花生主产区2014年产花生真菌及黄曲霉毒素污染情况进行调查。方法 分别采集收获前1个月的花生和土壤样品、收获期、收获后贮藏1个月及3个月的花生样品,花生和土壤真菌菌相调查分别采用点种法和稀释法接种马铃薯葡萄糖琼脂(PDA)平板,于28±1℃培养5后进行菌落计数并鉴定;黄曲霉毒素含量采用高效液相色谱法测定。结果 临沂不同地区花生和土壤样品污染的真菌菌相不同,土壤样品真菌菌相更为丰富,但黄曲霉(7%)及黄曲霉毒素(1%)污染水平均较低。结论 山东临沂部分地区花生样品受黄曲霉及黄曲霉毒素污染较轻,但仍需注意土壤中其它真菌污染,可以有效预防花生中真菌及其毒素污染和减少人类膳食暴露。     

The production of aflatoxins in fresh date fruits and under simulated storage conditions

Sixteen varieties of date fruit (Phoenix dactylifera) at three stages of maturation (Kimri, Rutab and Tamr) were examined for the presence of fungi and analysed for aflatoxins B₁, B₂, G₁ and G₂ and sterigmatocystin. Single samples of each variety were used in the study. Samples as received were initially examined for mycoflora and toxin levels and then stored at 98% relative humidity and 30 °C for 14 days to investigate the effects of possible adverse storage conditions on mycoflora and, in particular, aflatoxin formation. All samples showed an absence of aflatoxins and their precusor, sterigmatocystin, after adverse storage for 14 days, although aflatoxin‐producing Aspergillus flavus isolates were identified in 10 varieties at the first stage of maturation (Kimri). High fungal counts were associated with the Rutab stage and low counts with the Tamr stage. The counts of A flavus ranged from 5.00 to 8.16 log₁₀(cfu g^?1) under simulated storage conditions, and three varieties contained significant levels of aflatoxin B₁ or B₂ ranging from 35 to 11 610 µg kg^?1. Sterigmatocystin was not detected in any of the samples as received or under simulated storage conditions. © 2002 Society of Chemical Industry     

Aflatoxin determination in peanut butter by enzyme-linked immunosorbent assay

High specificity, high titre antisera to aflatoxins B₁ and G₁ have been produced by immunisation of rabbits with a bovine serum albumin-aflatoxin B₁ conjugate. The antiserum has been used to set up an indirect, double antibody microtitration plate enzyme-linked immunosorbent assay with a limit of detection of 0.1 pg toxin per well. The assay has been validated for application to peanut butter, and demonstrates many advantages over conventional methodology, including the requirement for minimal sample preparation before assay, its technical simplicity, and its potential high sample through-put.     

牛奶及奶粉中黄曲霉毒素M1的快速测定

采用免疫亲和柱－荧光光度法快速测定了牛乳及乳制品中黄曲霉毒素M1。试样经过离心、脱脂、过滤后滤液经过键合有黄曲霉毒素M1特殊抗体的免疫亲和柱净化，此抗体对黄曲霉毒素M1具有专一的识别能力，黄曲霉毒素M1键合在分离柱中的抗体上，用甲醇与水之比为10：90的混合液将免疫亲和柱上杂质除去；以甲醇与水之比为80：20的混合液通过分离柱洗脱；加入溴溶液衍生，以提高测定灵敏度，衍生化后的洗脱液于荧光光度计中测定黄曲霉毒素M1，检测低限为0．1μg/kg；在0．1－1．0μg/kg范围内，回收率为89．6％－96．1％，变异系数为0．52％－5．8％，分析一个样品的时间小于30min，分析过程中不使用黄曲霉毒素M1标准物质，结果表明，本方法具有准确、简单、快速、安全等优点，可以满足少量和批量样品的检测需要。     

吲哚对黄曲霉生长及产毒的抑制作用

本文研究了吲哚对黄曲霉的生长以及产毒的抑制作用。通过96孔板微量法发现吲哚能够抑制黄曲霉的生长,其最小抑制浓度(MIC)为100μg/m L;进而采用差量法测定了吲哚对黄曲霉菌丝生长量的抑制作用,结果表明200μg/m L的吲哚处理可以完全抑制黄曲霉的菌丝生长。此外,通过高效液相色谱分析发现吲哚浓度达到50μg/m L时,尽管对菌丝生长量没有明显影响,但是可以有效地抑制黄曲霉毒素B1的产生。这些结果说明吲哚抑制毒素产生并不是通过抑制生长来实现的。为了进一步了解吲哚对毒素产生的抑制机制,本研究通过RT-PCR分析了吲哚对黄曲霉产毒相关基因表达的影响。结果显示吲哚对产毒调控基因afl R的影响与其对毒素的作用趋势相同,同时吲哚还能够下调其他一些产毒相关基因afl K和alf D的表达。我们的研究结果表明吲哚具有很高的开发价值应用于粮食和饲料中黄曲霉毒素污染的控制。     

基于氧化石墨烯的荧光适配体传感器检测食品中真菌毒素

目的：利用核酸适配体（aptamer,APT）和氧化石墨烯（graphene oxide,GO）组装一种基于荧光共振能量转移原理的荧光适体传感器,用于两种真菌毒素的同时检测。方法：GO通过π-π堆积作用将荧光标记的黄曲霉毒素B1（aflatoxin B1,AFB1）APT1和伏马毒素B1（fumonisin B1,FB1）APT2吸附在其表面。由于荧光共振能量转移效应,APT上荧光基团的荧光被GO猝灭;当向溶液中加入靶标AFB1和FB1时,APT1和APT2分别与AFB1和FB1结合,从GO中游离出来,恢复荧光。结果：该传感器为AFB1和FB1的荧光检测提供快速、灵敏的方法,AFB1的检出限为0.15?ng/mL,FB1的检出限为0.12?ng/mL。同时对白酒样品进行加标回收实验,回收率分别为92.00%～100.81%（AFB1）和89.00%～99.50%（FB1）。结论：本研究构建的荧光APT传感器用于两种真菌毒素的同时检测具有高灵敏度和特异性,同时该APT传感器同样适用于其他真菌毒素的多重检测。     

乳品中黄曲霉毒素M1检测方法研究进展

黄曲霉毒素M1是动物摄入黄曲霉毒素B1后的代谢产物,主要分布在动物的乳汁、尿液中。黄曲霉毒素M1毒性很大,经乳制品摄入会对人体产生巨大的危害。本文主要对乳品中黄曲霉毒素M1毒性、危害、检测方法进行综述。对主要检测方法的特性及适用范围进行分析与概括,并且对未来黄曲霉毒素M1的检测方法的发展进行了合理展望。     

时间分辨荧光免疫层析法定量检测谷物中黄曲霉毒素B1和玉米赤霉烯酮残留

建立了一种快速定量检测谷物产品中黄曲霉毒素(Aflatoxin B1,AFB1)和玉米赤霉烯酮(Zearalenone,ZEN)的时间分辨荧光免疫层析方法。采用时间分辨荧光微球标记黄曲霉毒素B1抗体和玉米赤霉烯酮抗体,研究了如p H值、标记抗体浓度、荧光探针使用量、检测T线包被原浓度、质控C线羊抗鼠Ig G浓度、样品前处理方法等因素对时间分辨荧光免疫层析方法灵敏度的影响。结果表明:AFB1的检出限为0.80 ng/mL,线性范围(IC20~IC80)为0.81~5.67 ng/mL,半抑制浓度(IC50)为2.15 ng/mL。在ZEN检出限为4.58 ng/mL,线性范围(IC20~IC80)为4.76~85.60 ng/mL,半抑制浓度(IC50)为20.19 ng/mL。方法特异性良好,与T-2毒素、脱氧雪腐镰刀菌烯醇、伏马毒素、赭曲霉毒素A多种真菌毒素交叉率小于10%。通过选择玉米、麦麸、大豆、小麦进行添加回收试验,AFB1的添加回收率在97.1%~108.7%之间,ZEN的添加回收率在92.8%~109.1%之间,相对标准偏差小于15%。选取经HPLC-MS/MS检测过的FAPAS标准质控样本进行测试,检测结果与其结果一致。在实际产品检测对比中,与市售胶体金免疫层析卡,ELISA试剂盒的检测结果基本一致。本方法操作简单快速、可定量,检测过程约25 min,适用于谷物样品中黄曲霉毒素B1和玉米赤霉烯酮的现场快速筛。     

Comparison of Antimutagenic Activity of Phenolic Compounds in Newly Harvested and Stored Common Beans Phaseolus vulgaris against Aflatoxin B1

ABSTRACT: Phenolic compounds were extracted from recently harvested or stored black Jamapa beans ( Phaseolus vulgaris ) that were subjected or not to thermal treatment. The beans studied were cropped in the same area and were from the same lot. The highest amount of condensed tannins (CT) was found in the seed coat of recently harvested beans [222.41 ± 16mg of (+)-catechin equivalents per gram of seed coat]. After 2 yof storage, the amount of CT dropped significantly [35.8 ± 3.4 mg of (+) -catechin equivalents per gram of seed coat]. Thermal treatment significantly reduced the amount of CT in whole beans by approximately 70%. The raw seeds contained 13.76 ±1.2 mg of (+)-cat-echin equivalents per gram of seeds and a portion of CT appeared in the broth [9.4 ± 0.1 mg of (+) -catechin equivalents per gram of lyophilized broth]. The antimutagenic activity of these extracted phenolic compounds was tested against aflatoxin B₁ (AFB₁) in the Kado microsuspension assay. Newly harvested beans showed higher antimutagenic activity against AFB₁ mutagenicity than stored beans. The results suggest that to take the maximum advantage of components with biological activity present in beans, they must be used fresh.