Comparison of two Analytical Methods (ELISA and LC-MS/MS) for Determination of Aflatoxin B1 in Corn and Aflatoxin M1 in Milk

The aim of this paper is to assess the closeness of agreement between results of ELISA and LC-MS/MS methods for determination of aflatoxin B₁ in corn and aflatoxin M₁ in milk. Samples of corn (n=100) and milk (n=250) were simultaneously analyzed using ELISA and LC-MS/MS methods, after the severe drought that affected Serbia in summer 2012 resulting in occurrence of aflatoxin B1 in corn and aflatoxin M₁ in milk. Regression analysis showed higher level of agreement between aflatoxin B₁ samples (R²=0.994), compared to aflatoxin M₁ samples (R²=0.920). However, both techniques were satisfactory in meeting the requirements for official control purposes.     

液相色谱-串联质谱法测定植物油中黄曲霉毒素B1的含量

目的:建立植物油中黄曲霉毒素B1含量的液相质谱-串联质谱测定方法。方法:采用液相色谱-串联质谱法（LC-MS/MS）,以乙腈为溶剂提取植物油中黄曲霉毒素B1。ZORBAX SB-C18（2.1mm×50mm,1.8μm）色谱柱,流动相为乙腈-0.2%甲酸（40∶60）梯度洗脱,流速为0.3mL/min,进样量为5μL。采用电喷雾离子化四极杆串联质谱,多反应监测方式测定样品的浓度。检测离子对分别为m/z 313.0→285.0和m/z 313.0→241.0。结果:黄曲霉毒素B1进样量在0.204⁴.08ng/mL（r=0.9991）范围内呈良好的线性关系,平均加样回收率为98.15%,RSD=1.12%（n=9）。结论:该法简便快捷、结果准确,可用于植物油中黄曲霉毒素B1的含量的测定。      

Assessment of Groundnut Varietal Tolerant to Aflatoxin Contamination in Indonesia

Aflatoxin is secondary metabolite produced by Aspergillus flavus and A. paraciticus that grow on the seed coat (testa) of groundnut. This toxin is a serious food safety issue throughout the world. The availability of resistant genotype to A. flavus infection and/or aflatoxin contamination urgently needed. The experiment found one genotype had aflatoxin contamination under the safe level (≤ 10 ppb), with <15% of seed number infected by A. flavus. Recently, the biggest peanut industry, where the main production is roasted-peanut (in shell) produced from fresh pods, grows and develops that variety.     

粮油食品中黄曲霉毒素去除方法研究进展

黄曲霉毒素广泛存在于粮油食品中,给全球农作物生产造成巨大经济损失。黄曲霉毒素具有极强的毒性和致癌性,严重威胁着人类的健康,迫切需要寻找一种有效、安全、环保控制黄曲霉生长或降解黄曲霉毒素的方法。对物理方法、化学方法和生物方法抑制黄曲霉生长或降解黄曲霉毒素的研究进行了综述。     

Aflatoxin M1 in raw,UHT milk and dairy products in Sicily (Italy)

A survey on 73 milk samples from different animal breeds and 24 dairy products samples from Sicily, Italy, was carried out for the presence of aflatoxin M₁ (AFM1) by LC-fluorescence detection after immunoaffinity cleanup. AFM1 was detected in 48% and 42% of the milk and dairy samples at concentration ranges between <5.0–16.0 and <5.0–18.0 ng L^?1, respectively. Within the raw milk samples, 92% had an AFM1 content below 5.0 ng L^?1, in 7% of the cases it was in the range 5.0–10.0 ng L^?1 and 1% was contaminated between 10.0 and 20.0 ng L^?1. For the dairy products, ultra-high-temperature treated (UHT) milk, milk cream and cheese, the incidence was 42%, of which 83% contained less than 5.0 ng L^?1 and 17% contained 10.0–20.0 ng L^?1 AFM1. The levels of contamination found justify continuous monitoring for public health and to reduce consumer exposure.     

Aflatoxin B1 and aflatoxins in ground red chilli pepper after drying

In this study, 180 red chilli pepper (RCP) berry samples were obtained from two different croplands of Gaziantep and Kahramanmara? (Turkey) in August, September and October. RCP berry samples were dried under sunlight and grinded. Ground red chilli pepper (GRCP) samples were analysed for aflatoxins (AFs, sum of B₁, B₂, G₁ and G₂) and AFB₁ contamination. According to the results, in 49 of 180 samples, AFB₁ and in 37 samples, AFs were higher than legal limits. The lowest amounts of AFs and AFB₁ were obtained in August and the highest amounts in October. χ² analysis showed that there were no significant differences (p > 0.05) between cities among 3 months according to number of samples with AFs and AFB₁ above legal limits. According to the Duncan multiple-range test, there was no significant difference between all months. Strict measures are necessary to produce high-quality GRCP. RCP berry must be treated to reduce moulds before production of GRCP.     

不产毒黄曲霉菌对产毒黄曲霉菌产毒抑制效果分析

本实验6株菌分离自广东、山东、辽宁和湖北四省的花生土壤中,通过形态学和分子生物学鉴定均为黄曲霉菌,HPLC测定其产毒能力,其中GZ-6为产毒菌,GZ-15、WF-5、WF-20、JZ-2和YC-8为不产毒菌。分别以花生和玉米为培养基,将不产毒黄曲霉菌和产毒菌(孢子浓度:104:105或105:105)进行混合培养,测定不产毒菌对产毒黄曲霉产毒的抑制效果。结果显示:不产毒菌对产毒菌产毒的抑制率随着其孢子浓度的增加而明显加强,当孢子浓度比为105:105(不产毒菌:产毒菌)时,5株不产毒菌在玉米培养基上对产毒菌产毒的抑制率为34.55%~75.94%,在花生培养基上对产毒菌产毒的抑制率为38.03%~83.03%,其中WF-5、WF-20和GZ-15这三株不产毒菌对产毒黄曲霉产毒的抑制效果均达到75.00%以上,可以作为田间防治黄曲霉毒素污染的候选菌株。     

Aflatoxin contamination of consumer milk caused by contaminated rice by‐products in compound cattle feed

BACKGROUND: Elevated levels of aflatoxin M1 were observed in routine checks of consumer milk in southern Sweden in early 2006. A trace‐back study revealed contaminated milk from several farms, and a total of 68 farms were banned from delivering milk to dairies for shorter or longer periods. The maximum level of aflatoxin M1 in a single sample from an individual farm was 257 ng kg^?1 fresh milk. RESULTS: Aflatoxin analyses of commercial compound feed revealed that the contamination originated from the ingredient rice feed meal, a by‐product from the preparation of Basmati rice for human consumption. Up to 56 µg kg^?1 of aflatoxin B1 was found in rice feed meal at one feed mill. CONCLUSION: The present example shows that an aflatoxin‐contaminated minor feed ingredient included at less than 10% (w/w) of compound cattle feed can significantly contaminate the milk produced. This emphasises the need for effective monitoring of the feed chain of food‐producing animals in order to prevent food contamination. Copyright © 2008 Society of Chemical Industry     

液质联用测定氟尼辛葡甲胺的条件优化

建立了液相色谱-四级杆串联质谱法测定氟尼辛葡甲胺含量的方法,对其检验条件进行了优化。采用Agilent eclipse plus C18色谱柱分离,用体积浓度0.1%甲酸溶液、0.1%甲酸乙腈溶液作为流动相梯度洗脱,电喷雾正离子(ESI+)模式电离,多反应监测(MRM)模式检测,外标法定量。该方法操作灵敏度高,重复性好。     

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.     

黑曲霉降解黄曲霉毒素B1的研究及转录组分析

为探究黑曲霉FS10对AFB_1的降解机制,使用黑曲霉FS10的不同组分(菌悬液、发酵液、孢子、菌丝体)对AFB_1进行降解,并研究了AFB_1刺激对黑曲霉FS10降解效果的影响;利用扫描电子显微镜观察降解过程中黑曲霉菌丝体的形态变化;用转录组学技术探究AFB_1可能的降解机理。结果表明:黑曲霉FS10能有效降解AFB_1,72 h时菌悬液的对AFB_1脱除率高达98.65%;黑曲霉FS10孢子对AFB_1无明显脱除作用,但菌丝体对AFB_1有一定的吸附能力,发酵液对AFB_1有明显脱除效果;经过AFB_1诱导刺激后黑曲霉FS10降解效果有明显提升,表明AFB_1处理能显著提升黑曲霉FS10对AFB_1的降解能力。微观结构分析表明AFB_1处理在一定程度上影响黑曲霉FS10的形态,但随着时间的延长这种影响逐渐减小。此外,转录组学分析表明AFB_1处理降低了一些能量代谢基因的水平,这可能是黑曲霉FS10的一种自我保护机制,同时蛋氨酸的合成基因上调,推测AFB_1的降解可能与蛋氨酸的合成有关。     

贵州秋季栽培不同荞麦品种成熟期果实中黄曲霉及其毒素的分离与鉴定

本研究以贵阳秋季栽培的2个米苦荞(F.tataricum,贵米苦荞18-1号和贵黑米苦荞12号)、2个多苦荞(F.tatari-cymosum,贵多苦荞003C和贵多苦荞60)、2个甜荞(F.esculentum,贵红花甜荞2号和1412-1)、2个常规苦荞(F.tataricum,定苦荞1号和六苦2017)为材料。对其成熟期种子果壳和籽粒进行了黄曲霉分离鉴定,并采用高效液相色谱法对所有品种果壳和籽粒中分离出的黄曲霉菌株进行AFB₁、AFB₂、AFG₁和AFG₂毒素的检测。结果表明,所有品种果壳中均没有分离出黄曲霉菌落;4类荞麦籽粒中仅米苦荞分离出了黄曲霉菌落,共分离出4株黄曲霉菌株。其中贵米苦荞18-1号黄曲霉带菌率为1.56%,贵黑米苦荞12号黄曲霉带菌率为0.78%。分离菌株形态学和ITS序列扩增产物测序结果与已知黄曲霉菌序列完全一致。毒素检测结果表明不同品种之间产毒素差异显著,所有品种籽粒中只有米苦荞中检出4种毒素,贵米苦荞18-1号产AFB₁最高为(5.861±0.055) μg/kg、AFB₂最少为(1.605±0.052) μg/kg,贵黑米苦荞12号产AFB₁最高为(14.475±0.533) μg/kg、AFG₂最少为(3.393±0.151) μg/kg;籽粒产毒量远大于分离菌株产毒量;各分离出菌株之间产毒素能力差异显著,最大产AFT为(11.102±0.095) μg/kg、最小产AFT为(1.794±0.024) μg/kg。上述结果显示供试米苦荞籽粒带菌来源可能是由于果壳开裂籽粒外露后部分籽粒被直接侵染所致。所得结果可为米苦荞中黄曲霉抗性育种研究及荞麦种子的保存、运输、储藏等研究奠定基础。     

液相色谱串联质谱法测定纸制品中PFOS

采用ASE-300快速溶剂取革仪提取样品中全氟辛烷磺酰基化合物(PFOS),经浓缩、净化、过膜、定容后,用液相色谱串连质谱法测定,外标法定量.采用选择离子检测进行阳性确证,提出了纸制品中PFOs的检测方法.本方法的最低检出限、线性范围和方法回收率分别为:0.10mg/kg、0.10～10.0mg/kg和71.0%～103.0%.     

酶联免疫法测定苦荞制品中的黄曲霉毒素B1

用酶联免疫法（ELISA）测定不同苦荞制品中的黄曲霉毒素B1,对如何防控苦荞制品中的黄曲霉毒素B1进行探讨。在分析的4类产品中,苦荞营养粉的黄曲霉毒素B1含量最低,其次是苦荞速溶片和苦荞醋,苦荞米茶中最高。方法的检测灵敏度为0.1 μg/kg,平均回收率在84.70~84.95%,相对标准偏差小于5%。结果表明,酶联免疫法测定准确,稳定性和重现性好,可广泛应用于苦荞及其制品中黄曲霉毒素B1的检测。     

Investigation of food products containing garlic or onion for a false positive sulphite response by LC-MS/MS

ABSTRACT

In the US, sulphites must be declared on the label if they are present in concentrations greater than 10 mg/kg (determined as) SO₂ because an allergic-like response has been reported in a small subset of the population upon consumption of sulphite-containing products. The most widely used method for sulphite determination, the optimised Monier-Williams (OMW), produces false positive results with vegetables from the Allium (garlic) and Brassica (cabbage) genera due to extraction conditions that are thought to cause endogenous sulphur compounds to release SO₂. Recently, an LC-MS/MS method was developed for sulphites but has only been tested with samples that are 100% Allium or Brassica. Since regulatory samples may contain these vegetables as ingredients, additional investigations were necessary to determine the potential extent of false positives. Four blank matrices, chips, phyllo shells, hummus, and quinoa were spiked with various concentrations of onion and garlic powders. The sulphite concentrations were determined using an LC-MS/MS method. The matrix is extracted with a buffered formaldehyde solution, converting free and reversibly bound sulphite to the stable formaldehyde adduct, hydroxymethylsulfonate (HMS). It was determined that even at concentrations up to 8% garlic powder or 2% onion powder, the measured sulphite concentration was below the 10 mg/kg SO₂ labelling threshold. Commercial dried garlic powders were evaluated to determine the variation in responses that might be encountered in future regulatory samples. Recovery studies were conducted to determine if these methods would detect added sulphite. The ability to eliminate false positives due to these ingredients will result in a greater reliability in the accurate determination of added sulphite to ensure compliance with labelling requirements.     

液相色谱-串联质谱法测定豆类中左旋多巴

文章建立一种豆类中左旋多巴的液相色谱-串联质谱测定方法。样品经0.3 mol/L乙酸水溶液超声提取,Agilent Proshell 120 SB-C18(2.1 mm×150 mm,2.7μm)色谱柱分离,以0.1%甲酸水-甲醇为流动相进行梯度洗脱,多反应监测(MRM),内标法定量。结果表明,左旋多巴在0.1~5.0 mg/L范围内线性关系良好,相关系数为0.9994,检出限为1.5 mg/kg,定量限为5.2 mg/kg,方法的平均加标回收率为96.9%~105.5%,日内精密度和日间精密度均小于4%,具有操作简单、灵敏度高、准确度高、重现性好等特点,能够很好满足豆类中左旋多巴含量的检测需要。     

挤压膨化降解糙米中黄曲霉毒素B1

目的：研究挤压工艺参数对黄曲霉毒素B1（aflatoxin B1,AFB1）降解率的影响,为建立粮食产品中AFB1的挤压降解技术提供依据。方法：采用双螺杆挤压机挤压膨化污染AFB1的糙米,分析挤压温度、物料水分、喂料速率和螺杆转速对糙米中AFB1降解率的影响,并通过优化工艺得到最佳工艺条件。结果：单因素试验机筒温度170 ℃时,AFB1降解率最高为37.1%;物料水分24%时,AFB1降解率最高为37.2%;喂料速率30 g/min时,AFB1降解率最高为37.8%;螺杆转速200 r/min时,AFB1降解率最高为39.2%;挤压降解糙米中AFB1正交试验的最佳工艺条件为机筒温度180 ℃、物料水分24%、喂料速率30 g/min、螺杆转速160 r/min,其降解率为48.6%。挤压过程中机筒温度极显著影响AFB1降解,物料水分显著影响AFB1降解,喂料速率和螺杆转速对AFB1降解的影响不显著。结论：挤压膨化加工能有效降解糙米中的AFB1。     

油脂中黄曲霉毒素污染及吸附脱除的研究进展

黄曲霉毒素是在湿热条件下主要由黄曲霉(Aspergillus flavus)和寄生曲霉(Aspergillus parasiticus)产生的一组杂环芳烃类次生代谢产物,具有突出的三致效应,严重危害生态环境和人体健康,因此,黄曲霉毒素的控制已成为国内外科研人员关注的研究热点之一。在食用油的净化技术中,吸附法因其操作简单、效率高、成本低等优点,被认为是控制食用油中微量黄曲霉毒素的主要技术。本文对油脂中黄曲霉毒素污染影响因素和吸附脱除法进行了较为详细的概述,对π-π相互作用、π-络合、酸碱作用和疏水相互作用等吸附机理进行了简单阐述,重点综述了各种吸附剂在该领域的研究进展和未来发展趋势,为开发出更高效的吸附剂用来消减油脂中的黄曲霉毒素提供了研究思路。