支气管内给予黄曲霉毒素G_1对大鼠肺组织的作用

目的探讨一次性支气管内给予黄曲霉毒素G1(AFG1)对大鼠肺组织的影响。方法经支气管一次性给予30μg.kg-1AFG1处理雄性SD大鼠。AFG1处理1,3,7和14 d后,分别处死实验动物,以扫描电镜方法观察大鼠肺组织超微结构变化,采用原位杂交方法检测肺组织肿瘤坏死因子-α(TNFα-)mRNA表达情况,测定H2O2的降低量代表抗氧化能力。结果溶剂对照组肺组织超微结构、TNFα-mRNA表达和抗氧化能力和对照组比较未见明显改变。AFG1处理后,扫描电镜观察可见肺泡壁增厚且粗细不均,肺泡腔表面细胞有隆起,细胞肿胀,Ⅱ型肺泡上皮细胞表面微绒毛变短、消失,病变以AFG1处理后7和14 d为明显。原位杂交法结果表明,AFG1处理后1,3,7和14 d组肺组织肺泡细胞TNF-αmRNA表达的阳性细胞数分别为(22.1±4.0)%,(20.3±4.2)%,(32.3±4.2)%和(24.7±3.8)%,明显高于溶剂对照1 d组(1.2±0.3)%(n=5,P<0.01)。AFG1处理后除d 1外,d 3,7和14肺组织抗氧化能力分别为(53.4±12.4),(42.7±10.8)和(47.2±11.0)mo.lm in-1.g-1蛋白,明显低于溶剂对照1 d组(61.9±4.3)mo.lm in-1.g-1蛋白(n=5,P<0.05)。结论AFG1对大鼠肺组织有一定的损伤作用,降低肺组织抗氧化能力,上调肺泡细胞TNFα-mRNA的表达。     

远志黄曲霉毒素检测及其贮藏过程中黄曲霉菌变化研究

目的 研究不同产地远志中黄曲霉毒素B₁、B₂、G₁、G₂（AFB₁、AFB₂、AFG₁、AFG₂）的污染情况及贮藏过程中黄曲霉菌的变化。方法 收集12批不同产地的远志药材,采用性状、显微及DNA分子鉴定方法对其表面的黄曲霉菌进行鉴定;利用超高效液相色谱-三重四级杆串联质谱法（UPLC-MS/MS）测定其黄曲霉毒素含量;通过稀释平板法观察远志在北京贮藏6个月以来其表面黄曲霉菌的变化情况。结果 12批远志药材表面均分离鉴定出了黄曲霉菌,且全部检出黄曲霉毒素,其中33.3%的样品超过《中华人民共和国药典》2020年版中远志项下黄曲霉毒素B₁、黄曲霉毒素总量的限定标准。结合北京的气候条件分析,在温度、湿度较高的夏季,远志表面的黄曲霉菌数量最多,在温、湿度较低的秋冬季节,远志表面的黄曲霉菌数量较低。结论 远志表面黄曲霉毒素污染问题十分严重,贮藏条件的温度、湿度变化对远志表面的黄曲霉菌数量有很大影响,可作为优化远志贮藏条件的参考依据。     

淡豆豉炮制中黄曲霉毒素产毒株的筛选鉴定和产毒能力测定

目的 对淡豆豉炮制过程中产黄曲霉毒素(aflatoxins,AFTs)的微生物(简称产毒菌)进行筛选鉴定、定量分析和产毒能力测定.方法 运用紫外荧光法初筛淡豆豉炮制中各样本的产毒菌并菌落计数;对初筛菌株的18S rDNA序列进行PCR扩增、测序,测序结果经NCBI同源性比对、MEGA7.0软件构建系统发育树进行分子生物...     

Mycotoxins in Pistachios (Pistacia vera L.): Methods for Determination,Occurrence, Decontamination

The consumption of pistachios (Pistacia vera L.) has been increasing, given their important benefit to human health. In addition to being an excellent nutritional source, they have been associated with chemical hazards, such as mycotoxins, resulting in fungal contamination and its secondary metabolism. Aflatoxins (AFs) are the most common mycotoxins in pistachio and the most toxic to humans, with hepatotoxic effects. More mycotoxins such as ochratoxin A (OTA), fumonisins (FBs), zearalenone (ZEA) and trichothecenes (T2, HT2 and DON) and emerging mycotoxins have been involved in nuts. Because of the low levels of concentration and the complexity of the matrix, the determination techniques must be very sensitive. The present paper carries out an extensive review of the state of the art of the determination of mycotoxins in pistachios, concerning the trends in analytical methodologies for their determination and the levels detected as a result of its contamination. Screening methods based on immunoassays are useful due to their simplicity and rapid response. Liquid chromatography (LC) is the gold standard with new improvements to enhance accuracy, precision and sensitivity and a lower detection limit. The reduction of Aspergillus’ and aflatoxins’ contamination is important to minimize the public health risks. While prevention, mostly in pre-harvest, is the most effective and preferable measure to avoid mycotoxin contamination, there is an increased number of decontamination processes which will also be addressed in this review.     

Hollow-Structured Microporous Organic Networks Adsorbents Enabled Specific and Sensitive Identification and Determination of Aflatoxins

Aflatoxin (AFT) contamination, commonly in foods and grains with extremely low content while high toxicity, has caused serious economic and health problems worldwide. Now researchers are making an effort to develop nanomaterials with remarkable adsorption capacity for the identification, determination and regulation of AFT. Herein, we constructed a novel hollow-structured microporous organic networks (HMONs) material. On the basis of Fe₃O₄@MOF@MON, hydrofluoric acid (HF) was introduced to remove the transferable metal organic framework (MOF) to give hollow MON structures. Compared to the original Fe₃O₄@MOF@MON, HMON showed improved surface area and typical hollow cavities, thus increasing the adsorption capacity. More importantly, AFT is a hydrophobic substance, and our constructed HMON had a higher water contact angle, greatly enhancing the adsorption affinity. From that, the solid phase extraction (SPE-HPLC) method developed based on HMONs was applied to analyze four kinds of actual samples, with satisfied recoveries of 85–98%. This work provided a specific and sensitive method for the identification and determination of AFT in the food matrix and demonstrated the great potential of HMONs in the field of the identification and control of mycotoxins.     

Mycotoxins Exposure in Cabinda,Angola—A Pilot Biomonitoring Survey of Breastmilk

Breast milk is considered the ideal form of nutrition for newborns and infants. However, it can carry over contaminants, namely mycotoxins, with biological effects to which this population is particularly vulnerable. Human biomonitoring and surveillance programs are particularly scarce in low-income countries, where food security is a more urgent priority in comparison with food safety. This pilot survey aims to assess exposure of breastfed infants to aflatoxin M1 (AFM1), zearalenone (ZEN), and ochratoxin A (OTA) in Angola, and to evaluate the main socio-demographical and food consumption determinants of lactating mothers. All 37 breast milk samples analyzed are found to be contaminated with ZEN and OTA, although none are found contaminated with AFM1. Contamination levels are lower than previously reported for ZEN but higher in the case of OTA. A significant association between ZEN levels in breast milk and the consumption of cookies by the lactating mothers is found. As for OTA, higher levels are observed in the milk from mothers with younger infants, for which high estimated daily intake (EDI) is determined. As far as the authors are aware, this is the first survey of the occurrence of mycotoxins in breast milk in Angola, so further human biomonitoring works should follow, given that mycotoxins are a global health issue that directly impact the health of populations.     

Cumulative Effects of Non-Aflatoxigenic Aspergillus flavus Volatile Organic Compounds to Abate Toxin Production by Mycotoxigenic Aspergilli

Previously, authors reported that individual volatile organic compounds (VOCs) emitted by non-aflatoxigenic Aspergillus flavus could act as a mechanism of biocontrol to significantly reduce aflatoxins and cyclopiazonic acid (CPA) produced by toxigenic strains. In this study, various combinations and volumes of three mycotoxin-reductive VOCs (2,3-dihydrofuran, 3-octanone and decane) were assessed for their cumulative impacts on four Aspergillus strains (LA1–LA4), which were then analyzed for changes in growth, as well as the production of mycotoxins, including aflatoxins, CPA and multiple indole diterpenes. Fungal growth remained minimally inhibited when exposed to various combinations of VOCs. No single combination was able to consistently, or completely, inhibit aflatoxin or CPA across all toxigenic strains tested. However, the combination of 2,3-dihydrofuran and 3-octanone offered the greatest overall reductions in aflatoxin and CPA production. Despite no elimination of their production, findings showed that combining VOCs produced solely by non-aflatoxigenic A. flavus still inhibited several agriculturally important mycotoxins, including B and G aflatoxins and CPA. Therefore, other VOC combinations are worth testing as post-harvest biocontrol treatments to ensure the prolonged effectiveness of pre-harvest biocontrol efforts.     

Aspergillus flavus and Total Aflatoxins Occurrence in Dairy Feed and Aflatoxin M1 in Bovine Milk in Aguascalientes,Mexico

Contamination of food chains by toxigenic fungi and aflatoxins is a global problem that causes damage to human health, as well as to crop and livestock production. The objective is to evaluate Aspergillus flavus and total aflatoxins (AFs) occurrence in totally mixed rations (TMRs) for dairy cows and aflatoxin M₁ (AFM₁) in milk for human consumption. Ninety-nine dairy production units located in Aguascalientes, Mexico, were randomly selected, and samples were collected from TMRs, raw milk, and milk marketed in the city in two consecutive agricultural cycles. AFs were quantified in TMRs and milk by indirect enzyme immunoassay and HPLC; aflatoxigenic and molecular (PCR) capacity of monosporic A. flavus isolates in the feed was characterized. All feed, raw, and pasteurized milk samples showed aflatoxin contamination (26.0 ± 0.4 µg/kg, 32.0 ± 1.0, and 31.3 ± 0.7 ng/L, respectively), and a significant proportion (90.4, 11.3, and 10.3%) exceeded the locally applied maximum permissible limits for feed and milk (20.0 µg/kg and 50 ng/L). Aflatoxin contamination in both TMRs and milk indicated a seasonal influence, with a higher concentration in the autumn–winter cycle when conditions of higher humidity prevail. The results obtained suggest the existence of contamination by aflatoxigenic A. flavus and aflatoxins in the diet formulated for feeding dairy cows and, consequently, in the dairy food chain of this region of the Mexican Highland Plateau.     

HPLC法测定虫草发酵粉中黄曲霉毒素残留量

目的:建立虫草发酵粉中黄曲霉毒素B1、B2、G1、G2的残留量测定方法。方法:样品经有机溶剂提取、免疫亲和柱净化后,利用高效液相色谱-光化学衍生-荧光检测器进行分析测定。结果:黄曲霉毒素G2、B2在1.5～150 pg范围内线性关系良好,黄曲霉毒素G1、B1在5～500 pg范围内线性关系良好,r>0.9998。回收率在80%～93%之间。结论:该方法快速简便,准确,可作为虫草发酵粉黄曲霉毒素的残留量测定方法,亦可作为原料药的黄曲霉毒素筛查方法,以达到控制产品质量的目的。     

Development of PCR,LAMP and qPCR Assays for the Detection of Aflatoxigenic Strains of Aspergillus flavus and A. parasiticus in Hazelnut

Aspergillus flavus and A. parasiticus are two species able to produce aflatoxins in foodstuffs, and in particular in hazelnuts, at harvest and during postharvest phase. As not all the strains of these species are aflatoxin producers, it is necessary to develop techniques that can detect aflatoxigenic from not aflatoxigenic strains. Two assays, a LAMP (loop-mediated isothermal amplification) and a real time PCR with TaqMan^® probe were designed and validated in terms of specificity, sensitivity, reproducibility, and repeatability. The capability of the strains to produce aflatoxins was measured in vitro and both assays showed to be specific for the aflatoxigenic strains of A. flavus and A. parasiticus. The limit of detection of the LAMP assay was 100–999 picograms of DNA, while the qPCR detected 160 femtograms of DNA in hazelnuts. Both techniques were validated using artificially inoculated hazelnuts and naturally infected hazelnuts. The qPCR was able to detect as few as eight cells of aflatoxigenic Aspergillus in naturally infected hazelnut. The combination of the LAMP assay, which can be performed in less than an hour, as screening method, with the high sensitivity of the qPCR, as confirmation assay, is able to detect aflatoxigenic strains already in field, helping to preserve the food safety of hazelnuts.