免疫亲和柱净化—液相色谱法测定玉米油中的玉米赤霉烯酮含量

目的 建立免疫亲和柱净化—液相色谱法测定玉米油中玉米赤霉烯酮含量的分析方法。方法 样品采用乙腈-水(9:1, V:V)提取, 免疫亲和柱净化, 经Inertsil ODS3-C18柱 (250 mm×4.6 mm, 5 μm)分离, 以乙腈-水-甲醇(46:46:8, V:V:V)为流动相进行等度洗脱, 流速1.5 mL/min, 柱温30 ℃, 经荧光检测器检测, 外标法定量。结果 玉米赤霉烯酮在25~2500 μg/kg范围内具有良好线性, 相关系数为0.99998, 检出限5 μg/kg, 加标回收率为87.5%~107.5%, 相对标准偏差为3.2%~5.8%。对调和油中米赤霉烯酮质控考核样品Mycotoxin-PT-2018-042的检测结果满意。结论 该方法前处理操作简便, 损失少, 减少了试剂用量, 灵敏度高, 准确度高, 适用于玉米油中玉米赤霉烯酮的检测。     

胶体金免疫层析法快速测定玉米和小麦中玉米赤霉烯酮

采用高效液相色谱法对玉米赤霉烯酮阳性样品进行定值,将阳性样品制备为不同毒素含量的验证样品,对胶体金免疫层析法的准确性、重复性、稳定性、最低检出限、误差范围进行了验证试验,并且完成了对实际样品的检测,同时采用酶联免疫法（ELISA）进行对比,试验结果为：最低检出限为60μg/kg,其检测结果与酶联免疫法基本一致,方法具有...     

Enniatins fromFusarium avenaceum isolated from balsam fir foliage and their toxicity to spruce budworm larvae,Choristoneura fumiferana (Clem.) (Lepidoptera: Tortricidae)

Material extracted from hyphae ofFusarium avenaceum, isolated from foliage of balsam fir,Abies balsamea, was toxic to spruce budworm larvae when incorporated into insect diet. The major insecticidal component of the toxic fraction was identified by chemical and spectroscopic methods as enniatin complex, rich in enniatin A/A₁. Possible ecological implications of these observations are considered.     

Occurrence and levels of mycotoxins and their metabolites in human breast milk associated to dietary habits and other factors: A systematic literature review, 1984–2015

BackgroundMany studies around the world reported the occurrence of many mycotoxins and their metabolites in human breast milk. However the contamination by aflatoxin M1 and ochratoxin A were the most investigated by several countries.Scope and approachTo scrutinize all papers reporting quantitative data on the prevalence and the levels of mycotoxins and their metabolites in breast milk, also the circumstances of exposure.A systematic literature search in Pubmed, Science direct and Google scholar databases were performed to identify relevant studies, published in English from 1984 through May 2015.Key findings and conclusion63 studies met the inclusion criteria and assessed the occurrence of 29 mycotoxins & their metabolites in breast milk, regarding 7194 subjects of 31 countries. The maternal dietary habits, the socio demographic status of the mother, the seasonal variations and the sensitivity of the analytical method were the factors related to the high concentrations of AFM1 and OTA in breast milk.Studies where contamination exceeds maximum limits and exhibit real risk of public health were highlighted.     

玉米赤霉烯酮降解菌的筛选与鉴定

采用富集驯化的方法从猪粪便中分离出一株能够高效降解玉米赤霉烯酮(zearalenone, ZEN)的菌株,命名为ZJ-2019-1。通过16S rDNA序列分析方法对其进行了鉴定,研究了反应时间、培养基初始pH、温度、毒素浓度等因素对ZJ-2019-1降解ZEN的影响,同时对该菌株清除ZEN的机理进行了初步探索。结果表明:ZJ-2019-1为枯草芽孢杆菌(Bacillus subtilis);该菌株在48 h内能将LB培养基中初始浓度为10 mg/L的ZEN去除99.7%;该菌株降解ZEN的最适温度为37℃,当反应温度低于27℃时,该菌株对ZEN的清除率明显降低;当培养基初始pH 5.0～9.0时,ZJ-2019-1对ZEN的清除率能达到88%以上,其中初始pH 7.0为降解反应的最适pH;当初始ZEN浓度在20 mg/L以内时,ZJ-2019-1对ZEN的清除率都在95%以上;ZJ-2019-1对ZEN的清除作用主要源于胞外酶的活性。     

外送餐引起产气荚膜梭菌食物中毒流行病学调查分析

目的查明发生在某工厂的食源性疾病暴发的可疑食品、致病因子及危险因素等,并对事件调查过程中暴露出的问题进行探讨,为今后类似事件的防控和调查提供参考依据。方法病例定义为于2019年3月3日～3月4日期间在M工厂加班职工中发生腹痛、腹泻(≥3次/24 h)或呕吐症状之一者,运用描述性和分析性流行病学方法开展病例访谈和回顾性研究。收集病例的粪便标本、剩余食品和相关环境样品进行病原分离和采用聚合酶链式反应(PCR)检测阳性菌株的毒素基因。结果检索到病例106名,罹患率为73.6%(106/144),临床症状以腹泻(78.3%,83/106)、腹痛(78.3%,83/106)为主,部分半腹部胀气、胀痛(9.4%,10/106),无发热;流行曲线为点源暴露模式,潜伏期为2～22 h,可疑餐次为2019年3月3日的午餐;单因素分析和Logistic回归分析结果显示,发病与红烧鱼块[相对危险度(RR)=1.55, 95%置信区间(95%CI):1.29～1.85]、蒜苗肉丝(RR=1.26, 95%CI:1.01～1.57)和雪菜烧鸭血(RR=1.47, 95%CI:1.16～1.87)有关;在3份肛拭子、3份环境样品中检出产气荚膜梭菌,菌株和2份剩余食品均检测出α毒素和产气荚膜梭菌肠毒素(CPE)基因。送餐的D企业在加工经营中存在着被细菌污染并繁殖的条件。结论本次事件是因食用某供餐企业提供的配送餐引起的产气荚膜梭菌食物中毒,外送餐做好后应迅速冷却、低温储存,不能立即进食的,在食前要充分加热。     

Binding of aflatoxin B1 by probiotic bacteria

The ability of six probiotic bacteria to bind a common food carcinogen, aflatoxin B₁, was assessed. The studied strains included Lactobacillus strains and one Bifidobacterium strain. The strains were incubated in vitro with alfatoxin B₁ and the toxin residue in the supernatant was measured using high‐performance liquid chromatography. The aflatoxin‐binding capacity of the strains was found to range from 5.8 to 31.3%. The results further support the observation that a number of probiotic bacteria are able to bind specific dietary contaminants. Although the extent of binding varies depending on the bacterial strain used, the data may explain some of the antimutagenic and anticarcinogenic effects of probiotic micro‐organisms. © 2000 Society of Chemical Industry     

A Genus-Wide Bioactivity Analysis of Daboia (Viperinae: Viperidae) Viper Venoms Reveals Widespread Variation in Haemotoxic Properties

The snake genus Daboia (Viperidae: Viperinae; Oppel, 1811) contains five species: D. deserti, D. mauritanica, and D. palaestinae, found in Afro-Arabia, and the Russell’s vipers D. russelii and D. siamensis, found in Asia. Russell’s vipers are responsible for a major proportion of the medically important snakebites that occur in the regions they inhabit, and their venoms are notorious for their coagulopathic effects. While widely documented, the extent of venom variation within the Russell’s vipers is poorly characterised, as is the venom activity of other species within the genus. In this study we investigated variation in the haemotoxic activity of Daboia using twelve venoms from all five species, including multiple variants of D. russelii, D. siamensis, and D. palaestinae. We tested the venoms on human plasma using thromboelastography, dose-response coagulometry analyses, and calibrated automated thrombography, and on human fibrinogen by thromboelastography and fibrinogen gels. We assessed activation of blood factors X and prothrombin by the venoms using fluorometry. Variation in venom activity was evident in all experiments. The Asian species D. russelii and D. siamensis and the African species D. mauritanica possessed procoagulant venom, while D. deserti and D. palaestinae were net-anticoagulant. Of the Russell’s vipers, the venom of D. siamensis from Myanmar was most toxic and D. russelli of Sri Lanka the least. Activation of both factor X and prothrombin was evident by all venoms, though at differential levels. Fibrinogenolytic activity varied extensively throughout the genus and followed no phylogenetic trends. This venom variability underpins one of the many challenges facing treatment of Daboia snakebite envenoming. Comprehensive analyses of available antivenoms in neutralising these variable venom activities are therefore of utmost importance.     

Aflatoxin B1, ochratoxin A and zearalenone in sorghum grains marketed in Tunisia

A total of 64 samples of sorghum (37 Tunisian sorghum samples and 27 Egyptian sorghum samples) were collected during 2011–2012 from markets in Tunisia. Samples were analysed for contamination with aflatoxin B1, ochratoxin A and zearalenone by High-Performance Liquid Chromatography Coupled with Fluorescence Detection (HPLC-FLD). Aflatoxin B1 was found in 38 samples in the range 0.03–31.7 µg kg^?1. Ochratoxin A was detected in 24 samples with concentrations ranging from 1.04 to 27.8 µg kg^?1. Zearalenone was detected in 21 samples and the concentration varied between 3.7 and 64.5 µg kg^?1. ANOVA analysis of the influence of the country of origin on the incidence and concentration of mycotoxins in the samples studied showed no significant difference (P > 0.05) between the two batches of samples for each of the three mycotoxins studied. The studied mycotoxins contaminate sorghum and may also co-exist because of the diversity of the mycobiota in this cereal.