4-Methylimidazole in soluble coffee and coffee substitutes

Soluble coffee and coffee substitutes' consumption has grown considerably in recent years. These products, prepared from roasted coffee and/or cereal extracts, are more consumer-friendly than plain coffee, being usually cheaper. During roasting, several toxic compounds can be produced from carbohydrate degradation in presence of aminoacids, including 4-methylimidazole (4-MeI). This work aimed to screen the presence of 4-MeI in soluble coffee and its surrogates commercialized in Portugal using a previously validated gas chromatography-mass spectrometry (GC–MS) method. In a total of 45 soluble samples analyzed, including 10 plain coffees, 8 decaffeinated coffees, 12 cereal mixtures with coffee and 15 cereal mixtures without coffee, all the samples were positive for 4-MeI, with levels that ranged from 136 to 1411 μg/kg. All cereal-containing samples had significantly higher amounts (p < 0.01) than coffee samples, whilst no statistical differences were observed between decaffeinated and plain coffees. The high variability observed between samples is not influenced by the “brand” effect as well as by raw-material.     

中性氧化铝柱净化-UPLC-MS/MS法测定乳和乳制品中黄曲霉毒素M_1

建立了中性氧化铝固相萃取柱净化,超高效液相色谱-串联质谱法(UPLC-MS/MS)测定乳和乳制品中黄曲霉毒素M1的分析方法。样品经乙腈提取,乙酸锌辅助沉淀蛋白,中性氧化铝SPE柱净化,以乙腈和0.1%甲酸水溶液作为流动相进行梯度洗脱,以电喷雾离子源(ESI)在正离子多反应监测(MRM)模式下进行测定,外标法定量。结果表明,黄曲霉毒素M1在0.1~50μg/L浓度范围内呈良好的线性关系,相关系数(r2)大于0.99;空白样品加标回收率在70.8%~79.2%之间,相对标准偏差小于8%。方法检出限为0.02μg/kg,定量限为0.05μg/kg。该方法实用、准确、灵敏,适用于乳和乳制品中黄曲霉毒素M1的测定。     

The international risk governance council framework and its application to Listeria monocytogenes in soft cheese made from unpasteurised milk

The International Risk Governance Council (IRGC) developed a Risk Governance Framework whose purpose is to help policy makers, regulators and risk managers both understand the concept of risk governance and apply it to their handling of risks. The Framework allows input from the scientific and public health perspective as well as the less-easily measurable side of freedom of choice. For food, the public wants many choices and less regulation, but at the same time safe products to consume. These ideals are at times in conflict. One example of this is the demand for soft cheese made from unpasteurised milk which may be contaminated with L. monocytogenes or other pathogens. Distinguishing between simple, complex, uncertain and ambiguous risks can help to design a risk management strategy. Public health advocates typically see management of soft cheese made from unpasteurised milk as a simple risk (protection of health), whereas for a small but vociferous proportion of the public sees it more of an uncertain or ambiguous one (choice trumps the slight risk of illness). The implications of five management options for the cheese are discussed. The new Codex Guidelines tend to put these cheeses into Option 1, a strict control on the presence of the pathogen, which will be ignored by the cheese aficionados. Other options are worth exploring to give some more choice but at low risk.     

玉米赤霉烯酮样品前处理与快速检测技术 研究进展

玉米赤霉烯酮是一种毒性极强的小分子,具有弱雌激素活性,其性质相对稳定,缺乏特效解毒剂。其检测方法主要有生物检测法、理化检测法和免疫学检测法,其中免疫检测法因快速、简便、灵敏而得到较为广泛的应用。本文综述了玉米赤霉烯酮的样品前处理技术、免疫学快速检测技术及相关专利的研究进展情况,并对玉米赤霉烯酮的样品前处理技术及其检测产品的开发进行了展望。     

QuEChERS-超高效液相色谱-串联质谱法快速测定豆制品中二甲基黄和碱性嫩黄O的含量

目的建立QuEChERS结合超高效液相色谱-串联质谱法(QuEChERS-ultra performance liquid chromatography-tandem mass spectrometry,QuEChERS-UPLC-MS/MS)快速测定豆制品中二甲基黄和碱性嫩黄O的含量。方法豆制品经20 m L乙腈-水(1:1,V:V)浸泡,采用QuEChERS方法进行萃取、净化,经Shim-pack XR-ODSⅢ色谱柱分离,正离子扫描,多反应监测模式进行质谱分析,外标法定量。结果二甲基黄在添加水平为0.5、1和10μg/kg时,方法回收率为81.6%~97.2%;碱性嫩黄O在添加水平为6、10和50μg/kg时,方法回收率为89.1%~100.7%;二甲基黄和碱性嫩黄O的相对标准偏差均小于12%(n=6);二甲基黄和碱性嫩黄O的检出限分别为0.5、2μg/kg;定量限分别为1.5、6μg/kg。结论该方法操作简便、快速准确,适用于豆制品中二甲基黄、碱性嫩黄O的快速筛查和定量分析。     

基于分子生物学技术检测食物过敏原的研究进展

食物过敏现象越来越普遍,已经严重影响了部分人群的生活质量甚至危及生命,国际上有关食物过敏事件的报道屡见不鲜。如何快速、准确、高通量、低成本地检测食物中的过敏原成分,已成为监管部门和食品企业的关注焦点。本文综述了以酶联免疫吸附法、PCR法、实时荧光定量PCR法、环介导等温扩增技术及生物芯片技术为主的几种分子生物学检测技术检测食物过敏原的方法,并对这几种方法的准确性、重复性等进行比较,探讨了食品中过敏原检测方法的发展前景。与传统过敏原检测方法相比,现行生物芯片技术具有高通量、对单一样品同时检测多种过敏原成分的特点,将成为一种新颖有效的过敏原检测工具。     

数控技术在木工车床上的应用

随着家具、建材等木材需求行业的飞速发展,传统的木工机械已经不能满足要求。数控技术应用于木工机械成为了大势所趋。与传统木工车床相比,数控车床具有自动送料、通用车刀取代特制仿形刀具、数控车刀运行轨迹、图形输入等优点,在提高产品加工精度的同时,克服了传统木工车床手动单条装料、不同规格产品须制作仿行刀具、频繁调试等缺陷,更好地满足市场发展需求。     

正相高效液相色谱法测定鱼肝油中的维生素D3

建立一种正相高效液相色谱法测定鱼肝油中VD3含量的新方法。采用Agilent ZORBAX Rx-SIL色谱柱,以95%正己烷-5%异丙醇为流动相,流速为1.0 mL/min,PDA检测波长264 nm。结果表明:VD3浓度在0.2μg/mL～20μg/mL范围内,峰面积与含量具有良好的线性关系(r=0.999 7);平均相对标准偏差为0.62%,平均回收率为94.2%。该方法可作为鱼肝油中VD3含量的一种快速检测方法。     

月饼中黄曲霉毒素B1检测前处理方法的改进

通过对伍仁、蛋黄莲蓉、枣泥、水果、火腿、冰皮和吞拿鱼七种口味,共70批次月饼进行甲醇-水(1∶1,V/V)和三氯甲烷二次抽提两种处理方法对比,结果显示两种方法检测仅伍仁和吞拿鱼月饼差异显著,其余不显著.甲醇水提取方法检测结果重复性良好,加标回收率为84.0％114.7％,提高了月饼黄曲霉毒素B1的检测效率.