Review of the current methods of analytical traceability allowing determination of the origin of foodstuffs

Modern analytical techniques, in particular molecular biology techniques, can determine the plant or animal species present in a foodstuff. It is actually very difficult to determine the geographical origin of a food. The new European regulation 178/2002, applicable on January 1st, 2005 imposes this requirement for the traceability of food. This article gives a progress report on the physicochemical and microbiological analytical techniques available which make it possible to determine the origin of a food with some precision.     

Occurrence of four mycotoxins in cereal and oil products in Yangtze Delta region of China and their food safety risks

A total of 76 cereal and oil products collected from Yangtze Delta region of China were analyzed for occurrences of aflatoxins (AFs), aflatoxin B₁ (AFB₁), ochratoxin A (OTA), deoxynivalenol (DON) and zearalenone (ZEN). The mycotoxins were determined by the standard detection procedures using immunoaffinity column clean-up coupled with fluorometer (or HPLC-UV). ZEN was the most prevalent toxin, with the incidence of 27.6% (range = 10.0–440.0 μg kg⁻¹), and 9.2% of the evaluated samples were contaminated with a concentration higher than that of the legislation limit of China (60 μg kg⁻¹). AFs and AFB₁ were detected in 14.5% of the samples analyzed, the concentrations ranging 1.1–35.0 μg kg⁻¹ for AFs, and 1.0–32.2 μg kg⁻¹ for AFB₁; 4.0% of the samples had the concentrations of AFs and AFB₁ higher than that of the corresponding legislation limits of China (5.0, 10.0 and 20.0 μg kg⁻¹ for different products). OTA was detected in 14.5% of the cereal and oil products collected; the concentrations ranged 0.51–16.2 μg kg⁻¹. Only 2 samples showed OTA levels higher than that of the legislation limit of China (5.0 μg kg⁻¹). DON was detected in 7.9% of the samples; the concentrations ranged 100–700 μg kg⁻¹, and none of the samples showed DON concentration higher than that of the legislation limit of China (1.0 mg kg⁻¹). A total of 15.8% cereal and oil products were contaminated with at least two mycotoxins (multiple contaminations with different combinations including AFs-ZEN, AFs-OTA-ZEN, OTA-ZEN, ZEN-DON, OTA-ZEN-DON). The dietary exposure assessment results indicated that AFs (AFB₁), OTA, DON and ZEN from cereal-based products represented a series health risk to both adults and children in Yangtze Delta region of China. This is the first report of safety evaluation associated with major mycotoxins for the area.     

麦卢卡蜂蜜特征标志物及其分析方法研究进展

麦卢卡蜂蜜是产自新西兰的医疗级蜂蜜,具有独特的非过氧化抗菌活性,抗菌活性与其特征标志物有密切联系。随着国外学者对麦卢卡蜂蜜中抗菌活性物质的深入研究,其中的抗菌活性物质被不断地发现和证实,目前已发现的麦卢卡蜂蜜的特征标志物包括甲基乙二醛、3,5-二甲氧基苯甲酸甲酯-4-双葡萄糖苷、3-苯基乳酸、2-甲氧基苯乙酮、2-甲氧基苯甲酸、4-羟苯基乳酸、Lepteridine等,这些化合物也已应用于麦卢卡蜂蜜的质量评价和真伪鉴别中。麦卢卡蜂蜜在我国进口蜂蜜中所占的比重越来越大,但国内对麦卢卡蜂蜜的研究起步较晚,本文针对与麦卢卡蜂蜜质量评价及真伪鉴别相关的特征标志物及其分析方法进行了综述,以期为麦卢卡蜂蜜的质量评价和真伪鉴别研究提供参考。     

用典型植物监测环境中有机氟污染物的可行性

为探究用典型植物指示环境中全氟化合物(perfluorinated chemicals,PFCs)污染状况的可行性,采用高效液相色谱-质谱联用(high performance liquid chromatography-tandem mass spectrometry,HPLCMS/MS),分析苔藓、樟树、马尾松、唐菖蒲、地衣、苜蓿、银桦和杜鹃8种植物鲜叶中13种PFCs的残留水平,从中选择富集PFCs能力最强的苔藓为环境生物指示物.结合循环中子活化分析测定深圳市宝安、南山、福田、罗湖、盐田和龙岗6区12个位点苔藓中总氟(total fluorine,TF)、可萃取有机氟(extractable organic fluorine,EOF)和PFCs的含量.结果显示,苔藓中EOF占TF的13.4％ ～ 16.5％,表明无机氟为主要存在形态;可鉴别氟(以氟计量的总PFCs)仅占EOF的0.08％ ～0.15％,显示99.8％以上的EOF仍有待鉴别;全氟辛烷磺酸、全氟己酸、全氟辛酸之和占总PFCs的88％ ～ 99％,为苔藓中PFCs主要残留种态;深圳市宝安区苔藓中PFCs残留总量显著高于其他5区(P＜0.01),原因与区内PFCs相关产业密集及其地理气候条件密切相关.利用苔藓指示环境中PFCs污染及其暴露风险是可行的.     

An ultra-sensitive monoclonal antibody-based fluorescent microsphere immunochromatographic test strip assay for detecting aflatoxin M1 in milk

A rapid lateral flow fluorescent microsphere immunochromatographic test strip (FM-ICTS) assay has been developed for the detection of aflatoxin M₁ (AFM₁) residues in milk. For this purpose, an ultra-sensitive anti-AFM₁ monoclonal antibody (MAb) 1D3 was prepared and identified. The IC₅₀ value of the MAb 1D3 for AFM₁ was 23 ng/L, and the cross-reactivity (CR) of the MAb with aflatoxin M₂, aflatoxin B₁, aflatoxin B₂, aflatoxin G₁ and aflatoxin G₂ was 18%, 9%, <0.15%, 43% and <0.3%, respectively. The MAb was covalently conjugated with carboxylate-modified FMs, and the FMs were used as the label in a competitive immunochromatography assay. Using a moderate hapten-to-protein coupling ratio (˜2) in the coating antigen resulted in improved immunoassay sensitivity. Under optimal conditions, the IC₅₀ value of the assay was 36.3 ng/L with the limit of detection (LOD) of 4.4 ng/L in milk samples using a fluorescence reader, and the recoveries of AFM₁ in spiked milk samples ranged from 76.6 to 110.8% with coefficient of variation (CV) of 4–14.7%. The whole procedure could be completed within 30 min. The results demonstrated that the FM-ICTS assay is easy to conduct, rapid, highly sensitive and specific for the detection of AFM₁ residues in milk.     

副溶血性弧菌快速定量检测方法研究进展

副溶血性弧菌（VP）是我国沿海地区食物中毒最常见的病原菌之一,引发的食品安全事件逐年上升。目前定量检测食品中副溶血性弧菌的国家标准方法为最大可能数法,该方法检测时限长且操作步骤繁琐,不能满足快速定量检测的需求。随着现代生物技术的发展,新的定量检测方法不断涌现,研发了多种快速灵敏的副溶血性弧菌定量检测方法。本文综述了近年来生物技术领域常见的定量方法在副溶血性弧菌快速定量检测中的研究现状及应用进展,充分了解各检测方法的特点,以期为食品中副溶血性弧菌的快速精准定量检测研究提供理论参考及发展方向。     

正丁醇常数法快速测定煎炸油脂中羰基价

目的利用正丁醇常数法快速测定煎炸油脂中羰基价。方法 采用正丁醇为提取溶剂对煎炸油脂进行羰基价测定,用比色法测得吸光度值,通过吸光度常数直接算出羰基价。结果正丁醇常数法比现有国标方法更安全、简便,方法添加回收率为88%~127%,相对标准偏差为1.92%~9.82%。结论 该法快速、简便、精密度和准确度高,适用于煎炸油脂中羰基价的测定。     

不同产地三文鱼的稳定同位素指纹特征及原产地溯源

本研究从深圳口岸获取我国三文鱼主要进口国（法罗群岛、挪威、智利、加拿大以及澳大利亚）的三文鱼样品共16?份,并采集中国产三文鱼（虹鳟）样品2?份,分析三文鱼肌肉、表皮、鳞片以及骨骼中的碳、氮、氢、氧、硫稳定同位素比值,比较不同产地以及不同部位同位素分布差异,采用判别分析对不同产地进行判别。三文鱼的碳、硫以及氢、氧稳定同位素具有显著的产地差异。不同组织之间同位素呈现明显的同位素分馏效应。鳞片以及表皮同位素比值对产地的指示效果优于肌肉和骨骼,结果表明采用稳定同位素能完全将以上产地的样品区分开,且还能将中国的虹鳟与进口的三文鱼进行区分。对市场随机购买的6?份三文鱼样品的产地鉴别结果表明,稳定同位素技术能有效鉴别市场中三文鱼的产地造假行为,可用于对市场上三文鱼的产地追溯,以期为我国食品安全提供技术保障。     

α-葡萄糖苷酶试验在克罗诺杆菌鉴定中的应用

目的研究α-葡萄糖苷酶试验在克罗诺杆菌的快速准确鉴定中的应用。方法对包括克罗诺杆菌在内的56株肠杆菌科细菌进行纯培养后,将单个菌落的生理盐水混悬液,加到α-葡萄糖苷酶检测试剂中,于37℃水浴培养4 h后,在405 nm波长处测量其吸光度值,进行α-葡萄糖苷酶试验。同时将56株菌接种于TSA琼脂平板,于25℃培养48h后,在自然光下观察菌落的黄色素。结果 40株克罗诺杆菌的α-葡萄糖苷酶试验均为阳性;包括阴沟肠杆菌、大肠埃希氏菌、产气肠杆菌在内16株肠杆菌,α-葡萄糖苷酶试验均为阴性。在40株克罗诺杆菌中,有37株菌产黄色素试验为阳性, 3株菌产黄色素试验为可疑;其他16株肠杆菌,产黄色素试验均为阴性。结论与产黄色素试验相比,用α-葡萄糖苷酶试验鉴定克罗诺杆菌,结果更准确,且检测时间短、客观性强。     

口服液中全氟烷基类化合物的快速测定

建立了高效液相色谱-串联质谱法（HPLC-MS/MS）检测口服液中16种全氟烷基类化合物（PFASs）。样品采用2%盐酸酸化甲醇溶液提取,用NaOH溶液将提取液的pH值调至中性后,加入PSA和GCB粉末吸附剂分散固相萃取富集净化,用50 mmol/L三乙胺-甲醇溶液洗脱,HPLC-MS/MS负离子多反应监测模式测定,同位素内标法定量。结果表明：在0.2~20 μg/L浓度范围内,16种全氟烷基类化合物具有良好的线性关系,线性相关系数（r）大于0.996,方法的检出限均小于0.15 μg/L,定量限均小于0.43 μg/L;在0.5、1.0、2.0和5.0 μg/L添加水平下,化合物的平均回收率在80.8%~119%之间,相对标准偏差均小于10.5%。应用该方法对市场上随机采购的24种口服液样品进行检测,检出了14种PFASs化合物,其中以PFBA、PFOA、PFHxA、PFHpA、PFNA、PFDA最为普遍,最高浓度达5.05 μg/kg。该方法快速、简便、灵敏度高、重现性好,适用于口服液中PFASs的检测。