揭开转基因食品的神秘面纱

爱因斯坦曾经说过:“科学技术是一把双刃剑,它可以造福于人类,也可以给人类带来灾难”。自转基因食品(GM FOOD)诞生之日起,就在世界范围内引起极大争议,已经在世界上多个国家成了环境和健康的中心议题。     

Development and in-house validation of a reference molecule pMIR604 for simplex and duplex event-specific identification and quantification of GM maize MIR604

Effective analysis methods for genetically modified organisms (GMOs) using reliable reference molecules as calibrators are necessary for the implementation of labeling policies. While no available detection systems based on the reference molecule have been reported for GM maize MIR604. Here we established the simplex and duplex qualitative and quantitative PCR systems for maize MIR604 employing a reliable new reference molecule pMIR604 as a calibrator, which contains fragments of the revealed 5′ flanking sequence of maize MIR604 and taxon-specific sequence zSSIIb. The limits of detection (LODs) were both 10 copies. The absolute LOD and limit of quantification were confirmed to be as low as 10 and 25 copies of pMIR604 through in-house validation both in simplex and duplex real-time PCR assays. For quantification of practical samples, results from five operators indicated that the biases of the data derived from each participant ranged from 2.00 to 23.00% and from 3.00 to 24.00% in simplex and duplex PCR systems, respectively. The relative standard deviations of the mean values for different GM content maize samples were all within 13.60% both in simplex and duplex analyses. This study showed that the detection systems of GM maize MIR604 using a new reference molecule pMIR604 as a calibrator are applicable for analysis of GM maize MIR604 and suitable for use as a preferable substitute of the reference material derived from plant raw materials.     

转基因食品 何必谈虎色变

<正> 民以食为天,转基因食品作为新型食品,其是否安全始终是人们关注的焦点,如今甚至到了谈虎色变的地步! 其到底有无危害呢,这首先需知道什么是转基因食品! 狭义上说,通过基因工程手段将一种或几种外源性基因转移至某种特定生物体(动、植物和微生物等)中,并使其有效地表达出相应的产物(多肽或蛋白质),这样的生物体直接作为食品或以其     

转基因食品及其安全性评价

随着我国转基因农作物进口数量不断增加,以转基因农作物为原料的食品在市场上所占有份额逐渐增大,转基因食品安全性越来越受到人们关注;本文综述转基因食品发展现状、安全性评价、营养问题及各国政府对于转基因食品采取的管理措施和标识管理,并对转基因食品发展前景进行展望。     

跟我学(79) 玉米薄饼

前段时间,本刊"手机短信问答"收到了一些读者发来的短信,他们都在询问2008年第11期上发表的玉米薄饼是怎么做的?本期,我们特请来制作这道小吃的师傅给大家具体地讲讲.     

转基因食品现状初析

较全面地介绍了转基因食品生产和安全性的情况 ,总结了各国的态度和管理模式 ,并初步分析了其中的原因。     

Natural maize phenolic acids for control of aflatoxigenic fungi on maize

ABSTRACT:  Natural phytochemicals may be an alternative to synthetic chemicals for controlling fungal growth and mycotoxin production in stored maize. A key to progress in this field is to select the best natural maize phytochemicals to be applied in a storage maize ecosystem. This research was undertaken to evaluate the effects of the natural phytochemicals trans-cinnamic acid (CA) and ferulic acid (FA) alone at concentrations of 20 to 30 mM and in 5 combinations on Aspergillus flavus Link and A. parasiticus Speare populations and aflatoxin B₁ production. Studies on Aspergillus population and aflatoxin B₁ production were carried out in maize grain in relation to a water activity a_w of 0.99, 0.97, 0.95, and 0.93. CA and FA at concentrations of 25 to 30 mM, respectively, and CA-FA mixture T9 (25 + 30 mM) were the treatments most effective at inhibiting A. flavus and A. parasiticus population at all a_w assayed after 11 d of incubation. At all a_w values, the mixture CA-FA T9 (25 + 30 mM) completely inhibited (100%) aflatoxin B₁ production by both strains at a_w= 0.99, 0.97, 0.95, and 0.93. Decreased aflatoxin B₁ levels in comparison with the control were observed with mixtures CA-FA T6 (10 + 25 mM), T7 (20 + 20 mM), and T8 (20 + 30 mM) of both strains in the majority of a_w assayed. The data show that CA and FA could be considered as effective fungitoxicants for A. flavus and A. parasiticus in maize in the a_w range 0.99 to 0.93. The information obtained shows promise for controlling aflatoxigenic fungi in stored maize.     

Household dietary exposure to aflatoxins from maize and maize products in Kenya

Aflatoxicosis has repeatedly affected Kenyans, particularly in the eastern region, due to consumption of contaminated maize. However, save for the cases of acute toxicity, the levels of sub-lethal exposure have not been adequately assessed. It is believed that this type of exposure does exist even during the seasons when acute toxicity does not occur. This study, therefore, was designed to assess the exposure of households to aflatoxins through consumption of maize and maize products. Twenty samples each of maize kernels, muthokoi and maize meal were randomly sampled from households in Kibwezi District of Makueni County in Eastern Kenya and analysed for aflatoxin contamination. The samples were quantitatively analysed for aflatoxin contamination using HPLC. The uncertainty and variability in dietary exposure was quantitatively modelled in Ms Excel using Monte Carlo simulation in @Risk software. Aflatoxins were found in 45% of maize kernels at between 18 and 480 μg kg^–1, 20% of muthokoi at between 12 and 123 μg kg^–1, and 35% of maize meal at between 6 and 30 μg kg^–1. The mean dietary exposure to aflatoxin in maize kernels was 292 ± 1567 ng kg^?1 body weight day^?1, while the mean dietary exposure to aflatoxin in maize meal and muthokoi were 59 ± 62 and 27 ± 154 ng kg^?1 body weight day^?1 respectively. The results showed that the amount and frequency of consumption of the three foods is the more important contributing factor than the mean aflatoxin concentration levels, to the risk of dietary exposure to aflatoxins.     

Application of QUIZ for GM quantification in food

The quantification of GM in samples can be performed without the need for certified reference materials (CRMs) using QUIZ (quantitation using informative zeros). In this work we have applied QUIZ to estimate the contents of RoundUp Ready™ soya and MON810 in processed food containing one or both GMs. Results show good agreement between derived values and known input of GM material and compare favourably with quantitative real-time PCR.     

转基因食品安全与环境分析

转基因食品可为人类的发展提供食品安全保障,它对人体健康基本是安全的。尽管转基因食品的生产与加工对生物多样性、土壤生态可能有一些影响,杀虫剂、除草剂等的使用会带来一些环境污染,但其拥有的优点也很明显。可通过完善转基因技术,降低转基因食品的不良效应,加强转基因食品的安全检测,健全转基因食品安全评价体系等措施来解决这些问题。     

Comparison of carotenoid components between GM and non-GM papaya

We compared the carotenoid profile in GM papaya (Sunup) line to that of a non-GM one (Sunset). First, to identify major carotenoids in papaya, large-scale extraction was carried out with methanol. HPLC analyses of the methanol extracts revealed that both papayas mainly contained 5 pigments and no apparent difference was observed in the HPLC profiles. On the basis of LC/MS data and photodiode-array spectra, beta-carotene (3), lycopene (2), beta-cryptoxanthin (1), and beta-cryptoxanthin myristoyl and lauroyl esters (4 and 5) were identified as major carotenoids. It is well known that most carotenoids are labile, so a rapid analysis with precautions to avoid decomposition was developed to quantify their contents in the original fruits. Frozen samples of the fruits were sliced and a piece (about 2 g) of fruit was cut out and lyophilized. After extraction of the piece with methanol containing an anti-oxidant, BHT, the extract was further partitioned with hexane and methanol. Finally the contents of the main carotenoids in the hexane fraction were analyzed by HPLC. The contents of total carotenoids (sum of 1-5) and beta-cryptoxanthin (1, 4 and 5) in GM papaya fruit were estimated to be 0.764 +/- 0.056 and 0.604 +/- 0.051 (mumol/g), respectively and those in non-GM fruit were 0.883 +/- 0.145 and 0.705 +/- 0.098 (mumol/g), respectively. These differences are not statistically significant.