Discrimination of Korean beef from beef of other origin by stable isotope measurements

Beef samples from Korea and from some of the main beef exporting countries (USA, Mexico, Australia, New Zealand) were analysed for carbon, nitrogen and hydrogen isotope ratios of the defatted dried matter. Results showed that the samples from each country investigated could be assigned to a typical isotope signature and can be separated from each other. The main discriminating factors were δ¹³C and δ²H, which mainly reflect feeding of C₃ and C₄-plants and the isotopic composition of the water, respectively, consumed by the cattle. Australian beef showed the largest variation in its isotopic signature, suggesting heterogeneous rearing conditions. By contrast, for beef from New Zealand, Mexico, USA and Korea, each batch had typical signatures with a smaller variability.     

Authentication of organic and conventional eggs by carotenoid profiling

Organic production benefits from fair competition and sustained consumer confidence. The latter can only be assured by paper trailing and verification assessments. Traditional analytical strategies for guaranteeing quality and uncovering adulteration have relied on the determination of the amount of a marker compound or compounds in a material and a subsequent comparison of the value(s) obtained with those established for equivalent material. Since it is unlikely to find a unique marker that allows discrimination between organic and conventional produce, selective fingerprinting (profiling) combined with chemometrics is a more promising approach. In this study, carotenoid High Performance Liquid Chromatography–Diode Array Detection profiling combined with k-nearest neighbour classification chemometrics was used to predict the production system (organic vs. non-organic) of chicken eggs. A proof-of-concept set (training set for the model) was composed of eggs from 24 organic farms, 12 free range, and 12 barn farms in the Netherlands. The identities of organic, free range, and barn eggs were predicted with success rates of 100%, 100%, and 84%, respectively. The identity of eggs determined using an additional market test set with eggs from 12 organic, 12 free range, and 12 barn farms originating from the Netherlands and New Zealand resulted in correct classifications for 35 of the 36 samples. The results of this study indicate that this fingerprint approach is a promising tool for analytical verification of the production system of organic eggs.     

Intra-muscular and inter-muscular variation in carbon turnover of ovine muscles as recorded by stable isotope ratios

In the case of muscle-based foods, the incorporation of dietary isotopic signals into muscle tissue is a dynamic process and it is not known whether all muscles, or locations within a muscle, have the same isotopic composition. Therefore, an experiment was conducted in which 28 lambs were switched from a control diet to an isotopically distinct experimental diet offered at two different energy allowances (EA). Small, albeit significant, differences were detected in tissue carbon (C) turnover within the muscle Longissimus dorsi. Inter-muscular comparison showed similar C half-lives for four of the five analysed muscles. The results also clearly demonstrated that the EA had a significant impact on intra- and inter-muscular C turnover. The findings of similar tissue C turnover of several muscles sold as meats and the comparable tissue-diet fractionation of the analysed muscles (both within the same EA) will enable scientists to analyse different meat samples according to availability without introducing large biases. However, EA must be considered a factor of uncertainty.     

明式家具的实用内涵初探

明式家具中凝聚着实用内涵和精神内涵,保持着实用与审美的统一,具有强烈的实用美学特征。本文从明代畅行的“经世致用”的实用主义思想出发,阐述了明式家具的实用内涵,把传统经验和现实生活作为明式家具实用内涵的基础,由于这种实用性特征,明式家具走进了人们的日常生活中,实现了家具艺术的通俗化。     

Detection of bovine DNA in raw and heat-processed foodstuffs, commercial foods and specific risk materials by a novel specific polymerase chain reaction method

The identification of beef in animal foods is a major concern not only for the prevention of commercial fraud, but also to avoid safety risks deriving from the presence of prohibited bovine material that might be harmful to both human and animal health. Here we report a novel set of bovine-specific primers, CYTbos1 (forward) and CYTbos2 (reverse), which allow the specific amplification of a 115 base pair fragment of the bovine cytochrome b gene (cytb) between nt 844 (mitochondrial site 15,590) and nt 958 (mitochondrial site 15,704), no cross-reaction being observed with DNA from another 12 frequent commercial meat species. The polymerase chain reaction product obtained is cleaved specifically by endonucleases ScaI and TspE1 to achieve further confirmation evidence. The sensitivity of the proposed method was 0.025%. The CYTbos primers successfully detected bovine DNA in meat samples processed for 20 min at 133 °C/300 kPa or for 2 h at 121 °C. CYTbos primers also detected bovine DNA in heat-processed commercial meat products exhibiting a complex nature, as well as in bovine specific risk materials. The proposed polymerase chain reaction method, aimed at detecting a small and specific fragment of the bovine mitochondrial DNA, may be especially useful for the direct identification of bovine DNA in foodstuffs subjected to severe heating under overpressure conditions.     

稳定同位素技术在有机农产品真实性鉴别中的应用进展

近年来, 有机农产品深受消费者的青睐, 然而在经济利益驱动下, 无良商家伪造有机农产品的现象时有发生, 使得有机农产品的真实性问题逐渐成为全球关注的焦点。有机农产品真实性鉴别对确保食品质量安全, 保护合法经营, 重建我国消费者对有机农产品的信任, 完善有机农产品质量监督体系均具有十分重要的意义。稳定同位素技术是用于有机食品真实性鉴别的方法之一, 具有高效、准确、可靠的特点, 已广泛应用于蔬菜、水果、茶叶、葡萄酒、谷物、鸡蛋、肉类、牛奶等。本文在查阅大量有关稳定同位素技术在有机农产品真实性鉴别的相关文献的基础上, 总结了稳定同位素鉴别有机农产品的原理, 系统分析了近几年国内外学者关于稳定同位素技术在植物源性和动物源性有机农产品的研究进展, 并展望了今后稳定同位素在有机农产品真实性鉴别的研究重点和发展方向。     

Review of Cultural Heritage Authenticity and Tourism Devel-opment

This paper tries to explore in a systematic way the internal relationship of authenticity and the sustainable development of heritage tourism, so as to bring some in-depth thoughts to readers on the development of China’s heritage tourism. Firstly, the original concept of authenticity and cultural heritage are discussed from the areas of heritage science and tourism science. Secondly, the relationship between cultural heritage protection and authenticity are discussed from two aspects which are the criticism of “inauthenticity” of tourism and the value of heritage conservation in tourism. Thirdly, the literature of authenticity and cultural heritage development are reviewed, including the heritage development based on cultural heritage authenticity and the heritage development based on tourists’ authentic experience. At last, the researches on authenticity and cultural heritage tourism man-agement are summarized in terms of management model and related interests bodies.     

Authenticity Assessment of Extra Virgin Olive Oil: Evaluation of Desmethylsterols and Triterpene Dialcohols

Extra virgin olive oil (EVOO) has a long history of economic adulteration, the detection of which presents significant challenges due to the diverse composition of cultivars grown around the world and the limitations of existing methods for detecting adulteration. In this study, using Method COI/T.20/Doc. No. 30/Rev. 1 of the International Olive Council, the authenticity of 88 market samples of EVOO was evaluated by comparing total sterol contents, desmethylsterol composition, and contents of triterpene dialcohols (erythrodiol and uvaol) with purity criteria specified in the United States Standards for grades of olive oil and olive‐pomace oil. Three of the 88 samples labeled as EVOO failed to meet purity criteria, indicating possible adulteration with commodity oil and/or solvent‐extracted olive oil. Detection of adulteration was also evaluated by spiking an EVOO sample with commodity oil at the 10 % level. As expected, eight of the spiked samples (canola, corn, hazelnut, peanut, safflower, soybean, and sunflower oils, and palm olein) failed to meet purity criteria. Two of the three samples spiked with 10 % hazelnut oil went undetected for adulteration. Overall, a low occurrence rate of adulteration (<5 %), based on purity criteria for desmethylsterols and triterpene dialcohols, was detected for the 88 products labeled as EVOO.     

Verifying the geographical origin of poultry: The application of stable isotope and trace element (SITE) analysis

Stable isotope and elemental analysis, together with statistical processing of the resultant data has been used to determine the geographical origin of poultry and hence provide a means to verify poultry labels originating from major producing countries/regions. Multivariate statistical analysis has demonstrated that 18 variables, including carbon, hydrogen and nitrogen stable isotope ratios and elemental concentrations of magnesium, thallium, rubidium and molybdenum, are important parameters in poultry origin determination. Using cross-validated discriminant analysis 88.3% of poultry geographical origins were correctly classified (n = 339). Individual correct-classification rates were as follows; China, 100% (n = 36); Brazil, 94.1% (n = 101); Europe 92% (n = 87); Chile 82.6% (n = 46); Thailand, 70.3% (n = 46) and Argentina 50% (n = 10). The main identification errors were associated with miss-classification of Argentinean samples with those originating from Chile and Thailand. Carbon stable isotope ratios of chicken meat indicate the quantity of maize in the diet and this leads to useful discrimination between a large proportion of European poultry and poultry reared in locations such as South America, Thailand and China where maize feeding predominates. The use of poultry carbon isotope values as a simple ‘screening’ parameter to differentiate European poultry meat from other major importers is not as reliable as for the differentiation of European and South American beef. However carbon isotope ratios will be useful in most instances to corroborate suspicion of mislabelling of non corn-fed European poultry. The stable isotopes of hydrogen and oxygen in chicken meat change in a similar way to surface waters around the globe. Our findings support the hypothesis that the global isotopic variation of stable isotopes in drinking water and feed are transferred into animal tissue and can be used to help establish an animal's geographic origin. This is a significant finding and mirrors our observations for beef skeletal muscle δ²H ‰ and δ¹⁸O ‰ values. These systematic variations can be exploited to give a ‘low-resolution’ indication of an animal's geographic origin (e.g. Northern Europe versus the tropics).     

The use of multi element profiling to differentiate between cowand buffalo milk

The multi element profile of milk from 12 cows and 6 water buffaloes was investigated, to establish whether dairy products derived from the two species could be distinguished. Multi-element data were obtained using ICP-MS. Following assessment against the team’s QA/QC criteria, or where the levels were below the LOD for the procedure, 16 elements (P, S, K, Ca, V, Cr, Mn, Fe, Co, Zn, Ga, Rb, Sr, Mo, Cs and Ba) were submitted for statistical analysis. Using linear discriminant analysis (LDA) it was possible to differentiate between milk from the two species, produced under identical environmental and animal husbandry conditions, on one farm. The sources of food and water available for consumption by the animals were also analysed and the results showed that there was no correlation between the elemental composition of the dietary components and the profiles observed in the milk.