SEROLOGIC IDENTIFICATION OF SPECIES OF ORIGIN OF SAUSAGE MEATS

SUMMARY: A partially purified immunoglobulin G (lgG) solution prepared from the serum of species to be tested was heated to the specifications for sausages. The resulting supernatant fluid was decanted and the precipitate washed with saline and used to immunize rabbits. The supernatant fluid was used to sensitize tanned sheep red blood cells. The immune serum was rendered monospecific by absorptions with heterologous, heated lgG precipitates. A sample of monospecific immune serum was absorbed with a washed homogenate of sausage. Aliquots of the monospecific immune serum, both untreated and sausage absorbed, were tested with cells sensitized with the homologous heated lgG supematant fluid. A significant reduction of titer by sausage absorption indicated that the sausages contained the meat homologous to the immune serum.     

SIMPLIFIED IDENTIFICATION OF YEASTS BY A SEROLOGICAL TECHNIQUE

A scheme is described for comparison of yeast colonies isolated on normal or selective media or by membrane filtration. By streak culture of each colony, or of a selection of each type of colony, on Oxoid WL medium followed by serological and morphological testing of the cultures, the different species present are detected with minimal effort. Colonies of the same species are identical in appearance, and in serological and morphological properties of the cells; therefore if a complete identification is desired, only one colony need be tested of each type. This saves the effort of fermentation and other tests on a large number of colonies, but results of morphological and serological tests alone normally provide sufficient information for identification of taxonomic groups of yeasts, if not of individual species. Three examples of the use of the method are described: identification of the various yeast species of the sherry flor complex, and identification of yeasts in samples of clean and polluted water.     

线性聚合技术制备氨基硅油

制备氨烷基分布均匀的硅油。分子量分布很窄的线状端羟基二甲基聚硅氧烷ＷＳ－６２Ｍ代替Ｄ４与氨烷基硅烷酯交换反应、聚合反应,制得氨烷基分布均匀、且无杂质的氨基硅油。解决了Ｄ４开环、聚合反应中,Ｄ３～Ｄ１２杂质、反应副产物和反应过程不合理而导致氨烷基分布不均匀、影响整理织物柔软效果的问题。该合成方法简单,收率高,工艺合理,整理织物柔软效果好。     

IDENTIFICATION OF BARLEY VARIETIES USING THE POLYMERASE CHAIN REACTION

The polymerase chain reaction (PCR) with oligonucleotide primer sequences from alpha-amylase genes was used to distinguish between morphologically similar malting and feed barley varieties. The varieties “Chebec” (feed) and “Schooner” (malting) could be separated and the varieties “Skiff” (feed) and “Franklin” (malting) were identified by using two sets of primers. Primer BSW3 (5-CAGCTTGGCCTCCGGGCAAGTC-3) and BAS2 (5-CACCTTGCCGTCGATCTC-3) gave a 215 bp product that distinguished “Chebec” from “Schooner” and a 1230 bp fragment that distinguished “Skiff” from “Franklin”. Primer BSW5 (5-GGAGCTGGAATTGATGTTG-3) with primer BAS2 gave markers at 735 bp and 730 bp respectively to allow unique identification in comparisons of these pairs of varieties. DNA extracted from grain could be used for these analyses, but DNA from leaves gave clearer results.     

基因芯片技术鉴定食源性金黄色葡萄球菌

为了建立快速鉴定食派陛金黄色葡萄球菌的基因芯片技术，采用PCR方法扩增金黄色葡萄球菌16SrRNA基因的DNA片段．序列进行BLAST比较并通过软件设计其特异性探针，采用基因芯片杂交技术鉴定食源性金黄色葡萄球菌样品。结果：对所有样品进行基因芯片杂交技术处理并扫描观察，金黄色葡萄球菌的杂交结果呈阳性，其检测结果与传统方法鉴定结果一致。结论：应用基因芯片鉴定技术可快速、准确地鉴定食源性金黄色葡萄球菌，值得推广应用。     

利用生物素链霉亲和素放大酶联免疫方法检测猪肉中莱克多巴胺残留

以酶联免疫方法为基础.结合生物素-链霉亲和素系统的放大作用,建立直接竞争生物素链霉亲和素放大酶联免疫(BA-ELISA)检测方法,并将其用于猪肉肌肉组织中莱克多巴胺残留的检测,方法灵敏度(IC50)为(0.3±0.05)ng/mL,样品检出限为(0.3+0.1)ng/kg,平均加标回收率在84%以上.     

DNA ANALYSIS FOR IDENTIFICATION OF FOOD-ASSOCIATED FOREIGN SUBSTANCES

To identify food‐associated foreign substances, a DNA analysis consisting of 18S rDNA sequencing and homology search analysis has been developed. In this method, we designed universal primer pairs for specific amplification of animal and plant 18S rDNA and constructed an original DNA database storing partial 18S rDNA sequences of 222 organisms commonly used for culinary purposes. In the model experiments, food materials were successfully identified, indicating that our DNA analysis method can be practically applied to the identification of food‐associated foreign substances. It is also expected that this method complements conventional morphological and compositional analysis, leading to more accurate and reliable identification of food‐associated foreign substances.     

IMS USING IN-HOUSE MONOCLONAL ANTIBODY-COATED MAGNETIC BEADS ASSOCIATED TO PCR ASSAY FOR DETECTION OF SALMONELLA TYPHIMURIUM IN RAW MEATS

An immunomagnetic separation (IMS) technique and a PCR assay were developed for use in detection of Salmonella Typhimurium in meat samples. To prevent false-negative results, an internal amplification control was developed. The polymerase chain reaction (PCR) using primers specific for an omp gene sequence of Salmonella spp has shown 100% sensitivity and specificity and a detection limit of 10⁴ cfu/mL. The IMS-PCR methods using PCR immediately after IMS and using 6 h postenrichment in brain heart infusion between IMS and PCR resulted in detection limits of 10³ cfu/mL and 1–10 cfu/mL, respectively. The lowest level of S. Typhimurium that could be detected by the IMS-PCR method in the presence of natural microbiota from inoculated meat samples was 1–10 cfu/25 g. When samples were analyzed using enrichment protocols without IMS, several false-negative results were obtained.

PRACTICAL APPLICATIONS

The immunomagnetic separation-polymerase chain reaction (IMS-PCR) method developed enabled a rapid and sensitive detection of Salmonella Typhimurium in inoculated meat samples. Monoclonal antibody (Mab)-coated magnetic beads prepared in-house were efficient in concentrating and separating the bacteria from the food matrix, thus improving detection limit and avoiding false-negatives. The internal amplification control (IAC), now mandatory in PCR assays, using the same primers of the target DNA further prevented false-negative results. Therefore, the IMS-PCR method developed in this study could be used in the future by the Brazilian food industry as a substitute for the expensive imported kits for Salmonella detection in foods. We are now developing a panel of Mabs against conserved antigens of Salmonella for use in the IMS-PCR method in order to extend its applicability for detection of other serovars.     

Identification of Aloe species by random amplified polymorphic DNA (RAPD) analysis

Juice and integument of leaves of 3 Aloe species, Aloe vera, A. ferox and A. africana, are not allowed to be used as food according to the Pharmaceutical Affairs Law in Japan. On the other hand, whole leaves of A. arborescens can be used as food. The present study was designed to distinguish Aloe species by random amplified polymorphic DNA (RAPD) analysis. DNA was isolated from fresh and dried leaves of the 4 Aloe species. Five out of 32 different 10-mer primers examined were useful for analysis. By comparison of the characteristic bands of PCR products on agarose gel, it was possible to distinguish the 4 species. Thus, the botanical species of Aloe in commercial food products can be identified by RAPD analysis.     

涤纶超细纤维的生产技术──（一）设备

本文主要介绍了德国ＨＥＵＭＡＧ公司采用ＰＯＹ－ＤＴＹ工艺路线生产涤纶超细旦预取向丝（ＰＯＹ）的生产设备状况。     

C60的重要技术价值及其潜在应用前景

1985年C60的发现是对碳认识的新阶段，是科学上的重要发现，使我们了解到一个全新的碳化学世界。短短的10多年来，C60已经广泛地影响物理学、化学、材料学、生命学及医药科学等领域，极大丰富和提高了科学理论，同时也显示出巨大的潜在应用前景。     

IDENTIFICATION OF GOAT MEAT USING HIGHLY SPECIES‐SPECIFIC POLYMERASE CHAIN REACTION

ABSTRACT

A highly species‐specific polymerase chain reaction (PCR) assay was developed for the authentic identification of goat. A product of 436 bp was amplified using newly designed primers against mitochondrial D‐loop region. The possibility of cross‐amplification was ruled out by considering as many as 25 other animal species. Suitability of the developed goat species‐specific PCR assay was confirmed for in raw, cooked (60, 80 and 100C for 30 min) and micro‐oven‐processed meat samples (n = 20 each). A sensitivity of 0.1% was established for detection of adulteration and limit of detection of goat DNA was 0.1 pg. This investigation presents a novel PCR assay with its newly designed primers that could be used for the authentic identification of goat species.

PRACTICAL APPLICATIONS

This work details about a novel diagnostic polymerase chain reaction, which could be used for authentic identification of goat species. This approach could be used for the confirmation of goat tissues in raw, cooked, as well as adulterated samples. The developed technique has also applications in the forensic analysis of wild animal‐related disputes, where this work could solve the problem of goat‐related issues.     

I. DETERMINATION OF BARLEY AND MALT NITROGEN CONTENT USING AN AUTOANALYSER TECHNIQUE

A rapid semi-micro method of Kjeldahl digestion and the use of an Autoanalyser for the estimation of digest ammonia content are described. Adoption of these methods has achieved throughput rates of 40 to 50 samples per hr. with resultant savings in labour and materials.     

单核细胞增生性李斯特菌毒力基因检测及DNA随机扩增多态性分型

为了解在昌平地区分离的单核细胞增生性李斯特菌（Lm）携带毒力基因的状况和DNA随机扩增多态性（RAPD）分型情况，采用聚合酶链反应（PCR）对28株加进行了溶血素基因（hfy）、与侵袭性有关的卸和prfA基因的测定及RAPD分型。结果3个毒力基因PCR全部呈阳性反应，两株无害加为阴性反应。用RAPD分型，28株加分为12型．A、B两型共9株菌全部来自某肉联厂；C、D两型共10株来自某肉鸡公司；另外9株加有8个RAPD型．分别来自熟肉制品及零售市场。此次实验发现昌平地区在不同时间、不同地点分离的加其RAPD型别变化较大。有多种型别的细菌存在。根据RAPD分型看出肉联厂与肉鸡公司可能存在着内部污染问题。