Sensory Evaluation and Acceptability of Cookies Enriched with Sweet Lupine Flour (Lupinus albus cv Multolupa)

Cookies enriched with 0, 5, 10, 15, 20, and 25% full-fat sweet lupine flour (FFSL) were evaluated by a sensory panel using the rank of preference and paired comparison tests. Cookies with 0, 5, and 10% FFSL were preferred while those containing 20 and 25% FFSL were rejected (p≤0.01). Studies conducted with school children showed similar acceptability for 0 and 10% FFSL-containing cookies which was different (p = 0.05) from those containing 20% FFSL. Fortification of the basic formula with 10% FFSL was recommended on the basis of acceptability.     

Development of an Indirect Competitive ELISA Kit for the Detection of Soybean Allergenic Protein Gly m Bd 28K

The complementary DNA (cDNA) sequence of Gly m Bd 28K was expressed in Escherichia coli BL21 (DE3) as an inclusion body under the induction of 1.0 mmol/L of isopropyl β-D-thiogalactoside (IPTG). The inclusion bodies were solubilized in 6 M guanidine hydrochloride and refolded by rapid dilution. After renaturation, the purity of the recovered recombinant protein was up to 90 %, and its molecular weight was 29.1 kDa. A monoclonal antibody that was specific for recombinant Gly m Bd 28K protein was produced and characterized. Based on the mAb, an indirect competitive enzyme-linked immunosorbent kit (icELISA kit) for the specific detection of recombinant Gly m Bd 28K protein was developed, which showed that the IC₅₀ was 3.19 μg/L and the sensitivity was 0.235 μg/L. The average relative standard deviation (RSD) was 10.28 %, and the average recovery was 96.73 %, which indicated that the kit was highly sensitive and accurate. The icELISA kit remained usable for more than 6 months when stored at 4 °C. Therefore, the icELISA is a valuable tool for the rapid and sensitive detection of Gly m Bd 28K in food and feed products from soybeans.     

Development of a Competitive ELISA for the Detection of Pecan (Carya illinoinensis (Wangenh.) K. Koch) Traces in Food

Pecan nuts are included among the so-called big-eight food allergens, which are responsible for 90% of food allergies. However, unlike other tree nuts such as Brazil nut and hazelnut, studies on pecan from the point of view of allergies are scarce, and only a few analytical methods to detect its presence in food have been published. The objective of the present study was to develop an enzyme-linked immunosorbent assay (ELISA) method to detect traces of pecan in foods. Therefore, pecan-specific polyclonal antibodies were developed in rabbits and characterized for their specificity to pecan proteins and for their selectivity in challenging studies with other food ingredients and allergens. In addition, the research was complemented with more specific analyses like sodium dodecyl sulfate polyacrylamide gel electrophoresis to characterize the protein standard and western blot to identify the reactive proteins. By applying the selected conditions, the data were fitted to a four parameter logistic curve, which gave a R square of 0.999, and IC50 and IC80 values of 5.0 and 2.2 ng/mL, respectively. This highly sensitive method allows the detection of trace amounts of pecan protein within complex food matrices, which can provide the food industry with a useful tool to comply with the requirements enforced by regulatory agencies.     

Sandwich Enzyme‐Linked Immunosorbent Assay (ELISA) for the Detection of Lupine Residues in Foods

ABSTRACT: Lupine has been increasingly used in food applications due to its high nutritional value and excellent functional properties. However, lupine provokes allergic reactions in susceptible individuals. The presence of undeclared lupine residues in foods can pose a serious health risk to lupine‐allergic individuals. Therefore, the objective of this research was to develop a sandwich‐type ELISA for the detection of lupine residues in foods. Lupine flour derived from Lupinus albus was used to immunize 3 rabbits and a sheep. Pooled lupine‐specific antibodies were partially purified from the sera by ammonium sulfate precipitation. A sandwich lupine ELISA with a limit of quantification (LOQ) of 1 ppm was developed by utilizing the rabbit antisera as the capture reagent and the sheep antiserum as the detector reagent. The binding of the antigen‐antibody complex was visualized by the addition of commercial rabbit antisheep IgG antibody labeled with alkaline phosphatase with subsequent addition of p‐nitrophenyl phosphate substrate to produce a colored product for quantification. Minor cross‐reactivity was observed with soy (Glycine max) and black bean (Castanospermum australe). The performance of the lupine ELISA was evaluated in reference food standards (beef frankfurter and apple cinnamon muffin) and laboratory‐prepared cooked frankfurters and corn muffins. The mean percent recovery for lupine spiked‐frankfurters and corn muffins were 108.4%± 8.8% and 103.1%± 11.5%, respectively. The sandwich‐type lupine ELISA developed in this study provides food manufacturers and regulatory agencies with an effective analytical tool to detect and quantify lupine residues in processed foods.     

食品安全快速检测方法评价技术研究进展

快速检测方法在食品安全领域现场检测、快速筛查和政府监管等方面起着非常重要的作用。然而当前市场上基于快速检测方法的产品还存在着质量参差不齐,使用方法不科学等诸多问题,亟需建立科学合理的快检产品评价方法,保障产品质量和指导实际使用。本文综述了国内外对快速检测方法（产品）评价技术的现状与进展,并结合粮油质量安全领域中的实际情况探讨其应用情况。     

两种致病性弧菌二重LAMP-熔解曲线检测方法的建立

应用环介导等温扩增技术(Loop-mediated isothermal amplification,LAMP),建立了食品中产毒素性霍乱弧菌和副溶血性弧菌二重LAMP-熔解曲线快速检测方法。本方法针对产毒素性霍乱弧菌ctx A基因和副溶血性弧菌gyr B基因分别设计引物组进行二重LAMP扩增,并利用熔解曲线法分析扩增产物,从而判断DNA模板中所含目标菌。应用本方法对9株目标菌和17株非目标菌的检测结果与预期一致,并可通过熔解曲线的特征峰准确分析DNA模板中所含目标菌。对二重LAMP扩增产物的测序分析表明,扩增所得序列与目的基因序列吻合,从而进一步验证了该方法的特异性。经测试,本方法对两种目标菌的检测灵敏度均可达100 fg DNA/反应管。实验证明所建立的方法具有良好的特异性,并可为食品中两种致病性弧菌的快速检测提供一种重要技术手段。     

食品中过敏原胡桃蛋白间接竞争ELISA检测方法研究

胡桃是坚果类食品中引起过敏反应的首要食品。采用胡桃总蛋白产生的多克隆抗体,建立检测胡桃成分的间接竞争ELISA方法,并通过特异性试验和样品回收试验对该方法进行验证。结果表明:该方法对胡桃蛋白的定量检测限(LOQ,相当于IC80)为94 ng/mL;在特异性试验中,只有美洲山核桃出现交叉反应,其它植物样品均未出现交叉反应;将50~1 000 ng/mL〔相当于10~200μg/g〕的胡桃蛋白添加到小麦蛋白中,胡桃蛋白的回收率在78%~93%之间。     

LAMP法检测食品中凝固酶阳性葡萄球菌

建立凝固酶阳性葡萄球菌环介导等温扩增方法(LAMP),运用在食品样品检测中,与实时荧光PCR方法及国家标准检测方法进行比较。以毒力因子——凝固酶的编码基因coa为目的基因设计引物,建立环介导等温扩增方法,对9株凝固酶阳性葡萄球菌和31株对照菌(均为凝固酶阴性)进行测试,并对5种共1 341份食品进行检测。建立的方法具有很好的特异性,检测灵敏度可达到1.8 CFU/100 g～2.5 CFU/100 g。     

基于图像识别技术的食品种类检测方法

针对食品质量参差不齐、真假互掺的现状,提出基于图像识别技术的食品种类检测总体设计方案。详细分析图像识别技术的处理过程,包括图像获取、图像预处理及特征提取和图像特征参数计算三大部分。最后以红枣种类识别检测为例,对食品种类检测系统设计及实现进行说明,结果证明该设计方案能够用于实际食品检测工作中。     

食品防腐剂的分析方法研究进展

添加于食品中的防腐剂,如果超范围超量使用会对人体食用后造成潜在的危害。为了监控防腐剂滥用,科研人员建立了许多有效的检测方法。目前,这些方法各有长处,能够基本满足社会的需求。文章对食用合成防腐剂的分析方法作了全面的综述。     

食物中过敏原的体外检测

食物过敏是世界范围内出现的严重的公共健康问题。复杂食物样品中微量过敏原的检测和定量在今天依然是食品工业的一个巨大挑战。开发和建立完善的过敏原检测分析方法可以有效的防止致敏物质对食物链的污染,引导消费者避免过敏性成份。该文综述了过敏原体外检测和定量的常用方法,同时重点介绍了目前的一些新型检测技术及研究进展。     

环介导等温扩增技术检测食品中铜绿假单胞菌

建立食品中铜绿假单胞菌环介导等温扩增(LAMP)检测方法。利用铜绿假单胞菌外毒素A(PEA)基因序列,设计3对铜绿假单胞菌LAMP检测特异性引物,用36株铜绿假单胞菌,14株近源菌验证方法的特异性。建立的LAMP方法特异性好,灵敏度达到2.2 cfu/100 g~3.5 cfu/100 g。建立的食品中铜绿假单胞菌LAMP检测方法特异性好,灵敏度高,适用于的检测食品中的铜绿假单胞菌。     

Development of a Sandwich Enzyme-Linked Immunosorbent Assay (ELISA) for Detection of Buckwheat Residues in Food

Abstract: Buckwheat is a pseudocereal (an eudicot with seed qualities and uses similar to those of monocot cereals, family Poaceae) that is consumed in some Asian countries as a staple, and in some western countries as a health food. Allergic reactions to buckwheat are common in some countries. The objective was to develop a specific and sensitive sandwich enzyme-linked immunosorbent assay (ELISA) to detect traces of buckwheat that might inadvertently contaminate other foods in order to assure accurate labeling and consumer protection. Buckwheat-specific antibodies produced in 3 species of animals were tested for specificity and titer by direct ELISA and immunoblot. A sandwich ELISA was developed utilizing pooled rabbit antibuckwheat sera to capture buckwheat proteins and pooled goat antibuckwheat sera, followed by enzyme-labeled rabbit antigoat immunoglobulin G (IgG), to detect bound buckwheat proteins. The lower limit of quantification (LOQ) of the sandwich ELISA was 2 parts per million (ppm) of buckwheat in the presence of complex food matrices. The ELISA is highly specific with no cross-reactivity to any of 80 food ingredients and matrices tested. Validation studies conducted with buckwheat processed into noodles and muffins showed greater than 90% and 60% recovery, respectively. The percent recovery of buckwheat from noodles was similar to that achieved with a commercial buckwheat ELISA kit (ELISA Systems Pty. Ltd., Windsor, Queensland, Australia) at high buckwheat concentrations. However, the sensitivity of this ELISA was greater than the commercial ELISA. This newly developed ELISA is sufficiently specific and sensitive to detect buckwheat residues in processed foods to protect buckwheat-allergic subjects from potential harm. Practical Application: Buckwheat is becoming a common food ingredient in a number of processed foods due to potentially beneficial nutritional properties, without the celiac disease inducing glutenin proteins of wheat and related cereals. However, buckwheat causes allergy in some individuals and must be labeled and tested accurately to protect those with allergy to buckwheat. We describe the development of a new test assay to help food producers ensure that buckwheat is not present in foods that are not intended to contain buckwheat.     

Loop-Mediated Isothermal Amplification (LAMP) for the Detection of Salmonella in Food

Salmonella infection represents a considerable global burden, with significant health and economic impacts. Salmonellosis is most often attributed to the consumption of contaminated foods such as poultry, beef, pork, eggs, milk, seafood, nut products, and fresh produce. Increased public awareness related to food-borne contamination resulted in greater efforts to develop more sensitive, rapid, and inexpensive methods of pathogens detection. Loop-mediated isothermal amplification (LAMP) constitutes a promising solution for rapid diagnosis of food-borne pathogens and is increasingly been applied for the specific diagnosis of different pathogens, Salmonella included. We have reviewed the application of LAMP for the specific detection of Salmonella in food matrices, compared with conventional culture techniques, and in terms of applicability, food matrices, type of assays, target genes, assay temperature, time and equipment, specificity, sensitivity, and robustness. The pros and cons of Salmonella LAMP assays are presented. The potential of LAMP for the development of new on-site diagnostics for the food and agricultural industries and its use as a routine Salmonella screening tool are discussed. Salmonella-specific LAMP assays are expected to provide a very robust, innovative, and powerful molecular diagnostic method for food safety testing services and public health authorities.     

食品中3种致病李氏菌MPCR-DHPLC检测方法的建立

应用复合PCR(multiplex PCR,MPCR)结合变性高效液相色谱(denaturing high-performance liquid chromatography,DHPLC)技术建立食品中单核细胞增生李斯特菌、绵羊李斯特菌和英诺克李斯特菌的快速高通量检测方法。根据单核细胞增生李斯特菌、绵羊李斯特菌和英诺克李斯特菌的特异基因序列分别设计引物,MPCR扩增的产物经DHPLC技术进行快速检测。以94株参考菌株做特异性实验,并开展了重现性检测实验。MPCR-DHPLC方法同步检测到单核细胞增生李斯特菌、绵羊李斯特菌和英诺克李斯特菌的特异性阳性吸收峰,未检测到李斯特菌属其他近源种和非近源种参考菌株的阳性吸收峰,且重现性良好。该方法具有很好的特异性,可以快速、准确、高通量地检测食品中单核细胞增生李斯特菌、绵羊李斯特菌和英诺克李斯特菌,是食品微生物快速检测的新技术。     

Preparation of Artificial Antigen and Development of Indirect Competitive ELISA Based on Chicken IgY for the Detection of Acid Orange II in Food Samples

To evaluate the feasibility of specific egg yolk antibodies (IgY) technology for the detection of hazardous chemical residues in foodstuffs, IgY were generated to detect acid orange II (AO2) residues. Bovine serum albumin (BSA) was made to bind with AO2 by succinic anhydride (SA), and the conjugate was used to immunize the laying chickens. PEG-6000 precipitation was used to extract IgY antibodies. The titer of anti-AO2 IgY attained the peak (1:12,800) after fifth booster immunization. Checkerboard titration showed that 1:640 dilution of anti-AO2 IgY could approximately give an optical density (OD) 1.0 at 5 μg/mL AO2-OVA coating concentration. The anti-AO2 IgY based indirect competitive ELISA (ic-ELISA) showed that the IC₅₀ value of anti-AO2 IgY was 10.72 μg/mL and regression curve equation was y?=?24.41?×?+75.11 (R ²?=?0.946). The ic-ELISA showed less cross-reactivity in range between 0.09 and 21.07 %. Recoveries from dried bean curd, sausage, and chilli powder samples were from 78.80 to 152.90 %, with relative standard deviation lower than 19.13 %. The study suggests that generated anti-AO2 IgY antibodies could be used in routine screening analysis of AO2 residues in food samples.     

食品中三聚氰胺的检测技术现状与展望

本文论述了三聚氰胺的理化性质,用途、代谢、危害以及现有的食品中三聚氰胺的各种检测技术和研究进展.     

雌二醇间接竞争酶联免疫吸附方法的建立

建立食品中雌二醇免疫分析方法。将雌二醇进行结构改造合成半抗原并经过核磁氢谱和红外光谱验证,再采用活泼酯法与载体BSA和OVA偶联制备人工抗原,免疫兔子制备多克隆抗体,经过反应条件优化建立间接竞争酶联免疫吸附检测方法。结果表明：IC50为3.9ng/mL,检测限为0.3ng/mL,交叉反应率均小于1.21%。检测方法具有高灵敏度和特异性,可应用于食品中雌二醇检测试剂盒的研制。     

河豚毒素直接竞争ELISA检测方法的研究

本研究应用直接竞争ELISA法对河豚毒素(tetrodotoxin,ITX)进行快速检测.用过碘酸钠氧化法合成酶标记抗原HRP-OVA-TTX),用直接ELISA方法对合成的酶标记抗原进行鉴定表明其与抗TTX单克隆抗体具有特异性反应.在此基础上建立了包被单抗的直接竞争ELISA方法.该方法对TTX的检测限可达到1.1μg/L,IC50为20.4μg/L,线性范围3.3～137μg/L,批内变异系数小于6.25%,批间变异系数小于7.34%.对鲫鱼的肌肉组织添加TTX标准品,回收率为65%～93.2%,变异系数为9.41%～12.77%.     

Validation of a Duplex Real-Time PCR for the Detection of Salmonella spp. in Different Food Products

A 5′ nuclease duplex real-time polymerase chain reaction (PCR) assay was developed and validated with various food products for the specific and fast detection of Salmonella spp. in food. The assay used previously published primers in combination with a newly developed probe targeting the invA gene. An internal amplification control, which is coamplified in a duplex PCR, was included in the assay. The analysis of 1,934 natural food samples with real-time PCR and the cultural method in parallel resulted in a relative accuracy of 100% and 99.84% respectively, depending on the enrichment procedure in which buffered peptone water and selective enrichment in Rappaport–Vassiliadis (RV) broth were employed. The duplex real-time PCR assay has proven to be a specific, sensitive and fast screening method for Salmonella spp. in food. The overall analysis time of the PCR method was approximately 28 h, in contrast to 4 to 5 days with conventional Salmonella diagnostics. The developed assay has been shown to be a reliable diagnostic tool for use in routine analysis. It has been validated thoroughly and has become an official method in Germany for the detection of Salmonella spp. in food.