Simple and rapid methods for detecting Salmonella enteritidis in raw eggs

The Centers for Disease Control and Prevention estimates there were 300,000 cases of Salmonella enteritidis (SE) in 1997. Egg products were associated with many of the cases. To address this problem, many producers implemented flock surveillance of the SE situation at their facilities. A rapid and simple method for detecting SE from poultry samples is critical for the effective implementation of such testing strategies. A lateral flow device for the detection of SE utilized in this study was manufactured by Neogen, Lansing, MI. The test panel is a presumptive qualitative test system that detects only members of Group D1 Salmonella species. A series of studies were conducted to optimize the test procedure for raw eggs with different sample preparations. A novel antigen extraction method was developed for use with the test panel kit. The detection limit of the test panel kit was increased approximately tenfold when the extraction method was used. Detection of SE was 100% in raw egg pools inoculated with 10 SE cells per ml of egg and incubated at a 1:10 ratio in buffered peptone water (BPW) or tetrathionate brilliant green broth (TBG) for 24 h at 37 degrees C. The developed lateral flow test kit could provide a simple, rapid, and inexpensive method for egg producers and processors to test specifically for Salmonella group D1 serovars, such as SE, in egg samples.     

Comparison of homogenization methods for recovering Salmonella Enteritidis from eggs

For Salmonella Enteritidis (SE) detection, shell eggs have been homogenized with stomachers, with electric blenders, and by hand massaging. However, to date, there have been no published reports addressing whether the method of homogenization affects the recovery of SE from raw eggs. Three inoculum levels (10, 126, and 256 SE cells per pool of 10 eggs) were used to conduct three experiments. The 10-egg pools were homogenized by one of four homogenization methods--mechanical stomaching, electric blending, hand massaging, and hand stirring-for 30 s. The homogenized eggs were then incubated at 37 degrees C, and SE colonies were enumerated after 24 and 48 h of incubation. After 24 h of incubation, no SE was recovered from egg samples from stomached or electrically blended pools inoculated with <10 cells, while levels of 106 CFU/ml were found for samples from whipped or hand-massaged pools inoculated with <10 cells. Similarly, after 24 h of incubation, the numbers of SE cells recovered from hand-massaged or hand-stirred egg pools inoculated with 126 cells were significantly larger than the numbers recovered from stomached or electrically blended egg pools inoculated with 126 cells. The number of SE cells recovered from samples homogenized with a blender was still significantly smaller than the numbers recovered from samples homogenized by the other three methods when the inoculum level was increased to 256 CFU per pool. However, the SE count for all samples approached 9 log10 CFU/ml after 48 h of incubation. It is concluded that the detection of small SE populations in shell egg samples could be improved with the use hand massaging and hand stirring for homogenization.     

Trace metal content of chicken eggs.

Results are presented for the levels of cadmium, chromium, cobalt, copper, iron, lead, manganese, mercury, nickel and zinc in each of 100 shelled chicken egg samples, as determined by atomic absorption spectrophotometry. The range and mean for each of the trace metals are as follows: cadmium, n.d. to 0.03 and 0.01 parts/million; chromium, n.d. to 0.15 and 0.06 parts/million; cobalt, n.d. to 0.06 and 0.03 parts/million; copper, 0.54 to 0.88 and 0.66 parts/million; iron, 17.1 to 27.5 and 21.5 parts/million; lead, n.d. to 0.08 and 0.01 parts/million; manganese, 0.14 to 0.53 and 0.29 parts/million; mercury, 0.001 to 0.023 and 0.006 parts/million; nickel, n.d. to 0.35 and 0.04 parts/million; zinc, 10.7 to 18.4 and 14.6 parts/million. No apparent differences were observed among the different regions of the country.     

Determination of cholesterol in Italian chicken eggs

Chicken eggs represent a relevant diet source of cholesterol. With the aim of evaluating the cholesterol content of the eggs from Campania Region (Italy) and to test a new analytical procedure, a sample of 100 chicken eggs from local market was analysed by gas chromatography using a polar capillary column. The total free cholesterol was extracted from the egg yolk with n-hexane and trichloroacetic acid, and analysed without the saponification step commonly used. This alternative procedure was compared with the official method. The results indicate that the total free cholesterol content is in the range of 120-193 mg/egg (average value 157 ± 3 mg/egg) lower than the previously reported value of 213 mg/egg. The total free cholesterol quantity is not related to the yolk weight. The bound cholesterol contribution to the total cholesterol was negligible. Dietary recommendations aimed at restricting the egg consumption should be taken with caution and should not include all individuals.     

Preparation of high affinity antibody for ribavirin with new haptens and residue analysis in chicken muscle,eggs and duck muscle

In this work, high affinity polyclonal antibodies for ribavirin (RBV) from new haptens were prepared and were used to analyse RBV residues in chicken muscle, eggs and duck muscle. The new haptens were synthesised with different spacers, and the best antibody was obtained with an IC₅₀ value as low as 0.61 ng/mL in indirect competitive enzyme-linked immunosorbent assay (ELISA). The cross-reactivities with another five antiviral drugs including amantadine, rimantadine, moroxydine, zanamivir and oseltamivir were less than 0.1%, which indicated the good specificity of the antibody. An ELISA was developed based on the antibody and applied to detect RBV in multi-food matrices. The sample preparation prior to detection only needed simple dilution after trichloroacetic acid extraction. The limits of detection were 1.07, 1.18 and 1.03 μg/kg in chicken muscle, eggs and duck muscle, respectively. Recoveries ranged from 89.0% to 112.7% with coefficients of variation below 13.0%. Ten blind samples of chicken muscle were analysed simultaneously by ELISA and liquid chromatography-tandem mass spectrometry, and a good correlation between the methods was observed. The results indicated that the high affinity antibody could be applied for the simple and fast detection of RBV in multi-food matrices.     

海洋微藻的简易培养方法

本介绍了海洋微藻培养的设备，常用藻种及其来源，海洋微藻的一般培养方法。     

藤茶中二氢杨梅素的绿色提取纯化方法研究

主要研究了二氢杨梅素的新型绿色提取纯化方法。结果表明:采用热水提取法,通过单因素分析和正交实验对提取工艺条件进行了优化。采用活性炭脱色、多次重结晶的纯化方法获得了纯度在98%以上的二氢杨梅素。     

Some simple methods for the purification of pectic enzymes from Aspergillus usamii

In the course of an investigation of the enzymatic degradation of pectic substances by Aspergillus usamii Sakaguchi, we found that the fungus produced extracellular pectic enzymes in significant amounts, and the enzymes were able to macerate various kinds of pectic substances.²² The present paper reports and discusses the results obtained with several analytical techniques in the purification of a crude mixture of extracellular pectic enzymes produced by Aspergillus usamii Sakaguchi. Comparing chromatography on DEAE-cellulose with DEAE-Sephadex A-50, the first gave optimal enzyme recovery and good separation, whereas the second demonstrated good active protein resolution but low recovery (with the exception of the 93% recovery of pectintranseliminase (PTE)). 2-Ethoxy-6, 9-diamineacridine lactate (rivanol) was capable of separating the enzymes with good PTE and polymethylgalacturonase (PMG) recoveries. Acrylamide gel electrophoresis on an analytical scale separated the crude mixture into seven protein bands: the first and seventh were identified as pectinesterase (PE) and polygalacturonase (PG) respectively. The most important result of preparative electrophoresis was the isolation of PE. The question of separating PG from PMG is discussed.     

抗生素在鸡蛋及鸡体组织中的代谢研究

目的 探究蛋鸡养殖业中广泛使用且在市场鸡蛋中检出频率较高的3种抗生素：氟苯尼考(florfenicol, FF)、恩诺沙星(enrofloxacin, ENR)、多西环素(doxycycline, DOX)在鸡蛋及鸡体组织中的代谢情况。方法 试验选取健康的103日龄育成鸡和300日龄产蛋鸡各105只,均分成7组,分别为FF低、FF高、ENR低、ENR高、DOX低、DOX高以及对照组。以肌肉注射的方式连续给药5 d,“低”代表说明书正常用量,“高”代表正常用量的一倍,对鸡只接受抗生素后一段时间内所产鸡蛋及鸡体组织中药物残留情况进行检测分析。结果 103日龄育成鸡使用抗生素后,至鸡只130日龄时所产鸡蛋中能检测到氟苯尼考残留,150日龄时所产鸡蛋中能检测到恩诺沙星和多西环素残留,3种抗生素还造成蛋鸡肝脏组织表面不同程度的出血和坏死;300日龄产蛋鸡注射抗生素后,氟苯尼考在蛋清、蛋黄中消除的时间分别为10 d、12 d。恩诺沙星在蛋清、蛋黄中消除的时间均为9 d。多西环素在蛋清、蛋黄中消除的时间均为25 d。结论 蛋鸡育成后期使用抗生素会对初产鸡蛋及鸡的肝脏组织造成一定影响,针对我国市场动物源性食品中频繁检出抗生素等问题,建议关注蛋鸡后备期抗生素的使用,不断强化市场监督机制和准入门槛,保障鸡蛋安全,维护人体健康。     

虫胶涂膜对鸡蛋保鲜效果的研究

以新鲜鸡蛋为原料,虫胶为保鲜膜材料,在温度为(20±2)℃,相对湿度为50%±10%的条件下,研究不同浓度的虫胶涂膜对鸡蛋的失重率、哈夫单位、蛋黄指数、蛋清pH、蛋黄pH的影响。结果表明:经过21d的储存后,虫胶涂膜处理后的鸡蛋比未处理鸡蛋保鲜效果好,其中以3.00%的虫胶涂膜效果最佳,其失重率为3.04%,哈夫单位为69.03,蛋黄指数为0.31,蛋清pH为9.45,蛋黄pH为7.07。      

Investigation of iodine bioavailability from chicken eggs versus iodized kitchen salt with in vitro method

The goal of the presented studies was to investigate speciation and bioavailability of iodine from chicken eggs versus iodized kitchen salt with an in vitro method. Determination of iodine total content in chicken eggs and iodized kitchen salt was carried out by inductively coupled plasma mass spectrometry (ICP MS). The majority of iodine was accumulated in the yolk—the concentration was even 37 times higher than in white. Chicken eggs were treated with buffer (Tris HCl pH = 7.5) and enzymatic extraction media and analyzed by size exclusion chromatography hyphenated with inductively coupled plasma mass spectrometry (SEC ICP MS). The enzymatic extraction being an in vitro bioavailability assessment method was based on two-stage digestion model simulating gastric (pepsin digestion) and intestinal (pancreatin digestion) juices. Speciation analyses along with bioavailability studies presented iodide as the major form in chicken eggs. The bioavailability was established as 33% from white and 10% from yolk and decreased with longer time of boiling. It allows to suggest that the majority of iodine remains in forms bound to non-digestible coagulated and water-insoluble proteins.     

Levels of polychlorinated bifenilis and organochlorine in pesticides in chicken eggs from different Russian regions

Chicken eggs are recognized as a useful matrix for international comparison of accumulation levels of persistent organic pollutants (POPs) in foodstuffs. The paper contains results of detection of 17 congeners of PCB, hexachlorobenzene, hexachlorocyclohexane, DDT and its metabolites in chicken eggs, collected near the former PCB-containing producing plant (Novomoskovsk), the plant earlier produced organochlorine pesticides and hexachlorobenzene (Chapaevsk) and from several areas of the Saratov region. Comparison of obtained results with data from IPEN international study has shown that PCBs levels in chicken eggs from the town of Novomoskovsk and from Chapaevsk local farms is significantly higher than for the most polluted territories in different countries of the world. Chicken eggs' pollution by DDT and HCCH is less expressed than by PCBs. Analysis of these matters' content in chicken egg samples, collected in five poultry farms in different regions of Russia has not revealed a remarkable level of chlorinated pesticide pollution.     

Oxytetracycline residues in retail chicken eggs in Ibadan,Nigeria

Oxytetracycline residues in chicken eggs from five markets within Ibadan metropolis were determined by high-performance liquid chromatography following solid-phase extraction. Recovery of oxytetracycline was 80.5%–87.8%, whereas 75.2% of the samples contained detectable oxytetracycline with an overall mean residue concentration of 479.0?µg?kg^?1. Residue concentrations from Iwo Road, Apata, Challenge, Ojoo and Bodija markets were 421, 460, 468, 568 and 476?µg?kg^?1, respectively. Eggs from Ojoo market had the highest levels, whereas 68.8% of the samples contained residues above the Codex Alimentarius Commission maximum residue limit. The results are of public health interest as they indicate that a greater proportion of eggs being consumed in Ibadan could contain residues above the maximum residue limit, for which unregulated access and indiscriminate use of antibiotics by poultry farmers could be responsible. National surveillance of eggs and other animal products for antibiotic residue and appropriate regulation of antibiotic is recommended to ensure food safety for consumers.     

鸡蛋期货价格与毛鸡价格的相关性分析

期货套期保值交易功能是企业规避价格波动风险的一个有力工具。利用简单的Excel数据分析功能对鸡蛋期货价格和毛鸡价格进行相关性分析;探讨毛鸡养殖、屠宰企业进行套期保值交易,对冲风险的可行性。     

天然植物中原花青素提取和纯化方法研究进展

原花青素属于多酚类化合物,与植物多糖、生物黄酮等活性物质一样广泛存在于各种植物之中。近年来针对植物中原花青素活性功能研究逐渐增多,研究发现其具有很强的生物活性,如清除自由基、抗癌、抗突变、预防和治疗心血管疾病等,且安全无毒。现在原花青素已广泛应用于临床医学、化妆品、保健食品和食品工业等领域。目前天然植物中原花青素的提取和纯化研究已经成为热门课题,本文主要总结归纳了原花青素溶剂浸提法、超声辅助提取法、微波辅助提取法、离子液体提取法、超临界流体提取法、酶提取法6种提取工艺和大孔树脂吸附法、高速逆流色谱法、膜过滤法、凝胶色谱法4种纯化方法,简要介绍了其基本原理,同时分析了各方法的优缺点,以期为以后的相关科研工作提供一定的参考。     

树莓超氧化物歧化酶的提纯方法比较

利用凝胶层析初步纯化树莓SOD,纯化条件:柱体1.6cm×60cm,磷酸盐缓冲液pH7.8、2.5mmol/L,流速O.3mL/min,每管收集3mL.经过SephadexG-100层析分离纯化,得到三种SOD同工酶.分别通过金属螯合亲和层析和DEAE-52层析进一步对树莓SOD纯化,并比较两者纯化效果.金属螯合亲和层析纯化得到SOD的回收率和纯化倍数均高于DEAE-52层析,因此金属螯合亲和层析更有利于SOD的进一步纯化.     

Kinetics of semicarbazide and nitrofurazone in chicken eggs and egg powders

The accumulation, depletion and partitioning of semicarbazide (SEM) and its parent compound nitrofurazone (NFZ) in eggs were studied using hens fed NFZ at therapeutic and sub-therapeutic levels. Dietary NFZ correlated strongly with NFZ and total SEM in eggs, while 28% of observed SEM was present in the form of parent NFZ. Depletion half-life in eggs was 2.4 days for SEM and 1.1 days for NFZ. NFZ accumulated preferentially in yolk (57–63%) as opposed to albumen, while 71–80% of SEM was found in yolk. In whole egg, 29% of SEM was present as tissue-bound residues compared with 80% in breast muscle. Whilst NFZ and SEM were partly degraded by pasteurization and spray drying, sufficient NFZ remained to suggest it might be detectable in egg powders when SEM is observed at low µg kg^?1 concentrations. NFZ was detectable in whole eggs during ingestion of only 0.1% of the therapeutic NFZ dose, making detection of intact NFZ in eggs a feasible means to prove conclusively the administration of this banned compound.     

Ovomucin content and composition in chicken eggs with different interior quality

Egg albumen ovomucin distribution and composition were studied in fresh eggs with relatively low or high internal quality as indicated by Haugh unit (HU) values. Egg HU had been altered as a result of genetic selection (mean all eggs: 87 vs 73 HU) or by feeding vanadium (V) to hens (mean all eggs: 91 vs 80 HU). In both altered HU conditions, eggs with low HU values yielded significantly less water-insoluble ovomucin from the thick albumen than eggs with high HU values, whereas the yield of ovomucin from thin albumen did not differ. The amount of ovomucin differed between eggs with high or low HU values as a result of feeding V, but the composition of ovomucin from the thick albumen was not affected. This was confirmed by SDS-PAGE gels, carbohydrate contents, and amino acid contents. When HU values were different as a result of genetics, ovomucin was affected differently. The total amount of ovomucin isolated from the thick albumen of the eggs with high HU was much higher than the amount isolated from the low HU thick albumen. The composition of the ovomucin was also different. SDS-PAGE gels showed a greater proportion of the highly glycosylated β-subunit in the ovomucin from the low HU eggs. Carbohydrate analyses showed higher concentrations of sialic acids, hexoses and hexosamines in the ovomucin from the low HU eggs. The only difference between the ovomucins in the amino acid content was that isoleucine was slightly higher in the high HU ovomucin. © 1999 Society of Chemical Industry     

Electron spin resonance technique identification and dosimetry of irradiated chicken eggs

The electron spin resonance (ESR) technique was tested for the identification and dosimetry of irradiated chicken eggs by ESR measurements of the shell. the spectrum of powdered egg shells was interpreted as the superposition of three signals due to long-lived CO₃, ^- CO₃^3- and CO₂^- ions of the calcium carbonate matrix. Taking the amplitude of the central peak as the dose-dependent parameter, a linear dose-effect relationship was obtained up to 10kGy. the results obtained suggest the use of EPR for qualitative and quantitative analysis of irradiated fresh eggs.