Recovery of eggs of two parasitic nematodes, Ascaris sp. and Trichuris sp.: Interlaboratory study

An interlaboratory study was conducted to determine the effectiveness of the Nacconol ether centrifugation method for recovering parasitic nematode eggs from 3 contaminated products: a crop (cabbage), a sludge fertilizer (Milorganite), and a sewage effluent (Minneapolis). Six replicate samples for each of the 3 products were seeded with eggs at 3 different levels: 200 Ascaris suis and 8 Trichuris muris; 15 A.suis and 15 T.muris; 8 A.suis and 180 T.muris. Recovery was low for all samples except sewage effluent, in which recoveries greater than 100% in 2 samples resulted from the misidentification of arthropod eggs as Ascaris sp. The average mean percent recovery for the other samples was 22.53. Repeatability for replicate samples and reproducibility of results by individual laboratories were poor, and the method is not recommended for quantitative estimates of nematode egg contamination of foods and food-contact materials. However, the Nacconol ether centrifugation method can be used as an all-or-none test. (Only 13% of 1146 counts were falsely negative.) Of 69 samples, only 4 were falsely negative for A.suis eggs and only 1 was falsely negative for T.muris eggs in counts of 6 replicates.     

Determination of the hop-derived phytoestrogen, 8-prenylnaringenin, in beer by gas chromatography/mass spectrometry

A method was developed to determine 8-prenylnaringenin, a novel hop-derived phytoestrogen, in beer. Matrix purification involved solid-phase extraction on octadecyl silica followed by liquid/liquid extraction on a ChemElut 1010 column connected to a Florisil adsorption/desorption cartridge. 8-Prenylnaringenin was eluted from the tandem columns using a 1:1 mixture of diethyl ether and ethyl acetate and subsequently determined as tris(trimethylsilyl) ether by GC/MS-SIM. The recovery of 8-prenylnaringenin in beer samples was between 61.1 +/- 6.6 and 82.2 +/- 8.8% for levels of 37 and 92.5 microg L(-1), respectively, and the detection limit was approximately 5 microg L(-1). Although most beers do not contain 8-prenylnaringenin in detectable quantities, the highest concentration found was 19.8 microg L(-1). The concentration of 8-prenylnaringenin in beers and, possibly, its absence depend on the selection of particular hop varieties, the hopping rate, or the type of hop product used in brewing. The efficiency of transfer of 8-prenylnaringenin from hops to beer is between 10 and 20%.     

Furfuryl ethyl ether: important aging flavor and a new marker for the storage conditions of beer

Recently, it was reported that furfuryl ethyl ether is an important flavor compound indicative of beer storage and aging conditions. A study of the reaction mechanism indicates that furfuryl ethyl ether is most likely formed by protonation of furfuryl alcohol or furfuryl acetate followed by S(N)2-substitution of the leaving group by the nucleophilic ethanol. For the reaction in beer, a pseudo-first-order reaction kinetics was derived. A close correlation was found between the values predicted by the kinetic model and the actual furfuryl ethyl ether concentration evolution during storage of beer. Furthermore, 10 commercial beers of different types, aged during 4 years in natural conditions, were analyzed, and it was found that the furfuryl ethyl ether flavor threshold was largely exceeded in each type of beer. In these natural aging conditions, lower pH, darker color, and higher alcohol content were factors that enhanced furfuryl ethyl ether formation. On the other hand, sulfite clearly reduced furfuryl ethyl ether formation. All results show that the furfuryl ethyl ether concentration is an excellent time-temperature integrator for beer storage.     

Gas-liquid chromatographic determination of nifursol in frozen turkey tissues to ten parts per billion.

Nifursol (3,5-dinitrosalicylic acid (5-nitrofurfurylidene) hydrazide) is extracted into ethyl acetate from 10 g tissue in the presence of sodium sulfate. Tissue interferences are removed from the tissue extract by washing with petroleum ether after the extract has been transferred into an aqueous solution by evaporation of ethyl acetate. The drug is hydrolyzed under acid conditions to form 5-nitro-2-furaldehyde (5NF). After partition of 5NF from the aqueous phase into benzene the extract is further cleaned up on a Florisil column. The 5NF is eluted from the Florisil column with benzeneethyl acetate. Electron capture gas-liquid chromatography of a 10 mul injection of the concentrated column eluate is the determinative step. Quantitation is accomplished by comparison of the peak height of the sample to the peak height of the standard which is carried through the method simultaneously. Studies of method performance on turkey muscle, liver, kidney, and skin tissues fortified to contain 10 ppb nifursol show a recovery range of 87.4-95.0% and a coefficent of variation range of 5.7-11.2%.     

Volatile components of Loureira, Dona Branca, and Treixadura wines.

White wines experimentally produced from the white grape varieties Loureira, Dona Branca, and Treixadura have been analyzed over four consecutive harvests. The contents of monoterpenes, volatile phenols, alcohols, sulfur components, acetates, fatty acids, and ethyl esters were determined by gas chromatography (FID) and gas chromatography-mass spectrometry. The mean values from four vintages confirmed that these wines have characteristic profiles. Loureira wines are characterized by a high content of free terpenes, 1-hexanol, ethyl acetate, and fatty acids. Dona Branca wines present the highest concentrations of methanol and sulfur constituents, and the lowest concentrations of higher alcohols, acetates, diethyl succinate, and ethyl esters. The levels of monoterpenes in Treixadura wines are very low, but they have the highest concentrations of volatile phenols, principally due to the vanillin, diethyl succinate, ethyl lactate, and ethyl esters. These results were confirmed by principal component and linear discriminant analysis, which show a clear differentiation among these wines as a function of the varietal origin.     

Potential of Trichoderma spp. as consistent plant growth stimulators

In a series of repeated trials, six Trichoderma spp. strains, applied as a dried powder from a liquid fermentation in molasses/yeast medium, proved to be consistent at promoting the growth of lettuce (Latuca sativa L.) seedlings grown in a peat-sand potting compost in the glasshouse. Strains WT, 92, 20, and 75 at 0.75% or 1% w:w concentrations increased shoot dry weight by up to 26%, although WT did inhibit germination. For example, after 4 days only 13% of seeds sown in WT 1% w:w treated compost had germinated, whereas in other treatments germination was consistently greater than 32%. WT increased shoot fresh and dry weights by 14.3 g and 0.6 g per pot, respectively, without affecting the root dry weights, to give concomitant increases in shoot: root ratios of fresh and dry weight. The potential use of these Trichoderma spp. strains for plant growth promotion is discussed.     

Matrix solid phase dispersion (MSPD) isolation and liquid chromatographic determination of furazolidone in pork muscle tissue

A method for the isolation and liquid chromatographic (LC) determination of furazolidone in pork muscle tissue is presented. Blank or furazolidone-fortified pork muscle tissue samples (0.5 g) were blended with octadecylsilyl (C18, 18% load, endcapped, 2 g) derivatized silica. A column made from C18/pork matrix was first washed with hexane (8 mL), followed by elution of furazolidone with ethyl acetate. The ethyl acetate extract was then passed through an activated alumina column. The eluate contained furazolidone that was free from interfering compounds when analyzed by LC with UV detection (photodiode array, 365 nm). Detector response with increasing concentrations of furazolidone isolated from fortified samples was linear (r = 0.998 +/- 0.002) with an average percentage recovery of 89.5 +/- 8.1% for the concentration range (7.8-250 ng/g) examined and resulted in a minimum detectable limit of 390 pg on column, and a detector response of more than 5 times baseline noise. The inter-assay variability was 9.9 +/- 5.4% with an intra-assay variability of 1.5%.     

Gas chromatographic quantification of major volatile compounds and polyols in wine by direct injection

Methanol, propanol, isobutanol, isoamyl alcohol, 2-phenylethanol, acetaldehyde, 1,1-diethoxyethane, acetoin, ethyl acetate, ethyl lactate, and ethyl succinate and the polyols 2,3-butanediol (levo and meso forms) and glycerol were quantified by direct injection of wine samples. Linear responses over the usual concentration ranges for these compounds and r2 values from 0.9932 to 0.9998 were obtained. The confidence limits for the mean values ranged from 2.34% for diethyl succinate to 8.52% for 1,1-diethoxyethane, both at a probability level of 0.05. Relative errors ranged from 8 to 10% for the polyols and 1,1-diethoxyethane and were all less than 5% for alcohols and acetaldehyde. The proposed method is useful with a view to identifying relationships between alcoholic fermentation byproducts and controlling biological or chemical aging in wines.     

Determination of free and total phenolic acids in plant-derived foods by HPLC with diode-array detection

A high-performance liquid chromatographic (HPLC) method with diode-array detection (DAD) was used to identify and quantify free and total phenolic acids (m-hydroxybenzoic acid, p-hydroxybenzoic acid, protocatechuic acid, gallic acid, vanillic acid, syringic acid, o-coumaric acid, m-coumaric acid, p-coumaric acid, caffeic acid, ferulic acid, sinapic acid, chlorogenic acid, and ellagic acid) in plant foods. Free phenolic acids were extracted with a mixture of methanol and 10% acetic acid. Bound phenolic acids were liberated using first alkaline and then acid hydrolysis followed by extraction with diethyl ether/ethyl acetate (1:1). All fractions were quantified separately by HPLC. After HPLC quantification, results of alkali and acid hydrolysates were calculated to represent total phenolic acids. Ellagic acid was quantified separately after long (20 h) acid hydrolysis. The methods developed were effective for the determination of phenolic acids in plant foods. DAD response was linear for all phenolic acids within the ranges evaluated, with correlation coefficients exceeding 0.999. Coefficients of variation for 4-8 sample replicates were consistently below 10%. Recovery tests of phenolic acids were performed for every hydrolysis condition using several samples. Recoveries were generally good (mean >90%) with the exceptions of gallic acid and, in some cases, caffeic acid samples.     

Determination of aflatoxicol and aflatoxins B1 and M1 in eggs

Procedures from 2 methods, one for aflatoxins B1 and M1 in eggs and one for aflatoxicol in milk, blood, and liver, have been combined to determine the 3 toxins in eggs. The sample is blended with sodium chloride-saturated water and this mixture is then blended with acetone. After separation from the solid residue, the aqueous acetone extract is defatted with petroleum ether. The toxins are next partitioned into chloroform and separated from interferences on a silica gel column. Aflatoxicol is determined by fluorescence measurement after separation on a C18 reverse phase liquid chromatographic column, and aflatoxins B1 and M1 are determined by fluorescence densitometry after separation on a silica gel thin layer chromatographic plate. In a recovery study with eggs, mean recoveries of aflatoxicol added at levels of 0.1, 0.05, and 0.025 ng/g were 87, 77, and 78%, respectively. Mean recoveries of aflatoxins B1 and M1 added at a level of 0.1 ng/g were 75 and 87%, respectively, and at an added level of 0.05 ng/g were 86 and 75%. The within-laboratory precision (repeatability) ranged from 2 to 13%.     

Simultaneous liquid chromatographic screening of five coccidiostats in chicken liver

A reverse-phase liquid chromatographic (LC) method is described for simultaneously determining 5 coccidiostats--aklomide, dinsed, ethopabate, nitromide, and zoalene in chicken liver. The method entails blender extraction of 10 g liver with ethyl acetate, column chromatography through Sephadex LH-20 and neutral alumina, and LC analysis on a C18 column with UV detection at 260 nm. The drugs were eluted from Sephadex with methanol-benzene (10 + 90), from alumina with methanol-dichloromethane (10 + 90), and from C18 with acetonitrile-water (linear gradient: 25% acetonitrile for 10 min, increasing to 55% over 15 min; flow rate 1 mL/min). Liquid chromatography was completed in 40 min and calculations were based on peak height measurements. Average recoveries of the coccidiostats from fortified liver ranged from 72 to 97%, except for dinsed, which showed a relatively constant average recovery of 57%. The detection limit for the standards was 2.5 ng on column. Levels as low as 50 ng/g were detected in fortified liver samples.     

Extraction and identification of natural antioxidant from Sideritis euboea (mountain tea)

The dried aerial parts of the mountain tea Sideritis euboea were extracted using n-hexane, methanol, diethyl ether, ethyl acetate, and n-butanol. The residues were tested for their antioxidant activity on sunflower oil at 50 degrees C under UV light. The oxidation of the sunflower oil was measured using PV, absorbance E(1%)1 cm, and malondialdehyde by high-performance liquid chromatography (HPLC). The butanol extract showed the highest antioxidant activity and was further fractionated by silica and cellulose column chromatography and finally by HPLC. The activity of the final fraction on a range of vegetable oils was compared to that of common used antioxidants (BHT, alpha-tocopherol) using DPPH*, the Rancimat method, and the Schaal oven test. At a level of 400 ppm, the extracted kaempherol showed the highest antioxidant activity among all antioxidants tested. The final fraction was identified (using UV, 1H NMR, 13C NMR, mass spectroscopy, and melting point) as 3,5,7,4'-tetrahydroxy flavone (kaempherol).     

Rapid liquid chromatographic determination of patulin in apple juice

A rapid method is described for the quantitative determination of patulin in apple juice. The mycotoxin is extracted from the sample with ethyl acetate and the extract is cleaned up by extraction with a sodium carbonate solution. Patulin is determined by reverse phase liquid chromatography using a muBondapak C18 column and a 254 nm ultraviolet detector. The lower detection limit in patulin standard solution is 0.32 ng and recovery is greater than 75%.     

生活污泥对白菜供磷和土壤磷状况的影响

采用好气培养和盆栽试验以探明污泥磷的肥效,降低污泥施用导致的土壤磷累积引起的环境风险。结果表明,单施污泥土壤有效磷含量和白菜吸磷量均显著低于施用磷酸一铵和鸡粪处理;施用污泥后有利于增加白菜生长后期土壤磷酸酶的活性和土壤Olsen-P含量。在白菜等产量条件下,单施污泥处理土壤中Olsen-P残留量显著高于污泥与化肥混施处理;在P2O5施用量为902~70 kg/hm2时,污泥堆肥磷的肥效为磷酸一铵的25%左右。     

Liquid chromatographic determination of rotenone in fish, crayfish, mussels, and sediments

An analytical procedure is described for determining residues of rotenone in fish muscle, fish offal, crayfish, freshwater mussels, and bottom sediments. Tissue samples were extracted with ethyl ether and extracts were cleaned up by gel permeation chromatography and silica gel chromatography. Sediment samples were extracted with methanol, acidified, partitioned into hexane, and cleaned up on a silica gel column. Rotenone residues were quantitated by liquid chromatography, using ultraviolet (295 nm) detection. Recoveries from sediment samples fortified with rotenone at 0.3 microgram/g were 80.8%, whereas recoveries from tissue samples fortified with 0.1 microgram/g ranged from 87.7 to 96.8%. Samples fortified with 0.3 microgram/g and stored at -10 degrees C for 6 months before analysis had recoveries ranging from 83.2 to 90.5%. Limits of detection were 0.025 microgram/g for sediments and 0.005 microgram/g for tissue samples.     

Leaf epicuticular wax as a factor of antixenotic resistance of cabbage to cabbage flea beetles and cabbage stink bugs attack

The aim of present research was to establish the role of epicuticular wax content in eight cabbage genotypes (four white hybrids and one red hybrid, two red varieties and one white variety) in the context of its natural resistance to attack cabbage flea beetles (Phyllotreta spp.) and cabbage stink bugs (Eurydema spp.), which are among the most important cabbage pests in southern Europe. For this reason and for the purpose of diminishing the use of synthetic insecticides against the cabbage pests the field experiments in 2006 and 2008 were conducted. We found out that individual cabbage genotypes – they had different epicuticular wax content – differ in regard to their susceptibility to attacks by the studied groups of harmful insect pests. The highest susceptibility to attacks by Phyllotreta spp. was confirmed for the hybrid ‘Cheers F1’, in the first year (1.68 ± 0.05), as well as in the second year of the experiment (2.87 ± 0.13). Cabbage stink bugs in both years of the experiment caused the highest extent of injuries on the hybrids ‘Destiny F1’, ‘Cheers F1’, and ‘Vestri F1’. In both years we found higher epicuticular wax content in red cabbage genotypes. In almost all studied genotypes we found a pronounced negative correlation between the content of epicuticular wax and the extent of injuries done by both groups of harmful pests. We have established that epicuticular wax is an important factor of cabbage's antixenotic resistance to attacks by cabbage flea beetles and cabbage stink bugs, and that the cabbage genotypes with higher content of this substance are consequently more suitable for environmentally acceptable manners of cabbage production.     

商陆不同极性、根和茎提取物的抑菌性能分析

为探究商陆不同极性、部位提取物的抑菌性能,本实验分别从商陆根和茎中提取石油醚相、乙酸乙酯相、正丁醇相和水相4种不同极性的提取物,再采用滤纸片法测量提取物对大肠杆菌（Escherichia coli）、金黄色葡萄球菌（Staphyloccocus aureus）、巨大芽孢杆菌（Bacillus megaterium）和副溶血弧菌（Vibrio parahaemolyt-icus）4种细菌的抑制性能。结果表明,部分商陆的提取物有一定的抑菌活性,如根正丁醇相对巨大芽孢杆菌和副溶血弧菌,茎水相对副溶血弧菌的抑菌圈在10mm以上,但总体上商陆的提取物的抑菌性能远不及头孢氨苄好。实验还发现商陆抑菌活性最强的物质大都存在于根中,且抑菌活性最强的物质大都存在于水和正丁醇这种极性较高的溶剂的提取物中,不同提取物对不同细菌的抑菌活性情况不一致。因此本研究结果可以为商陆提取物抑菌性能的进一步探索提供参考。     

Xanthophylls in commercial egg yolks: quantification and identification by HPLC and LC-(APCI)MS using a C30 phase

The xanthophylls lutein and zeaxanthin have attracted a lot of interest since it was presumed that an increased nutritional uptake may prevent adult macula degeneration (AMD). Although egg yolks serve as an important dietary source of lutein and zeaxanthin, data on xanthophyll concentrations in commercial egg yolks are not available. Thus, an high-performance liquid chromatography-diode array detector (HPLC-DAD) method was developed allowing for simultaneous separation of eight xanthophylls used to fortify poultry feed. Peak identification was carried out by liquid chromatography-atmospheric pressure chemical ionization mass spectrometry [LC-(APCI)MS]. Egg yolks of four types of husbandry (seven batches each) were examined. Lutein and zeaxanthin were the predominant xanthophylls in egg yolks produced in accordance with ecological husbandry (class 0) because the concentrations of these xanthophylls ranged from 1274 to 2478 microg/100 g and from 775 to 1288 microg/100 g, respectively. Analysis of variance (ANOVA) proved that both mean lutein and mean zeaxanthin concentrations of eggs from class 0 were statistically discriminable from mean lutein and zeaxanthin concentrations from eggs of all other classes (P < 0.01). Mean concentrations of synthetic xanthophylls in eggs of classes 1 (free range), 2 (barn), and 3 (cage) were as follows: canthaxanthin, 707 +/- 284 microg/100 g; beta-apo-8'-carotenoic acid ethyl ester, 639 +/- 391 microg/100 g; and citranaxanthin, 560 +/- 231 microg/100 g. Experiments with boiled eggs proved that beta-apo-8'-carotenoic acid ethyl ester was the xanthophyll with the highest stability, whereas lutein was degraded to the largest extent (loss of 19%). Detailed knowledge about the xanthophyll amounts in eggs is indispensable to calculate the human uptake.     

Liquid chromatographic method for determining the macrolide antibiotic sedecamycin and its major metabolites in swine plasma and tissues

A liquid chromatographic (LC) method was developed to determine sedecamycin, a 17-membered macrolide antibiotic used for treating swine dysentery, and its major metabolites (lankacidin C, lankacidinol A, and lankacidinol) in swine plasma and tissues. Plasma is directly extracted with ethyl acetate and analyzed by liquid chromatography without purification. Tissues are homogenized in a phosphate buffer containing sodium chloride, and then extracted with ethyl acetate. The extracts are subjected to silica gel-Florisil, double-layered column chromatography to remove endogenous interfering substances. The LC determination uses silica gel and ODS-silica as a stationary phase. The detection limits for sedecamycin and its metabolites were less than or equal to 0.05 ppm, and average recoveries and coefficients of variation (0.2-1 ppm range) were greater than 75% and less than 10%, respectively.     

Odor-active headspace components in fermented red rice in the presence of a monascus species

Headspace components from rice and agar with (experimental) and without (control) inoculation with a Monascus spp. were investigated. Kinetics studies were carried out. Using rice as a substrate, 10 and 19 compounds were found for the control and the experimental groups, respectively, at day 14. Experimental group compounds were composed mainly of alcohols, ketones, and esters, whereas control group compounds were composed of aldehydes and ketones. With agar as a substrate, only five and three components were found in the control and experimental groups, respectively. Five alcohols, four esters, two ketones, and one furan with odor activity values (OAV) >1 dominated the overall flavor of the product. With liquid inoculation, the first six components with high OAVs were in the following order: 3-methyl-1-butanol (17) > ethanol (14) > ethyl acetate (10) > 2-methyl-1-propanol (15) > ethyl butanoate (11) > 3-methylbutyl acetate (13). Kinetic studies showed that most compounds reached their maximum concentrations at 10-12 days. Many compounds identified in the model red rice were reported in commercial red sufus, and several appeared to contribute solely by red rice.