Fenhexamid residues in grapes and wine

The behaviour of the fungicide, fenhexamid, on grapes, and during wine-making, as well as its effect on the microflora of alcoholic and malolactic fermentation has been studied. After treatment, the residue on grapes decreased rapidly to one-third of the initial level after the first week, while it remained constant during the following two weeks. At harvest, in the wine obtained by vinification without skins, the fungicide residue decreased on average by 49% , while in the wine obtained by vinification with skins, the decrease was on average 62% . The presence of this fungicide on grapes and in the wine did not affect alcoholic and malolactic fermentation, nor did fermentation cause any degradation of the fungicide. A simple and rapid gas chromatograhic method (GC-NPD) for the determination of fenhexamid residues in grapes, must and wine is described.     

Determination of pesticide residues in wine using gas chromatography with nitrogen-phosphorus and electron capture detection

A multiresidue method employing an extraction step with ethyl acetate followed by clean-up using an Isolute silica column and determination using gas chromatography with nitrogen-phosphorus and electron capture detection was validated for a wide range of pesticide residues in white and red wine. Recoveries between 70 and 110% and relative standard deviations below 20% were obtained for nearly all target analytes using matrix-matched standards. Limits of detection based on three times the signal-to-noise ratio were in the range 0.002-0.01 mg l^-1 for most compounds. The chromatograms were generally free of interference peaks resulting from co-extractives, although a few were noted for red wine with nitrogen-phosphorus detection. Ninety-two wine samples collected in Greece and Yugoslavia during 2 consecutive years were screened for residues of 84 pesticides, 71% of which were registered for use on vines in one or both countries. A total of 20% of the samples were obtained from field trials, and of these, one Greek wine contained iprodione 0.3 mg l^-1 and six Yugoslavian wines, for which vinclozolin had been added to the must as part of a different study, contained residues of this pesticide. No residues were detected in any of the other samples.     

Potential ochratoxin A producers from wine grapes in Argentina and Brazil

The aim was to identify the normal mycoflora in wine grapes from Argentina and Brazil. We collected 50 grapes samples from Malbec and Chardonnay varieties in each country during the 1997-98 harvest. Yeasts were a major component of the fungal population, and the most frequent genera of filamentous fungi isolated were: Aspergillus, Penicillium and Botrytis. Other genera identified (in decreasing order) were: Phythophthora, Moniliella, Alternaria and Cladosporium. From grapes, the mean frequency of filamentous fungi ranged from 1.3 × 10⁴ to 5.4 × 10⁶ CFUg^-1. We isolated 48 Aspergillus niger strains from Argentinian grape, of which eight could produce ochratoxin A. Sixteen of 53 A. niger strains from Brazilian grapes produced ochratoxin A. The results indicate that similar mycobiota were isolated from Argentinian and Brazilian wine grapes and there could be ochratoxin A production in this substrate.     

Pesticide residues in the Canadian Market Basket Survey 1992 to 1996

Market basket food samples from six Canadian cities collected from 1992 to 1996 were analysed for pesticide residues. One hundred and thirty-six composites were prepared for each city, representing 99% of the Canadian diet. Residues were found most frequently in peanut butter and butter. DDE, malathion and captan occurred most frequently, while the fungicides chlorothalonil, dicloran and captan were present in the highest concentrations. Processed commodities contained fewer residues and at lower concentrations than the raw products. No residues were detected in either milk or soy-based infant formula. Of the infant foods sampled, fruit contained both the greatest number and highest concentrations of pesticides.     

Residues of cypermethrin in field-treated grapes and raisins produced after various treatments

Residues of the synthetic pyrethroid insecticide cypermethrin in fresh grapes of cv. Thomson Seedless and in raisins were studied. The commercial formulation Cymbush® 10% EC was applied according to the label onto the typical seedless variety and on a seed-producing clone. Samples were collected at time zero and at 15 or 21 days post-application. The raisins were produced either by submersion for 3 min in an aqueous solution of 3% potassium carbonate and 1% ethyl oleate, and dried for 15 days under direct sunlight or were dried without chemical processing. A gas chromatographic method was used for the analysis of residues. The residues in the grapes at the recommended preharvest interval (15 days) ranged from 0.23 to 0.41 mg kg -1 , whereas those in raisins ranged from 0.25 to 0.46 mg kg -1 .     

食品中残留农药检测技术的新进展

对食品中残留农药检测技术其新进展进行了综述。样品前处理中,固相萃取、超临界流体萃取、基质固相分散萃取得到了迅速发展和广泛应用。毛细管气相色谱、超临界流体色谱、液相色谱---质谱联用技术、酶免疫分析等已开始应用于食品的残留家药检测中。直接光谱技术和生物传感器的应用潜力很大。对食品中残留农药检测技术的发展进行了展望。     

Effect of postharvest dehydration on the composition of pinot noir grapes (Vitis vinifera L.) and wine

This study was conducted in order to improve our understanding of how phenolics and aroma compounds change in wine grapes during postharvest dehydration. Pinot noir grapes grown in the Willamette Valley of Oregon were harvested at 22.0 and 24.0 °Brix. Grapes harvested at 22.0 °Brix were divided into three equal lots with one lot immediately used for wine production, and the remaining two lots placed inside an air tunnel with an air speed of 1.0–1.8 m s⁻¹, 38% relative humidity and a temperature of 22 °C. The soluble solids content and weight loss were measured daily and wines were made from grapes when they reached 24.8 and 26.7 °Brix. The soluble solids of grapes increased about 1 °Brix per day; therefore, on the third and fourth day the berries reached the desired concentration; weight loss was 14 and 16%, respectively. Results from berry phenolic analysis indicated that per berry anthocyanin amount remained unchanged during dehydration. The composition of proanthocyanidins isolated from berries changed during dehydration. Volatile compounds in wines made from dehydrated grapes contained more terpenes and norisoprenoids (β-ionone, β-damascenone) when compared to wine made from the original fruit. Wines made from increasingly dehydrated grapes tended to resemble the composition and flavour profile of wines made from grapes left on the vine (i.e. with extended ripening). The results of this study suggest that postharvest flavour changes consistent with changes during fruit ripening can occur in grapes when harvested early and allowed to dehydrate under controlled conditions prior to fermentation.     

Residue variability and sampling practical problems and consequences for residues monitoring

Data generated in the UK have indicated that pesticide residue levels can be highly variable between the individual fruit or vegetables from the same crop or lot in trade. Statistical experiments with these data showed that residues in composite samples, taken according to Codex recommendations, are unlikely to differ by more than a factor of 3-4 from the mean level in the lot. This was corroborated by results obtained from real composite samples. Many fruit or vegetables in trade are mixed after harvest to form combined lots. Analysis of composite samples provides a good indication of average residues but, where the lot has been mixed, such average values are potentially misleading. Residues monitoring is the best means available for general control of pesticide use and consumer exposure, but new strategies for sampling and analysis are required to address the combined effects of residues variability and mixing of lots.     

Phytochemical profiles and antioxidant activities of wine grapes

Grapes are rich in phenolics, flavonoids and resveratrol, which have been suggested to be responsible for their health benefits. The concentrations of phenolic, flavonoid, anthocyanins and resveratrol of 14 grape varieties grown in the Finger Lakes area of New York State were examined. Among the varieties tested, Cabernet Franc and Pinot Noir contained the highest total phenolic content with 424.6 ± 3.8 and 396.8 ± 12.4 mg/100 g, respectively. The total flavonoid content of Pinot Noir (301.8 ± 6.2 mg/100 g) was around 3.1-fold higher than that of Baco Noir. Baco Noir had the highest resveratrol content (571 ± 30 μg/100 g) of the varieties tested. Cabernet Franc possessed the highest antioxidant activity. Total antioxidant activities of grape extracts are well correlated with total phenolic content. The proliferation of Caco-2, HepG₂ and MCF-7 human cancer cells was significantly inhibited in a dose-dependent manner after exposure to Pinot Noir, Cabernet Franc, Chardonnay, Catawba, Concord, Sheridan, Niagara and Riesling. The results suggest that phytochemicals in the selected wine grapes have potent antioxidant and antiproliferative activities.     

Pesticide residues in conventional, integrated pest management (IPM)-grown and organic foods: insights from three US data sets

An analysis of pesticide residue data was performed to describe and quantify differences between organically grown and non-organic fresh fruits and vegetables. Data on residues in foods from three different market categories (conventionally grown, integrated pest management (IPM)-grown/no detectable residues (NDR), and organically grown) were compared using data from three test programmes: The Pesticide Data Program of the US Department of Agriculture; the Marketplace Surveillance Program of the California Department of Pesticide Regulation; and private tests by the Consumers Union, an independent testing organization. Organically grown foods consistently had about one-third as many residues as conventionally grown foods, and about one-half as many residues as found in IPM/NDR samples. Conventionally grown and IPM/NDR samples were also far more likely to contain multiple pesticide residues than were organically grown samples. Comparison of specific residues on specific crops found that residue concentrations in organic samples were consistently lower than in the other two categories, across all three data sets. The IPM/NDR category, based on data from two of the test programmes, had residues higher than those in organic samples but lower than those in conventionally grown foods.     

大米中敌稗残留量测定方法的研究

为贯彻实施敌稗农药最大残留限量国家标准 ,建立大米中敌稗残留量测定方法 ,试样用丙酮提取 ,石油醚萃取和弗罗里硅土净化 ,乙醚 -正己烷 (1∶1)淋洗。净化液用配有电子捕获检测器的气相色谱仪测定 ,外标法定量。方法最低检测浓度 4× 10 -4mg kg ,敌稗浓度在 0 2 0～ 2 0 0mg kg范围内 ,平均回收率为 89 7%～ 90 7% ,相对标准偏差为 4 4 6 %～ 5 2 1% ,符合农药残留分析的要求。     

茶叶中农药残留检测方法研究进展

茶叶中农药残留问题受到越来越多的关注,现代仪器分析技术在农残检测中的应用也在不断创新。本文主要综述了茶叶中农药残留检测方法的研究状况,对茶叶中农残检测样品前处理方法和检测技术进行了分析和比较。目前茶叶中农药残留检测方法主要有气相色谱法(gas chromatography,GC)、高效液相色谱法(high performance liquid chromatography,HPLC)、色谱-质谱联用法和酶联免疫吸附测定法(enzyme-linked immunosorbent assay,ELISA)。本文分析了不同检测方法使用的局限性和优越性,为不同性质的茶叶样品农残检测方法的选择提供了依据,旨在为茶叶中农药残留检测新方法的研究提供理论参考。     

食品中氨基甲酸酯类农药残留的检测方法研究进展

目前氨基甲酸酯类农药被广泛应用,其母体及代谢产物有较为严重的毒害作用。建立快速、灵敏、有效的氨基甲酸酯类农药残留的检测技术,成为当前研究者关注的课题。本文综述了近年来食品中氨基甲酸酯类农药残留分析的前处理及其检测技术,并对氨基甲酸酯类农药残留检测的发展前景进行了展望。     

广东省蔬菜水果中有机磷农药残留监测与评价

目的掌握广东省蔬菜、水果中有机磷农药的残留状况,为政府部门采取有效预防措施提供依据。方法自2001年起每年在全省各监测网点抽检各类新鲜蔬菜、水果,采用气相色谱仪和气相色谱质谱联用仪,参考GB/T 5009.20—2003《食品中有机磷农药残留量的测定》等分析方法进行检测。结果连续7年的监测共获得47400个检验数据,蔬菜、水果中有机磷的检出率和超标率分别为10.1%和8.0%,2001-2007年间,甲胺磷、甲基对硫磷、久效磷等国家禁止在蔬菜水果中使用的高毒高残留的有机磷农药还在普遍使用。结论广东省各地农产品中有机磷农药残留检出率和超标率变化趋势不明显,有机磷农药在蔬菜水果中的使用较为普遍。     

Occurrence of biogenic amines in wine: The role of grapes

The evolution of biogenic amines from must to wine has been studied in seven different grape cultivars before and after malolactic fermentation. Alcoholic and malolactic fermentations have been carried out using selected yeasts and bacteria that, in a previous study, were unable to produce biogenic amines. The study has been performed under aseptic conditions to exclude possible interferences due to uncontrolled contaminating microorganisms present in grapes and/or in the environment. The goal of this work was to investigate the influence of grape on biogenic amines content of the wine. The results obtained showed that grape variety is related to the presence of some biogenic amines in wines and that, climatic conditions also affect the accumulation of these compounds in grapes.     

北京市蔬菜、水果中有机磷农药残留现状调查

为了解北京市蔬菜、水果中有机磷农药残留情况，2002年在北京市抽检样品354件进行13种有机磷监测，其中蔬菜28l件，水果73件。检测结果显示7．6％的检品不符合国家标准。叶菜类(14，占9．3％)和根茎类(8，占17．4％)蔬菜的不合格率明显高于瓜菜、果菜类(2，占2．4％)蔬菜和水果(3，占4．1％)。13种有机磷检测出12种，其中禁用农药占53％。本市种植的蔬菜、水果与外埠进京产品的有机磷农药残留情况无显差别，超市、集贸市场、批发市场销售的产品的不合格率亦无显差别。     

Results from the monitoring of pesticide residues in fruit and vegetables on the Danish market, 1998?99

The objective of the Danish pesticide monitoring programme for fruit and vegetables was to check for compliance with the maximum residue levels in foods and to monitor the residue levels to assess the pesticide exposure of the Danish population. Sampling plans were designed based on previous findings and on food consumption data. Approximately 60% of the samples were selected on the basis of positive findings in samples from the previous 5 years. The remaining samples reflected the pattern of food consumption in Denmark. In addition, a rolling programme is maintained for commodities with a low consumption and no detected residues. Within each commodity, the sampling was random. Samples (n = 4150) of mainly fresh, conventionally grown fruit and vegetables were taken throughout the chain of suppliers including foodprocessing companies. Of the samples, 3% were frozen products and 2% were organically grown. Of the samples, 35% were of Danish origin, with 65% originating from other countries. Three accredited laboratories performed analyses of the samples using capillary gas chromatography, liquid chromatography and spectrophotometric methods. Results were registered online into a central database. Residues were found in 54% of the samples of fruit but only in 13% of the vegetables. Residues above the MRL were found in 4% of all samples of fruit and in 1% of vegetables.     

茶叶等农产品中二硫代氨基甲酸酯类农药残留快速检测方法的研究

目的研制快速检测茶叶等农产品中二硫代氨基甲酸酯类农药残留的装置及检测方法。方法试样中的二硫代氨基甲酸酯类农药被分解成易挥发的二硫化碳后,通入氮气将二硫化碳从基体中带出,导入吸收-显色液中,进行显色测定。结果平均回收率范围为83.5%～115.5%,相对标准偏差在4.00%～7.70%之间,当称取干样为5.0g时,定量检出限为0.6μg/g;当称取湿样为20.0g时,定量检出限为0.15μg/g。结论该比色测定方法简便、低成本,适用于农产品中二硫代氨基甲酸酯类农药残留的快速检测。在此基础上研制的比色卡,可用于农产品中二硫代氨基甲酸酯类农药残留的快速、简便测定。     

Organochlorine pesticide residues in cow's milk from a tropical region of Mexico

A monitoring study was conducted to assess the magnitude of DDT [(1,1,1-trichloro-2,2-bis( p -chlorophenyl)ethane)] and HCH (hexachlorocyclohexane) contamination of bovine milk from the central tropical region of Mexico as the chemicals are extensively used in livestock and public-health programmes. Among pesticide residues analysed, the milk samples collected from Tlalixcoyan showed a mean level of γ-HCH (0.128 mg kg -1 ), which was significantly higher than residues in milk samples from Medellin (0.049 mg kg -1 ) and Paso San Juan (0.022 mg kg -1 ). The mean level of pp '-DDE in Medellin samples (0.039 mg kg -1 ) was significantly higher than in Paso San Juan (0.018 mg kg -1 ) and Tlalixcoyan (0.024 mg kg -1 ) milk samples. The pp '-DDT mean level from Medellin milk samples (0.089 mg kg -1 ) was significantly higher than the levels detected in the other two areas. The highest mean Σ-DDT level detected in Medellin samples (0.146 mg kg -1 ) was three times the FAO/WHO tolerance level. The highest acceptable daily intakes calculated for Σ-DDT were 0.017 μg kg -1 bw day -1 for adults and 0.530 μg kg -1 bw day -1 for infants; for γ-HCH residues, they were 0.021 μg kg -1 bw day -1 for adults and 0.666 μg kg -1 bw day -1 for infants, indicating that infants are more exposed to pesticide residues. Results indicate that cattle exposure to HCH and DDT results in high levels in dairy milk and a potential health risk for consumers.     

加速溶剂萃取-气相色谱测定茶叶中多种农药残留

目的建立一种加速溶剂萃取(ASE)-气相色谱(GC)同时测定茶叶中三氯杀螨醇(有机氯类)与多种除虫菊酯类农药残留的新方法。方法样品用环己烷∶乙酸乙酯(1∶1,V/V)提取,提取液经florisil固相萃取柱净化后,采用气相色谱-电子捕获检测器(GC-ECD)进行检测。结果各农药在0.01、0.05、0.25mg/kg3个添加水平上的平均回收率都在90%以上,RSD在0.3%～3.8%之间。结论该方法快速、溶剂用量少、重现性好,能够满足茶叶中有机氯与拟除虫菊酯类农药残留的检测要求。