Pesticide residues in food--acute dietary exposure

Consumer risk assessment is a crucial step in the regulatory approval of pesticide use on food crops. Recently, an additional hurdle has been added to the formal consumer risk assessment process with the introduction of short-term intake or exposure assessment and a comparable short-term toxicity reference, the acute reference dose. Exposure to residues during one meal or over one day is important for short-term or acute intake. Exposure in the short term can be substantially higher than average because the consumption of a food on a single occasion can be very large compared with typical long-term or mean consumption and the food may have a much larger residue than average. Furthermore, the residue level in a single unit of a fruit or vegetable may be higher by a factor (defined as the variability factor, which we have shown to be typically x3 for the 97.5th percentile unit) than the average residue in the lot. Available marketplace data and supervised residue trial data are examined in an investigation of the variability of residues in units of fruit and vegetables. A method is described for estimating the 97.5th percentile value from sets of unit residue data. Variability appears to be generally independent of the pesticide, the crop, crop unit size and the residue level. The deposition of pesticide on the individual unit during application is probably the most significant factor. The diets used in the calculations ideally come from individual and household surveys with enough consumers of each specific food to determine large portion sizes. The diets should distinguish the different forms of a food consumed, eg canned, frozen or fresh, because the residue levels associated with the different forms may be quite different. Dietary intakes may be calculated by a deterministic method or a probabilistic method. In the deterministic method the intake is estimated with the assumptions of large portion consumption of a 'high residue' food (high residue in the sense that the pesticide was used at the highest recommended label rate, the crop was harvested at the smallest interval after treatment and the residue in the edible portion was the highest found in any of the supervised trials in line with these use conditions). The deterministic calculation also includes a variability factor for those foods consumed as units (eg apples, carrots) to allow for the elevated residue in some single units which may not be seen in composited samples. In the probabilistic method the distribution of dietary consumption and the distribution of possible residues are combined in repeated probabilistic calculations to yield a distribution of possible residue intakes. Additional information such as percentage commodity treated and combination of residues from multiple commodities may be incorporated into probabilistic calculations. The IUPAC Advisory Committee on Crop Protection Chemistry has made 11 recommendations relating to acute dietary exposure.     

氯氰菊酯在茼蒿和油麦菜上的残留行为研究

为考察氯氰菊酯在茼蒿和油麦菜上的残留行为,于2016年在山西、山东、天津、安徽、云南和河南进行了氯氰菊酯在茼蒿和油麦菜上的规范残留田间试验。两种作物均包括6地的最终残留量试验和1地的消解动态试验。按照现行的蔬菜中拟除虫菊酯类农药残留测定的国家标准方法对样品进行检测,对方法的有效性进行了评价。田间试验结果表明:氯氰菊酯在茼蒿和油麦菜上的消解动态均符合准一级动力学方程,消解半衰期分别为3.2 d和1.8 d。最后一次施药3、5和7 d后,氯氰菊酯在茼蒿上的残留中值分别为1.64、1.19和0.89 mg/kg,在油麦菜上的残留中值分别为0.84、0.50和0.28 mg/kg。结合不同试验点试验期间昼夜平均气温发现,气温对氯氰菊酯在茼蒿和油麦菜上的残留量有明显影响。施药期间较低的气温下,氯氰菊酯在茼蒿和油麦菜上消解缓慢,残留风险明显增大。建议在实际生产中遇到低温天气应适当延长采收间隔期,另外在开展农药残留田间试验时应重视气象条件对残留试验结果的影响。     

Proportionality principle revisited – relationship between application rates and pesticide residue concentrations in food commodities

BACKGROUND

The proportionality principle has been broadly used for over 10 years in regulatory assessments of pesticide residues. It allows extrapolation of supervised field trial data conducted at lower or higher application rates compared to the use pattern under evaluation by adjustment of measured concentrations, assuming direct proportionality between the rates applied and the resulting residues. This work revisits the principle idea by using supervised residue trials sets conducted under identical conditions but with deviating application rates. Four different statistical methods were used to investigate the relationship between application rates and residue concentrations and to draw conclusions on the statistical significance of the direct proportionality assumed.

RESULTS

Based on over 5000 individual trial results, the assumption of direct proportionality was not confirmed to be statistically significant (P > 0.05) using three models: direct comparison of application rates and residue concentrations ratios and two linear log-log regression models correlating application rate and residue concentration or only residue concentrations per se. In addition, a fourth model analysed deviations between expected concentrations following direct proportional adjustment and measured residue values from corresponding field trials. In 56% of all cases, the deviation was larger than ±25%, which represents the tolerance usually accepted for the selection of supervised field trials in regulatory assessments.

CONCLUSION

Overall, the assumption of direct proportionality between application rates and resulting residue concentrations of pesticides was not statistically significant. Although the proportionality approach is highly pragmatic in regulatory practice, its use should be considered carefully on a case-by-case basis. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Sequential sampling for incidence of phomopsis leaf blight of strawberry

ABSTRACT Sequential sampling models for estimation and classification were developed for the incidence of strawberry leaflets infected by Phomopsis obscurans. Sampling protocols were based on a binary power law analysis of the spatial heterogeneity of Phomopsis leaf blight in commercial fields in Ohio. For sequential estimation, samples were collected until mean disease incidence could be estimated with a preselected coefficient of variation of the mean (C). For sequential classification, samples were collected until there was sufficient evidence to classify mean incidence as being below or above a threshold (p(t)) based on the sequential probability ratio test. Monte-Carlo simulations were used to determine the theoretical average sample number (ASN) and probability of classifying mean incidence as less than p(t) (operating characteristic) for any true value of incidence. Estimation and classification sampling models were both tested with bootstrap simulations of randomly selected data sets and validated by data sets from another year that were not utilized in developing the models. In general, achieved (or calculated) C after sequentially sampling for estimation was close to the preselected C of 0.2, and mean incidence was estimated with little bias. Achieving a C of 0.1 with less than 75 sampling units (the nominal value for many original data sets) was more problematical, especially with true incidence less than 0.2. ASN for classification was only 9 to 18 at disease incidence values near p(t), and approximately five or less at incidence values far from p(t). Correct classification decisions were made in over 88% of the validation data sets. Results indicated that it is possible to estimate Phomopsis leaf blight with high precision and with high correct classification probabilities.     

嘧霉胺在蓝莓中的残留行为及膳食风险评估

为明确嘧霉胺在蓝莓上施用后可能产生的膳食暴露风险,通过规范的田间残留试验,检测了蓝莓中嘧霉胺的残留量,结合GEMS/FOOD中关于中国各年龄段居民97.5%位点的浆果类农产品膳食消费量及体重调查数据、每日允许摄入量 (ADI),评估了嘧霉胺对中国各消费人群的长期膳食摄入风险。结果表明:在0.01~1 mg/kg添加水平范围内,嘧霉胺的平均回收率在97%~100%之间,相对标准偏差（RSD）在4.5%~12%之间;嘧霉胺在蓝莓中的检测方法定量限（LOQ）为0.01 mg/kg。露地栽培模式下,嘧霉胺在蓝莓中的消解速率符合一级反应动力学方程,消解半衰期为 3.2 d。嘧霉胺按有效成分360 g/hm2施药2次,每次间隔7 d,药后3、5、7、10 d 时蓝莓中嘧霉胺的残留量为 0.18~1.54 mg/kg。膳食风险评估表明,在膳食消费量97.5%位点处,蓝莓中嘧霉胺残留对各消费人群长期膳食摄入风险的贡献率小于0.1%,说明通过蓝莓摄入嘧霉胺残留对人体产生的长期膳食摄入风险较小。     

吡唑醚菌酯和戊唑醇在桃中的残留与膳食风险评估

为评估桃中吡唑醚菌酯和戊唑醇残留的膳食风险，开展了8个典型地域的规范残留试验，研究了收获期2种农药残留物在桃中的最终残留。利用高效液相色谱-三重四极杆串联质谱仪 (HPLC-MS/MS)，通过改进，建立了吡唑醚菌酯和戊唑醇在桃中残留的分析方法。结果表明:在0.01~4.0 mg/L质量浓度范围内，吡唑醚菌酯和戊唑醇的进样浓度与峰面积之间具有良好线性关系(R2≥0.9906)。添加水平为0.01~4.0 mg/kg时，桃中吡唑醚菌酯的回收率范围为88%~92%，相对标准偏差 (RSD) 为5.6%~18.7%，戊唑醇的回收率范围为96%~106%，RSD为0.8%~13.2%。吡唑醚菌酯和戊唑醇在桃全果中的半衰期分别为7.9~13.9 d和5.4~8.9 d；在桃全果中的残留中值 (STMR) 分别为0.037和0.053 mg/kg，最高残留值 (HR) 分别为0.16和0.24 mg/kg。距末次施药后28 d，桃中吡唑醚菌酯和戊唑醇残留量对风险商 (RQ) 的贡献率 (RQc) 分别为0.02%和0.03%，说明通过桃摄入的吡唑醚菌酯和戊唑醇对我国一般人群产生的长期膳食暴露风险较低。对于短期膳食暴露风险，吡唑醚菌酯和戊唑醇的国家估算短期摄入量 (NESTI) 分别占急性参考剂量 (ARfD) 的0.4%和2%，对于1~6岁儿童分别占2%和4%，短期膳食暴露风险亦处于可接受水平。基于本次规范残留试验结果，总体上可认为，严格按照良好农业操作规范和标签推荐的方式施用，吡唑醚菌酯和戊唑醇在桃树上使用的长期和短期膳食暴露风险均是可接受的。     

A review of the effect of different application rates on pesticide residue levels in supervised residue trials

Residue trial data reported by the Joint FAO/WHO Meeting on Pesticide Residues (JMPR) have been reviewed to establish whether or not the resulting residues in harvested commodities are proportional to the pesticide application rate used on the crop. Numerous sets of trials were identified where the only parameter varied was application rate or spray concentration. Analysis of this database in terms of application rate, spray concentration, formulation type, preharvest interval, crop, pesticide, residue level and application type confirms that residues scale with application rate (proportionality principle). It is anticipated that use of the proportionality principle by regulators and those interested in evaluating pesticide residue data will improve pesticide risk assessment.     

国际上农药登记残留试验作物区域划分及试验点数要求

足够的残留试验点数及合理的试验区域划分是农药登记残留试验的重要组成部分。就联合国粮农组织(FAO)、经济合作与发展组织(OECD)及美国环境保护局(EPA)规定的农药登记残留试验点数及试验区域划分相关准则进行了综述,并简要介绍了国内外农作物种植区域划分情况及规定,旨在为我国农药登记残留试验的点数选择及区域划分提供建议。     

QuEChERS-高效液相色谱-串联质谱法检测吡噻菌胺、肟菌酯及代谢物在番茄中的残留及长期膳食风险评估

建立了吡噻菌胺及其主要代谢物1-甲基-3- (三氟甲基)-1H-吡唑-4-甲酰胺 (PAM)和肟菌酯及其代谢物肟菌酸在番茄中残留的分析方法。样品经乙酸-乙腈提取，无水硫酸镁、N-丙基乙二胺 (PSA)和石墨化碳黑 (GCB)净化，高效液相色谱-串联质谱 (HPLC-MS/MS)检测。结果表明:吡噻菌胺、PAM、肟菌酯和肟菌酸在0.025~2 mg/L范围内的线性关系良好，R2≥0.999 2。在不同添加水平下，4种化合物在番茄中的平均回收率在88%~97%之间，相对标准偏差 (RSD)小于3.9%，定量限 (LOQ)均为0.05 mg/kg。按照《农作物中农药残留试验准则》在全国12个地区开展规范残留试验，30%吡噻菌胺 ? 肟菌酯悬浮剂以推荐剂量有效成分270 g/hm2，于番茄灰霉病发生初期喷雾施药2次，施药间隔7 d (推荐的安全间隔期为5 d)。在分别于末次施药后5和7 d采集的番茄样品中，吡噻菌胺的残留量均低于0.26 mg/kg，肟菌酯的均低于0.33 mg/kg，均未超出中国制定的吡噻菌胺和肟菌酯在番茄中的最大残留限量 (MRL)值。根据田间残留试验结果、膳食结构和毒理学数据进行了长期膳食风险评估。结果表明:普通人群吡噻菌胺和肟菌酯国家估算每日摄入量 (NEDI)分别为0.1382和0.2645 mg，膳食风险商 (RQ)均小于100%，说明在推荐的良好农业规范 (GAP)条件下施用30%吡噻菌胺 ? 肟菌酯悬浮剂不会对人体健康产生不可接受的风险。     

比例推算法在国际食品法典农药最大残留限量评估中的应用

比例推算是指农药使用剂量与收获后农产品中的农药残留量之间具有一定的比例关系。假定该施药剂量与残留量的比例推算关系独立于作物类型、农药种类和施药方式,则超过临界良好农业规范(cGAP)标签范围±25%的施药剂量所导致的农药残留量将可以按比例进行归一化调整,从而增加了可用于评估农药最大残留限量(MRL)的残留数据。对国际食品法典农药残留委员会(CCPR)将比例推算应用于评估农药MRL的历史背景、制定过程以及最终提交给国际食品法典委员会(CAC)审议的比例推算应用指导原则的具体内容进行了综述,总结了采用比例推算法评估MRL的10项指导原则。使用比例推算法有利于增加评估农药MRL时的残留数据,推进农药MRL标准的制定进程。     

贵州地区茶叶及茶汤中氯氰菊酯残留量检测及其摄入风险分析

采用气相色谱建立了茶叶样品中氯氰菊酯残留量检测方法;通过对贵州省市售茶叶样品中氯氰菊酯的残留情况进行抽检,以了解其市售茶叶的安全性;通过田间试验制备浸泡实验用茶叶样品,设计正交实验研究了影响茶汤中氯氰菊酯浸出率的因素。结果表明,市场抽检茶叶样品中氯氰菊酯残留量平均值为0.919 mg/kg,最高残留量为1.52 mg/kg,低于茶叶中氯氰菊酯的最大残留限量(MRL)标准20 mg/kg;正交实验表明,浸泡次数和浸泡时间是影响氯氰菊酯浸出率的主要因素,茶汤中氯氰菊酯的最高浸出率为5.76%。按人均最高泡茶用量13 g/d计算,由饮茶而进入人体 的氯氰菊酯的最大量为1.5×10-2 mg/d,按氯氰菊酯每日最大允许摄入量(ADI)为0.05 mg/kg bw、 平均体重60 kg计,则其安全系数(K)为200。     

Dichlorvos residues in food arising from the domestic use of dichlorvos PVC strips

Trials have been carried out with “VAPONA”

1 “VAPONA” is a Shell trade mark.

Pest Strips under practical conditions in houses in the U.K. and France. The purpose of these trials was to determine the residues of dichlorvos that occur in food prepared in kitchens in which strips were placed. Samples, each of which consisted of the combined food and drink for an adult for a day, were taken at intervals during the trials. The food items were exposed and the meals prepared, including any cooking, in the way normal to the household. The analyses for dichlorvos were carried out by a g.l.c. method using flame photometric detection. The results show that the residue concentrations from all the individual samples were less than 0.1 part/million. In the U.K. trial, the mean dichlorvos levels in samples taken 7, 42 and 70 days after the strips were hung were 0.03, 0.03 and 0.02 part/million respectively. In the French trial, the mean concentrations were a little lower, being 0.02, 0.02 and less than 0.01 part/million at the same times. The items of food and the way in which they were processed varied widely from sample to sample and also between the two countries. However, the residue concentration in a sample did not appear to be correlated with the food items or with the manner of processing. No relationship was observed between the volume of the kitchens used, which varied from 14 to 45 m³, and the level of residues found in the samples.     

浙江省芹菜中农药多残留水平及累积急性膳食摄入风险初评

为明确浙江省各地区芹菜中农药残留水平以及对人群的膳食摄入风险,采用蔬菜中农药残留的标准检测方法,对在浙江省各地区采集的210个芹菜样品进行了检测,并就其累积急性膳食摄入风险开展了初步评估。结果表明:210个芹菜样品中共检出35种农药,检出率为94.8%,其中杀虫剂23种,杀菌剂11种,除草剂1种;97.1%的样品中的农药残留量低于其在芹菜中的最大残留限量 (MRL),残留水平整体较低;检出4种及4种以上农药残留的样品占总样品量的54%,存在农药多残留现象。采用相对强度系数 (RPF) 法将具有相同作用机制的农药分组,依据各农药的毒理学数据计算了各组农药的累积当量浓度,并针对不同人群进行了累积急性膳食摄入风险评估。结果显示:拟除虫菊酯类、三唑类、有机磷类、烟碱类及氨基甲酸酯类农药对儿童的急性膳食摄入风险 (%ARfD) 分别为60.35%、46.96%、20.15%、20.76%和12.40%;对一般人群分别为51.70%、40.20%、17.25%、17.77%和10.65%;所检出5类农药对各群体的%ARfD值均小于100%,表明芹菜中农药残留量及膳食摄入风险总体处于可接受水平。     

Establishment of Maximum Residue Levels for minor uses

The availability of plant protection products that are authorized for minor uses in the European Community is becoming restricted due to the stringent EU review process. An associated problem is the lack of sufficient residues data for minor uses necessary for the establishment of MRLs (Maximum Residue Levels). The policy for MRL setting is focussed on a high protection level for the consumer. Good Agricultural Practice (GAP) forms the basis for MRL setting together with supervised residues trials according to GAP. The MRL can be set when risk assessment shows no risk for the consumer. Rules to extrapolate residues data from major crops to minor crops can sometimes be derived from, for example, morphological properties of the crop, provided the GAP is similar, but for many minor crops this is not possible. In these cases residues trials performed on the minor crop are required to set an MRL, however, performing residues trials is not profitable for the plant protection industry, because of their limited financial return. Activities to facilitate the setting of MRLs for minor crops have been initiated both within the EU and CODEX.     

联苯菊酯、噻虫嗪及其代谢物噻虫胺在小麦上的残留及膳食风险评估

建立了小麦及其秸秆中联苯菊酯、噻虫嗪和代谢物噻虫胺残留量的分析方法。样品经乙酸-乙腈提取,无水硫酸镁、N-丙基乙二胺 (PSA) 及GCB净化,超高效液相色谱-三重四极杆串联质谱仪 (UPLC-MS/MS) 检测。结果表明:在0.0025~0.1 mg/L范围内,联苯菊酯、噻虫嗪和噻虫胺的峰面积与其质量浓度间呈良好线性关系,R2均大于0.99。麦粒样品在0.01、0.1和0.5 mg/kg,秸秆样品在0.05、0.5和3 mg/kg添加水平下,联苯菊酯、噻虫嗪和噻虫胺在小麦及其秸秆中的添加回收率分别在93%~98%、87%~98%和87%~98%之间,相对标准偏差 (RSD) 分别在0.8%~4.8%、0.6%~4.1%和1.0%~3.3%之间。按照《农作物中农药残留试验准则》在全国12个小麦主产区开展规范残留试验,采用35%联苯菊酯 ? 噻虫嗪悬浮剂,以制剂用量150 g/hm2 (有效成分52.5 g/hm2) 的剂量,于小麦蚜虫始盛时期施药1次,施药后间隔14 d和21 d采集的麦粒中联苯菊酯、噻虫嗪和噻虫胺的残留量结果验证了相关残留限量 (MRL) 值的适用性,且多点试验的结果具有更高的可靠性。长期及短期膳食暴露风险评估结果表明,小麦中联苯菊酯、噻虫嗪和噻虫胺残留量对1~6岁儿童和普通人群产生的膳食暴露风险在可接受范围内。     

韭菜中腐霉利的残留检测及长期膳食暴露评估

建立了一种简便、高效的QuEChERS前处理结合高效液相色谱-串联质谱 (HPLC-MS/MS) 检测韭菜中腐霉利残留量的方法。于2019年在中国黑龙江、辽宁、河南、山东、安徽、湖南、广西及福建8地开展了田间规范残留试验,研究了腐霉利在韭菜中的残留风险,并进行了韭菜中腐霉利残留的长期膳食暴露评估。样品采用乙腈提取,N-丙基乙二胺 (PSA) 和石墨化碳黑 (GCB) 净化,HPLC-MS/MS检测,外标法定量。结果表明:在添加水平为0.02~20 mg/kg范围内,腐霉利在韭菜中的回收率为74%~98%,相对标准偏差 (RSD) 为4.6%~9.9%,定量限 (LOQ) 为0.02 mg/kg。50%腐霉利可湿性粉剂以有效成分450 g/hm2的剂量于韭菜灰霉病发病初期或前期施药1次,施药后间隔30 d采样,腐霉利在韭菜中的最终残留量为0.04~1.06 mg/kg。长期膳食暴露评估结果显示:腐霉利的国家估算每日摄入量 (NEDI) 为2.5562 mg,风险商值 (RQ) 为40.6%,表明腐霉利在韭菜中的长期膳食摄入风险较低。     

Variability in initial spray deposit in apple trees in space and time

Variation in pesticide residues in space and time has not been investigated systematically in spite of the large variability found at single scales (e.g. between trees or orchards). Information on variability at different scales will support the development of sampling methods and more reliable prediction of residues. Experiments were conducted to quantify the spatiotemporal variability in initial spray deposit on apple leaves and fruit using a substitute tracer (zinc EDTA chelate). Five hierarchical spatial scales were defined as (1) between orchards, (2) between plots within an orchard, (3) between trees within a plot, (4) between zones within a tree and (5) between leaves/fruit within a zone. Similarly, two temporal scales were defined as (1) between applications within a single year and (2) between years. The initial zinc concentration was approximately log-normally distributed; the variability in initial deposit concentration was greater on leaves than on fruit. The average initial zinc deposition was significantly greater in the top and outside zones than in the middle zones within individual trees. The most important scale for driving residue variability is the within-zone unit-to-unit variation, contributing to 71 and 49% of the observed variability for leaf and fruit samples respectively. Variability at other scales was related to the variation in the tree architecture. The results indicated that stratified sampling on the basis of within-tree zone structures, with the effort focused on within-zone sampling, should be used for the determination of pesticide residues.     

稻谷加工过程中4种常用杀虫剂残留的消解规律

为控制水稻籽粒中农药的残留量,提高稻米食用的安全性,研究了稻谷中三唑磷、毒死蜱、丁硫克百威和氯虫苯甲酰胺4种杀虫剂从农田到餐桌的残留消解规律,阐明了水稻生长后期4种农药的施药期、用药量、采收间隔期与籽粒中农药残留分布的关系,并结合食用加工过程,分析了稻米入口前农药的残留消解情况,评估了稻米食用的安全性。田间试验参照农药登记残留试验准则进行,采用液相色谱-串联质谱法测定4种农药在稻谷不同加工过种中的残留量。结果表明:脱壳和碾米2种稻谷加工过程对4种农药的去除具有促进作用,其加工因子 (P_F) 均小于0.5;稻米食用加工过程中淘洗2次结合高压蒸煮可有效降低4种农药在稻米中的残留量,P_F<0.2,可进一步提高农药摄入的安全性。农药种类、施药剂量与采收间隔期和稻米的安全性密切相关。氯虫苯甲酰胺和丁硫克百威主要分布在稻壳和谷糠中,两者占总含量的85%以上,因此即使蜡熟期施药1次,采收间隔期21 d,2种农药也均未检出;而毒死蜱和三唑磷在收获后的籽粒中仍有检出,残留量范围分别为0.032~0.043 mg/kg和0.053~0.073 mg/kg。精米中三唑磷含量分配比随采收间隔期延长先降低后增加,其累积具有显著的滞后性,使得三唑磷残留量高于中国国家标准中规定的最大残留限量 (MRL) 0.05 mg/kg,应适当延长采收间隔期以降低其最终残留量。即使在乳熟期施药,所有剂量处理收获后的大米经淘洗2次结合高压蒸煮后,4种农药的残留水平均低于MRL值。因此,适当的食用加工方式能够有效降低稻米中农药的残留量,提高稻米食用的安全性。     

福建省主产区普通白菜中农药残留水平及膳食暴露风险评估

为评估福建省主产区普通白菜中农药残留水平及对人体的膳食暴露风险,采用现有的标准检测方法,对在福建省主产区采集的88个普通白菜样品中的68种农药残留进行了检测分析,并对检出农药进行了短期和长期膳食暴露风险评估。结果显示：88个普通白菜样品中,共有68个样品检出了农药残留,总检出率为77.27%;共检出27种农药,其中杀虫剂18种,杀菌剂9种;检出2种及2种以上农药残留的样品占检出农药残留样品总量的83.82%,存在农药多残留现象。利用相关农药的毒理学数据——急性参考剂量(ARfD)和每日允许摄入量(ADI)、农药残留数据和普通白菜的膳食消费量数据,评估了所检出农药的短期和长期膳食暴露风险。其中,短期膳食暴露风险值(%ARfD)范围为0～90%,长期膳食暴露风险商贡献率(RQc%)范围为0～46%。研究表明,福建省主产区普通白菜中的农药残留水平较低,通过食用该地区生产的普通白菜对消费者的农药残留膳食暴露风险整体在可接受范围内。     

菠菜中3种新烟碱类杀虫剂多残留分析方法研究

寄生隐丛赤壳菌是引起板栗疫病的致病菌。为建立该菌的分子检测技术,本研究首先采用通用引物 ITS1／ITS4对分离自四川雅安、泸州及重庆的寄生隐丛赤壳菌及其他参试菌株的 ITS 区进行 PCR 扩增和测序比对。根据该片段与 GenBank 中隐丛赤壳属其他种的 ITS 序列差异,设计了寄生隐丛赤壳菌的特异性引物 ITSP1／ITSP2,片段扩增大小为462 bp。利用该引物对菌株基因组 DNA 进行扩增,可以将寄生隐丛赤壳菌与其他参试菌区分开,检测灵敏度达30 pg。而以引物 ITS1／ITS4和 ITSP1／ITSP2进行的巢氏 PCR,可检测到30 fg 基因组 DNA,其灵敏度较常规 PCR 提高了1000倍。利用巢氏 PCR 检测体系对发病程度不同的组织和携菌组织进行检测,均能快速稳定地检测出寄生隐丛赤壳菌。