对国家标准GB2763-2014中多菌灵、苯菌灵和甲基硫菌灵残留规定存在问题分析

根据我国多菌灵、苯菌灵和甲基硫菌灵的农药登记使用情况,对照国际食品法典委员会(CAC)、欧盟和日本等的农药残留规定,分析指出了GB 2763-2014《食品安全国家标准食品中农药最大残留限量》中有关多菌灵、苯菌灵和甲基硫菌灵在食品中的残留物定义和最大残留限量(MRLs)规定存在的问题,建议在GB 2763中规定苯菌灵和甲基硫菌灵残留定义同多菌灵,规定食品中多菌灵残留为多菌灵、苯菌灵和甲基硫菌灵残留量之和,使GB 2763规定更合理可行。     

甲基硫茵灵及其代谢物在不同种植模式黄瓜和土壤中的残留

采用液质联用仪比较分析了3个不同种植区域（江苏南京、广西南宁和湖南长沙）露地和大棚两种种植条件下黄瓜和土壤中甲基硫菌灵及其代谢物多菌灵的残留动态,同时对黄瓜中的最终残留量进行了比较分析。施药后,甲基硫菌灵在黄瓜和土壤中均能很快转化为多菌灵[施药后1 d甲基硫菌灵未检出（〈0.01 mg·kg-1）],多菌灵在露地黄瓜和土壤中的原始沉积量均低于大棚。3个试验点露地黄瓜中的半衰期分别为2.3、1.4 d和1.4 d,在大棚黄瓜中的半衰期分别为2.6、1.7 d和2.0 d。在3个试验点露地土壤中的半衰期分别为1.6、1.7 d和2.3 d,在大棚土壤中的半衰期分别为2.3、2.0 d和2.3 d。最终残留试验在最后一次施药后1 d采样时,大棚、露地黄瓜中的甲基硫菌灵均未检出（〈0.01 mg·kg-1）,多菌灵在3个试验点露地黄瓜中的最终残留量为0.014~0.162 mg·kg-1,而在3个试验点大棚黄瓜中的最终残留量为0.121~0.561 mg·kg-1。参照我国所制定的黄瓜中多菌灵的MRL（0.5 mg·kg-1）,露地种植方式下所有处理黄瓜中甲基硫菌灵代谢物多菌灵的最终残留量均符合国家标准的规定,但大棚种植方式下其残留量有超标的风险。     

液质联用测定番茄中甲基硫菌灵残留量

为了评价70%甲基硫菌灵可湿性粉剂在番茄中的使用安全性,开展甲基硫菌灵在番茄中的残留量研究。本文建立了分散固相萃取前处理,高效液相色谱/质谱联用法测定甲基硫菌灵在番茄中残留量的方法。样品经乙腈提取,乙二胺-N-丙基甲硅烷(PSA)和无水硫酸镁混合振荡离心除去杂质和水分,上清液用配有电喷雾(ESI)源的高效液相色谱/质谱联用仪测定。田间试验结果建议在番茄上喷施70%甲基硫菌灵可湿性粉剂562.5 g ai·hm-2,3次施药,推荐安全间隔期为3 d;市场抽检样品检测表明番茄中甲基硫菌灵的残留量均小于0.05mg·kg-1,低于最大残留限量3 mg·kg-1。     

橙汁加工过程对农药炔螨特残留的影响

为弄清橙汁加工过程中农药炔螨特残留的动态,通过田间喷施浓度为5倍于最高推荐剂量的农药溶液以强化炔螨特在甜橙上的残留,然后按照橙汁商业化加工过程进行加工,采用QuEChERS前处理技术结合气相色谱-串联质谱法检测炔螨特的含量,来考察橙汁商业化加工过程对炔螨特残留的影响。结果表明:炔螨特残留主要分布于甜橙果皮中,果肉中炔螨特的残留量不足全果的5%。清洗能除去全果中32.5%的炔螨特残留。初榨果汁、精滤果汁、非浓缩橙汁(NFC橙汁)和浓缩橙汁中的残留量分别为原料果的1.98%、1.95%、1.73%、1.37%,其中NFC橙汁和浓缩橙汁的加工因子分别为0.0173和0.0137,但炔螨特在果渣和精油中发生富集,加工因子分别为1.2822和18.4947。研究结果为橙汁加工工艺的优化和炔螨特残留的膳食暴露评估提供参考。     

复配杀菌剂防治平菇尖孢镰刀菌病害的效果测定

为筛选应用于平菇栽培的高效低残留杀菌剂,本试验研究了复配杀菌剂(使百功+多菌灵、使百功+克霉灵、多菌灵+克霉灵)对尖孢镰刀菌与平菇菌丝生长的影响及其在平菇栽培中的应用效果。结果表明,3种复配杀菌剂抑制尖孢镰刀菌菌丝生长的EC₅₀值分别为3.67、4.51和7.01 mg·L^-1,均显著小于对应的单药杀菌剂;3种复配杀菌剂抑制平菇菌丝生长的EC₅₀值分别为156.41、121.97和237.38 mg·L^-1,是其抑制尖孢镰刀菌菌丝生长EC₅₀值的27~43倍。在平菇栽培发酵料中使用0.1%~0.3%的复配杀菌剂使百功+克霉灵,菌丝生长速度加快,生物学效率升高;与未添加杀菌剂处理相比,污染率降低6.1~8.8个百分点;与使百功处理相比,平菇子实体中的农药残留量降低71.8%~76.6%。综上,复配杀菌剂能有效降低平菇子实体中的农药残留,其中使百功+克霉灵复配杀菌剂效果最好,是一种高效低残留的平菇枯萎病防治药剂。     

多菌灵在草莓与土壤中的残留动态研究

采用高效液相色谱（HPLC）分析方法,研究了多菌灵在草莓与土壤中的消解动态和最终残留。分析结果表明,多菌灵最低检出浓度为0.05 mg.kg-1,添加浓度在0.05～2.0 mg.kg-1范围内,回收率为81.6%～102.6%,变异系数为1.44%～5.35%。田间试验结果表明,多菌灵推荐浓度和加倍浓度在草莓中的消解动态方程分别为C=3.212 2e-0.1354t、C=8.810 3e-0.1379t,土壤中的消解动态方程分别为C=2.941 1e-0.1011t、C=6.173 3e-0.1144t。多菌灵消解较快,草莓中的消解半衰期为4.2～6.7 d,土壤中的消解半衰期为5.4～7.3 d。加倍浓度和推荐浓度各施药2次,30 d后残留量均降至0.1 mg.kg-1以下,低于多菌灵在果蔬中最大允许残留量（MRL）0.5 mg.kg-1。     

嘧菌环胺·异菌脲可湿性粉剂在葡萄和土壤中的残留消解动态及风险评估

通过对嘧菌环胺·异菌脲可湿性粉剂在葡萄和土壤中开展两年两地的残留消解和最终残留试验,旨在为该农药在生产上的使用及有效控制提供合理数据。本文依据《农药残留试验准则》设计田间试验方案并实施,利用气相色谱-三重四极杆串联质谱(GC-QqQ-MS/MS)对葡萄和土壤样品中的嘧菌环胺和异菌脲进行检测,对残留量用农药风险商和危险商公式计算。结果显示,嘧菌环胺在葡萄和土壤中的消解半衰期是6.6~11.2 d,异菌脲在葡萄和土壤的半衰期是1.7~18.7 d。结果表明,当采收间隔期7 d时,嘧菌环胺和异菌脲的残留量均低于我国规定的最大残留限量值,其风险商和危险商均小于100%,在可控风险范围之内。因此,嘧菌环胺·异菌脲可湿性粉剂在葡萄的生产中使用是安全的。     

内蒙古马铃薯农药残留及膳食风险评估

对内蒙古主产区马铃薯样品进行农药残留监测,并对检出农药进行了急性和慢性膳食摄入风险评估。结果表明,在341份马铃薯样品的58种农药残留监测中,检出农药23种,农药残留阳性率为49.9%。检出的23种农药的慢性膳食摄入风险(%ADI)和有急性参考剂量的11种农药的急性膳食摄入风险(%ARfD)均远低于100%,其中克百威的慢性膳食摄入风险最高,矮壮素的急性膳食摄入风险最高。随着消费者年龄的增加,矮壮素、氯苯胺灵、克百威、多菌灵4种农药的急性和慢性膳食摄入风险呈逐渐下降的趋势;这4种农药在不同食用方式下,不去皮水煮/微波煮和不剥离炸芯片/薯条食用的急性膳食摄入风险明显高于其他食用方式。总体上,内蒙古马铃薯块茎产品中检出的农药残留以低毒农药为主,农药的急慢性膳食摄入风险均很低。     

甘薯低糖脯加工工艺及关键设备研制

研究设计出一种甘薯脯加工工艺,经投产试验,可生产出含糖量为３５％左右的色、形、口感俱佳的粒状甘薯低糖脯。为适应其特殊性状加工要求,研制出的定向切片机,六方成型机等关键加工设备,既可满足该工艺要求,又可用于其它块茎类作物的切制工序。     

生防放线菌ZZ-9对4种杀菌剂及温度的敏感性测定

采用菌丝生长速率法,分别测定放线菌ZZ-9菌株对不同温度及不同药剂的敏感度,旨在为后期生物制剂的研究提供理论依据。结果表明,放线菌ZZ-9对供试4种杀菌剂均表现出一定的敏感性。其中,对戊唑·丙森锌最敏感,EC50值为82.99 μg/mL;对辛菌胺醋酸盐和苯醚甲环唑次之,EC50值分别为139.51 μg/mL和108.22 μg/mL;而对甲基硫菌灵的敏感性最低,EC50值为267.55 μg/mL。质量浓度为50 μg/mL时,戊唑·丙森锌、苯醚甲环唑、辛菌胺醋酸盐和甲基硫菌灵对该菌株的抑制率分别为46.09%、43.48%、39.13%、27.83%。放线菌ZZ-9菌株在35 ℃下生长最好,15 ℃和45 ℃下生长受到明显抑制。     

木霉对多菌灵的生物降解特性研究

从耐药性木霉菌株的诱变选育过程中,得到一株能在含多菌灵2 000 mg L-1培养基上生长的变异菌株T32。该菌株在以多菌灵为唯一碳源的无机盐培养基中,于25℃、200 rm in-1振荡培养5 d,对多菌灵的降解率达到61.4%。在pH6.0、25℃、5%接种量和加入0.5%酵母粉为最适降解条件下,该菌株对多菌灵、速克灵、扑海因、甲基布托津和三唑酮这5种常用化学农药的降解率分别达到91.4%、92.1%、55.3%、40.1%和86.5%。对原土壤、自然风干土壤和高温烘干土壤中的多菌灵进行室内降解实验,在25~28℃、5%接种量、含水量维持15%的条件下处理10 d,对多菌灵的降解率分别达到78.6%、75.3%和70.5%。     

Occurrence and distribution study of residues from pesticides applied under controlled conditions in the field during rice processing

The results of an experiment to study the occurrence and distribution of pesticide residues during rice cropping and processing are reported. Four herbicides, nine fungicides, and two insecticides (azoxystrobin, byspiribac-sodium, carbendazim, clomazone, difenoconazole, epoxiconazole, isoprothiolane, kresoxim-methyl, propanil, quinclorac, tebuconazole, thiamethoxam, tricyclazole, trifloxystrobin, λ-cyhalotrin) were applied to an isolated rice-crop plot under controlled conditions, during the 2009-2010 cropping season in Uruguay. Paddy rice was harvested and industrially processed to brown rice, white rice, and rice bran, which were analyzed for pesticide residues using the original QuEChERS methodology and its citrate variation by LC-MS/MS and GC-MS. The distribution of pesticide residues was uneven among the different matrices. Ten different pesticide residues were found in paddy rice, seven in brown rice, and eight in rice bran. The highest concentrations were detected in paddy rice. These results provide information regarding the fate of pesticides in the rice food chain and its safety for consumers.     

Effect of commercial processing on pesticide residues in selected fruits and vegetables

Commercial food processing operations such as washing, blanching, and cooking remove major portions of the pesticide residues that are currently permitted on the raw agricultural crop. These unit operations are reviewed for selected products, along with degree of residue removal at each step. For example, washing plus peeling removes 99% of carbaryl and malathion residues from tomatoes. Washing removes 83% of benomyl residue from tomatoes and further processing reduces the residue by 98% in tomato puree and catsup. Even in the most concentrated fraction from tomatoes (tomato paste), residues were below the initial level in the raw product.     

加工过程对水果及其制品中农药残留的影响

综述了国内外加工过程对水果中农药残留的影响,着重讨论了原料前处理和灭菌,以及榨汁、澄清、过滤、干燥、发酵等对农药残留的影响及其控制措施,并对今后该领域的发展前景进行了展望,以期为水果制品生产中减少农药残留、保障消费者食品安全提供一定的参考。     

辐照生姜的贮藏性状研究

8 0～ 2 5 0Gyγ射线辐照处理生姜 ,可以导致生姜贮藏初期Vc损失 ,但辐照处理能够抑制生姜的发芽和呼吸代谢作用 ,从中长期贮藏的角度来看 ,反而有利于Vc含量的维持。辐照处理还引起生姜贮藏过程中还原糖含量的增加 ,以 1 5 0和 2 5 0Gy剂量处理升高幅度最明显。2 5 0Gy辐照处理使生姜蛋氨酸和精氨酸含量明显下降 ,但对其余 1 6种氨基酸含量影响较小。生姜受到辐照后 ,短期内出现呼吸高峰 ,然后呼吸强度迅速下降 ,并维持在较低水平。 80～40 0Gy剂量辐照处理使生姜根茎肉质部电解质渗透率升高 ,但同样剂量的辐照没有引起生姜组织酯酶同工酶酶谱的变化     

Short-term soil CO2 emission after conventional and reduced tillage of a no-till sugar cane area in southern Brazil

The impact of tillage systems on soil CO₂ emission is a complex issue as different soil types are managed in various ways, from no-till to intensive land preparation. In southern Brazil, the adoption of a new management option has arisen most recently, with no-tillage as well as no burning of crops residues left on soil surface after harvesting, especially in sugar cane areas. Although such practice has helped to restore soil carbon, the tillage impact on soil carbon loss in such areas has not been widely investigated. This study evaluated the effect of moldboard plowing followed by offset disk harrow and chisel plowing on clay oxisol CO₂ emission in a sugar cane field treated with no-tillage and high crop residues input in the last 6 years. Emissions after tillage were compared to undisturbed soil CO₂ emissions during a 4-week period by using an LI-6400 system coupled to a portable soil chamber. Conventional tillage caused the highest emission during almost the whole period studied, except for the efflux immediately following tillage, when the reduced plot produced the highest peak. The lowest emissions were recorded 7 days after tillage, at the end of a dry period, when soil moisture reached its lowest rate. A linear regression between soil CO₂ effluxes and soil moisture in the no-till and conventional plots corroborate the fact that moisture, and not soil temperature, was a controlling factor. Total soil CO₂ loss was huge and indicates that the adoption of reduced tillage would considerably decrease soil carbon dioxide emission in our region, particularly during the summer season and when growers leave large amounts of crop residues on the soil surface. Although it is known that crop residues are important for restoring soil carbon, our result indicates that an amount equivalent to approximately 30% of annual crop carbon residues could be transferred to the atmosphere, in a period of 4 weeks only, when conventional tillage is applied on no-tilled soils.     

Variation in sugar levels and invertase activity in mature fruit representing a broad spectrum of Cucumis melo genotypes

Sugar accumulation is a very important physiological process that determines dessert-melon fruit quality. Considerable variation in the sugar content and composition in the mature flesh of Cucumis melo L. fruits was observed among 56 genotypes which represent the wide range of morphological and horticultural types found in this species. Sucrose accumulation was observed not only among 'dessert melons' of the inodorus and cantalupensis types, but also in representatives of other subgroups of C. melo, including some of the accessions from agrestis and conomon groups. Among the genotypes that accumulate sucrose, the levels of this sugar, and not of the hexoses, were correlated with the total sugar concentration. Hexose levels were correlated with total sugar levels only among low-sugar genotypes that did not accumulate sucrose. Activities of the sucrose hydrolyzing enzymes acid invertase (EC 3.2.1.26) and alkaline invertase (EC 3.2.1.27) were measured in the mature fruit flesh and the results of this survey support the hypothesis that low acid invertase activity is a prerequisite for sucrose accumulation. The sucrose accumulating, high sugar genotypes had less-acidic flesh pH values (pH> 6) than the low-sugar genotypes. The latter were characterized by a broader range of pH values, including acidic (pH< 5.5) fruit flesh.     

苹果果实中毒死蜱残留的品种间差异及套袋对毒死蜱残留的影响

为探讨苹果果实中毒死蜱残留的品种间差异及套袋对其残留的影响作用,采用气相色谱法（GC-FPD）,研究了不同品种苹果果实中毒死蜱的残留动态以及套袋对苹果果实不同部位中毒死蜱残留的影响。结果表明,毒死蜱在苹果果实中的残留量存在着明显的品种差异,其中红富士属于高农药残留的品种,而嘎拉、红将军和83-1-70-3则属于低农药残留的品种。毒死蜱在苹果果实不同部位中的残留量表现出明显差异,果皮是毒死蜱残留的主要部位,其次是全果,果肉中的残留最少。套袋明显减少了毒死蜱在苹果果实中的残留量,不论处理浓度和取样时间如何,套袋苹果果实中毒死蜱的残留量比不套袋至少减少1/3。