肉鸡加工过程中沙门氏菌的污染监测及分析

目的对肉鸡屠宰加工的不同环节进行沙门氏菌监测,了解各个环节沙门氏菌的污染状况,分析肉鸡加工过程中沙门氏菌的污染来源及关键环节。方法选择河南省某大型肉鸡屠宰加工企业作为监测点,在肉鸡屠宰前、褪毛后、过预冷池后、被分割后和包装入库等环节及预冷池水、分割刀具案板和工人手等处分别采集样本,共计1756份,进行沙门氏菌检测及其血清型鉴定。结果于1756份样本中检出沙门氏菌阳性样本700份,检出率为39.9%。其中,褪毛后整禽的沙门氏菌检出率最高,达63.9%;其次为过预冷池后的整禽胴体,检出率为57.3%。屠宰加工环节中检出的沙门氏菌中肠炎沙门氏菌最多,占71.7%,其次为印第安纳沙门氏菌,占20.8%。结论肉鸡在养殖期间存在沙门氏菌污染,且在屠宰加工环节存在交叉污染,应针对相关环节进行重点控制和工艺改进。     

生鲜畜禽肉中沙门氏菌全基因组分析与分子溯源

依据GB 4789.4—2016对从长沙市生鲜市场随机采集的生鲜猪肉、鸡肉进行检验。结果显示:有20份生鲜猪肉样品检出沙门氏菌,检出率为83.3%;有20份生鲜鸡肉样品检出沙门氏菌,检出率为74.1%;总检出率为78.4%。通过对其中40株沙门氏菌进行全基因组测序与分子溯源研究,结果表明:20株猪源性沙门氏菌与20株鸡源性沙门氏菌按分子溯源分析可分为5个明显不同的聚类,清晰反映了沙门氏菌的污染源分布及交叉污染情况,实现了精准溯源;其中发现了15个致病基因,从基因层面阐明了沙门氏菌可能存在的致病基因与致病机制,提示了沙门氏菌潜在的致病风险;试验发现了15个耐药基因,从基因层面阐明了沙门氏菌可能存在的耐药基因与耐药机制。     

陕西省生鲜乳中β-内酰胺酶的检测与结果分析

本次检测共有149份生鲜乳样品,其中鲜牛乳96份,鲜羊乳53份。旨在了解陕西省生鲜乳中是否含有β-内酰胺酶及其残留状况。采用食品整治办[2009]29号指定检验方法4《乳及乳制品中舒巴坦敏感β-内酰胺酶类物质检验方法-杯碟法》。结果共检出17份β-内酰胺酶阳性样品,阳性样品检出率为11.4%。17份阳性样品中,鲜牛乳9份,鲜牛乳阳性样品检出率为9.4%;鲜羊乳8份,鲜羊乳阳性样品检出率为15.1%。17个阳性样品的dA与dB差值较大在6.08-13.3mm。本次检测样品阳性检出率较高为11.4%,且阳性样品中所残留的β-内酰胺酶含量较高,可见生鲜乳中抗生素和β-内酰胺酶监管形势依然严峻。     

两种选择性培养基HE、CAS检测沙门菌效果的比较

目的 比较两种沙门菌选择性培养基HE和CAS在食物样本检测中的敏感性、准确性和时效性.方法 观察典型沙门菌和非沙门菌在两种选择培养基上的生长状况和菌落形态.通过人工染菌实验,比较两种选择性培养基分离沙门菌的检测效果.采集16份市售整鸡样本,进一步比较两种培养基沙门菌的阳性检出率.结果 沙门菌在HE平板上为绿色菌落,大多有黑心;在CAS平板上为紫色菌落.含菌量为10 CFU/25 g鸡肉样本,经SC增菌液增菌培养8h,可用CAS检出沙门菌;而采用HE则需增菌18 h才可检出.16份整鸡样本,增菌8,12和18 h,采用CAS的阳性检出率分别为43.75%、31.25%和37.5%,相应时间下采用HE的阳性检出率分别为18.75%,25%和18.75%,8份新鲜整鸡样本,检出4份阳性;8份冷冻整鸡样本,检出3份阳性.结论 CAS选择性平板可抑制大多杂菌生长,沙门菌在其上菌落形态较易鉴别.CAS分离沙门菌的检出时限和检测灵敏度都明显优于HE,建议在食物样本检测沙门菌时应首选CAS.     

黑龙江省肉鸡养殖和屠宰加工环节中沙门菌调查

目的了解黑龙江省肉鸡养殖和屠宰加工环节中沙门菌污染状况。方法根据国家食品安全风险监测专项《肉鸡养殖及屠宰加工环节沙门氏菌专项监测工作手册》规定的操作程序,并参考国家标准GB 4789.4—2010《食品安全国家标准食品微生物学检验沙门氏菌检验》对黑龙江省4个地市3 766份肉鸡样品进行检验。结果 4大环节共检测样品3 766份,检出阳性样品339份,检出率为9.00%,孵化、养殖、屠宰到配送分销4个环节均检出沙门菌,检出率分别为2.82%(22/781)、2.14%(11/515)、13.84%(220/1 590)、9.77%(86/880)。其中,屠宰环节的8种样品中预冷池水样品沙门菌检出率最高,为35.42%(34/96)。检出的沙门菌分属于9个血清型,以肠炎沙门菌和印地安纳沙门菌的比例最高。结论黑龙江省肉鸡屠宰和配送分销环节中沙门菌污染较严重。屠宰环节阳性率最高,是重要的污染环节,其中预冷池水中沙门菌检出率最高,是屠宰过程中肉鸡污染沙门菌的主要环节。     

内蒙古呼和浩特地区鸡源沙门氏菌分离鉴定、血清学鉴定及耐药性研究

目的 了解内蒙古呼和浩特地区市售整鸡的沙门氏菌污染状况,为建立食物污染及公共卫生安全提供数据支持。方法 2011～2012年仍呼和浩特地区采集冷冻、冷藏和现宰杀整鸡样品,迚行沙门氏菌的定性检测、血清分型及耐药性研究。结果 不同状态整鸡样品的沙门氏菌携带率明显不同,冷藏整鸡沙门氏菌检出率显著高于冷冻和现宰杀整鸡。血清型主要为肠炎沙门氏菌(Salmonella enteritidis)。36株沙门氏菌均对头孢替坦、亚胺培南最为敏感,对氨苄西林、哌拉西林、呋喃妥因、氨苄西林/舒巴坦、头孢唑林等表现出不同程度的耐药性,多重耐药菌株中五耐最为严重(25%)。结论 内蒙古呼和浩特地区鸡肉中的沙门氏菌多重耐药现象比较严重。     

全自动免疫磁珠分选系统检测沙门氏菌

目的研究全自动免疫磁珠分选系统对国标沙门氏菌检测方法的改进效果。方法从肉鸡专项监测中选取106份样品,采用全自动免疫磁珠分选系统和GB 4789.4-2010《食品微生物学检验沙门菌检验》进行沙门氏菌对比检测。与国标法相比,全自动免疫磁珠分选系统取消了SC和TTB增菌,经BPW增菌后直接使用系统富集目标菌并接种显色平板。结果免疫磁珠法阳性检出率为32%,国标法阳性检出率为31%,二者无显著性差异(P0.05)。但磁珠法取消了二次增菌的步骤,检测时间比国标法节省24 h,且平板上的单个菌落生长率和菌株特异性也更好。采用磁珠法检测的106份样品中,有34份样品检出可疑显色菌株,都有单个可疑菌落生长,最后均鉴定为目标菌沙门氏菌;采用国标法有38份样品检出可疑显色菌株,其中3份无单个可疑菌落生长经再次转种,最后有5株经鉴定为嗜水气单胞菌等干扰性杂菌,仅33株为目标菌沙门氏菌。结论全自动免疫磁珠分选系统特异性好、单个菌落生长率高且检测时间短,可以用于食品中沙门氏菌检验。     

湖南省调查——市售营养口服液七成含性激素

湖南省卫生防疫站食品卫生监督执法人员.随机采集在湖南省食品市场销售的全国各地产“食”字号营养口服液进行检测.检测结果表明,市售营养口服液七成含有性激素.测定的70份样品中,50份性激素阳性,检出率为71.4%.其中睾酮阳性样品36份,检出率为51.4%,雌二醇阳性产品39份.检出率为59.7%.二者同时检出的     

食源性致病菌检测结果分析

目的:对食源性致病菌进行检测,并对检测结果进行分析。方法:按照《食品安全国家标准食品微生物学检验》方法,对281份食品样品展开食源性致病菌检测研究。结果:在281份食品样品中,一共检测出25份致病菌阳性样本,阳性菌株29株。其中检出率最高的为弯曲菌(9.09%),最低的为金黄色葡萄球菌(0.42%)。结论:本次研究中的281份食品样品存在一定程度的食源性致病菌污染,以蜡样芽孢杆菌以及沙门氏菌为主。加大对食品安全性的检测,对餐饮食品加大监察力度,加强对肉制品、水果等致病菌的检测尤为重要,值得引起食品安全相关部门的注意。     

包装饮用纯净水微生物污染情况分析

目的检测宿迁市市售包装饮用水中大肠菌群和铜绿假单胞菌的污染情况。方法按照GB4789.3-2010(第二法)和GB/T 8538-2008对市场上抽取的包装饮用水样品进行大肠菌群和铜绿假单胞菌的检测。对检测数据使用SPSS软件进行差异显著性分析,对市售包装饮用水中大肠菌群和铜绿假单胞菌的污染情况以及两者的检出情况与产品包装规格的相关性进行分析。结果抽检的86份样品中有4份样品检出大肠杆菌,检出率为4.65%,22份样品检出铜绿假单胞菌,检出率为25.58%,检出大肠菌群、铜绿假单胞菌为阳性的样品均为桶装包装饮用水。大肠菌群的检出率与铜绿假单胞菌检出率之间存在极显著差异(x2=7.340,P=0.007)。结论宿迁市包装饮用水存在安全隐患,食品监管部门应加强监督管理,切实保障消费者健康。     

Ovarian structures and circulating steroids in heifers and lactating cows in summer and lactating and dry cows in winter

Two experiments compared follicular and luteal development and circulating steroid concentrations from induced luteolysis to ovulation in lactating Holstein cows (n = 27; 40.0 +/- 1.5 kg milk/day) vs. nulliparous heifers (n = 28; 11 to 17 mo-old) during summer (Experiment 1), and in lactating (n = 27; 45.9 +/- 1.4 kg milk/d) vs. dry cows (n = 26) during winter (experiment 2). All females received PGF2,, 6 d after ovulation and were monitored until next ovulation by daily ultrasound and assay of serum progesterone (P4) and estradiol (E2). Every female was used two or three times. In Experiment 1, lactating cows had high incidence of multiple ovulation (63.5%) compared with heifers (1.3%). Among single ovulators, there was no difference in maximal size of ovulatory follicles between lactating cows and heifers (15.8 vs. 16.5 mm, respectively). However, lactating cows had lower peak serum E2 (8.6 vs. 12.1 pg/ml), took longer to ovulate after luteolysis (4.6 vs. 3.8 d), developed more luteal tissue volume (7,293.6 vs. 5,515.2 mm3), and had lower serum P4 on d 6 after ovulation (2.0 vs. 3.0 ng/ml) than heifers (data included multiple ovulators). In experiment 2, multiple ovulations were similar between lactating and dry cows (17.9 vs. 17.2%, respectively). Peak serum E2 was also similar between lactating and dry cows (7.6 vs. 8.5 pg/ml) although lactating cows had larger ovulatory follicles (18.6 vs. 16.2 +/- 0.4 mm). Lactating cows took longer to ovulate (4.8 vs. 4.2 d), developed more luteal tissue (7,599 vs. 5,139 +/- 468 mm3), but had similar serum P4 (2.2 vs. 1.9 ng/ ml) compared with dry cows. Therefore, lactating cows had similar or lower circulating steroid concentrations than dry cows or heifers, respectively, despite having larger ovarian structures.     

Fertilization and early embryonic development in heifers and lactating cows in summer and lactating and dry cows in winter

Two experiments in two seasons evaluated fertilization rate and embryonic development in dairy cattle. Experiment 1 (summer) compared lactating Holstein cows (n = 27; 97.3 +/- 4.1 d postpartum [dppl; 40.0 +/- 1.5 kg milk/d) to nulliparous heifers (n = 28; 11 to 17 mo old). Experiment 2 (winter) compared lactating cows (n = 27; 46.4 +/- 1.6 dpp; 45.9 +/- 1.4 kg milk/d) to dry cows (n = 26). Inseminations based on estrus included combined semen from four high-fertility bulls. Embryos and oocytes recovered 5 d after ovulation were evaluated for fertilization, embryo quality (1 = excellent to 5 = degenerate), nuclei/embryo, and accessory sperm. In experiment 1, 21 embryos and 17 unfertilized oocytes (UFO) were recovered from lactating cows versus 32 embryos and no UFO from heifers (55% vs. 100% fertilization). Embryos from lactating cows had inferior quality scores (3.8 +/- 0.4 vs. 2.2 +/- 0.3), fewer nuclei/embryo (19.3 +/- 3.7 vs. 36.8 +/- 3.0) but more accessory sperm (37.3 +/- 5.8 vs. 22.4 +/- 5.5/embryo) than embryos from heifers. Sperm were attached to 80% of UFO (17.8 +/- 12.1 sperm/UFO). In experiment 2, lactating cows yielded 36 embryos and 5 UFO versus 34 embryos and 4 UFO from dry cows (87.8 vs. 89.5% fertilization). Embryo quality from lactating cows was inferior to dry cows (3.1 +/- 0.3 vs. 2.2 +/- 0.3), but embryos had similar numbers of nuclei (27.2 +/- 2.7 vs. 30.6 +/- 2.1) and accessory sperm (42.0 +/- 9.4 vs. 36.5 +/- 6.3). From 53% of the flushings from lactating cows and 28% from dry cows, only nonviable embryos were collected. Thus, embryos of lactating dairy cows were detectably inferior to embryos from nonlactating females as early as 5 d after ovulation, with a surprisingly high percentage of nonviable embryos. In addition, fertilization rate was reduced only in summer, apparently due to an effect of heat stress on the oocyte.     

2018年深圳市售蔬菜和鸡蛋中氟虫腈及其代谢物的检测分析

目的 建立超高效液相色谱-串联质谱法同时测定蔬菜和鸡蛋中氟虫腈及其代谢物(氟甲腈、氟虫腈砜和氟虫腈亚砜), 并对深圳市售的蔬菜和鸡蛋中氟虫腈及其代谢物残留状况进行抽样检测。方法 采用QuEChERS前处理方法, 以C18色谱柱为分离柱, 以乙腈和10 mmol甲酸+6 mmol甲酸铵水溶液为流动相进行梯度洗脱, 用超高效液相色谱-串联质谱(ultra performance liquid chromatography-mass spectrometry/mass spectrometry, UPLC-MS/MS), 电喷雾电离(electrospray ionization, ESI), 多反应监测(multiple reaction monitoring, MRM)模式检测, 外标法同时定量测定氟虫腈及其代谢物。结果 方法的线性范围为0.1~2.0 μg/L, 线性相关系数均大于0.9994, 检出限0.0005 mg/kg, 定量限0.001 mg/kg; 蔬菜中3个水平的平均加标回收率88.0%~101.2%, 相对标准偏差(relative standard deviation, RSD)均小于8.5%; 鸡蛋中3个水平的平均加标回收率86.1%~104.8%, 相对标准偏差(RSD)均小于9.2%。结论 该方法具有操作简单、干扰少、快速、准确可靠等特点, 可适用于蔬菜鸡蛋中氟虫腈及其代谢物的检测。     

Zinc and iron contents and their bioaccessibility in cereals and pulses consumed in India

Several cereals and pulses commonly consumed in India were screened for zinc and iron contents and their bioaccessibility in the same was determined by equilibrium dialysis employing an in vitro simulated digestion procedure. Zinc content of cereals ranged from 1.08 mg/100 g in rice to 2.24 mg/100 g in sorghum. Zinc content of pulses was between 2.03 mg/100 g (whole chickpea) and 2.68 mg/ 100 g (decorticated chickpea). Iron content of cereals ranged from 1.32 mg% in rice to 6.51 mg% in sorghum, while that of pulses ranged from 3.85 mg% in decorticated green gram to 6.46 mg% in black gram. Dialyzability of zinc from pulses (27–56%) was generally higher than that from cereals (5.5–21.4%). Dialyzabilities of iron were almost similar from both cereals and pulses examined and were 4.13–8.05% in cereals and 1.77–10.2 % in pulses. A significant negative correlation between inherent phytate content and zinc dialyzability value was inferred in the case of pulses. Phytic acid content of the cereals had a significant negative influence on iron dialyzability. Inherent calcium had a negative influence on zinc dialyzability in cereals. Tannin did not have any significant influence on zinc or iron dialyzabilities from cereals and pulses. While both insoluble and soluble fractions of the dietary fibre generally interfered with zinc dialyzability, the insoluble fraction alone had this effect on iron dialyzability. The lower collective negative influence of the inherent factors on zinc dialyzability from pulses is consistent with their higher concentrations in these grains, relative to cereals. The negative correlation of inherent phytic acid with zinc and iron dialyzabilities was supported by enhanced dialyzabilities of these minerals upon partial removal of phytate from the grains by treatment with fungal phytase.     

果蔬及其制品中真菌毒素的污染与检测研究进展

果蔬在生长、贮存、运输及加工等一系列过程中,极易受到各种病原菌的侵染而发生腐烂,腐烂果蔬不仅造成巨大的经济损失,而且导致果蔬积累大量的真菌毒素。真菌毒素可通过食物链的传递对人或动物的健康带来巨大威胁。本文就果蔬中常见真菌毒素的种类、产毒菌株、侵染途径、产毒条件、毒性作用、检测方法和限量标准等方面进行详细的总结,旨在为果蔬中真菌毒素的控制提供参考。     

蛋白质组学技术及其在乳及乳制品中的应用研究进展

蛋白质组学技术是近年来生命科学研究的重要工具,在食品、医学及动植物研究领域具有独特优势。利用蛋白质组学技术研究乳及乳制品,深入阐明其中蛋白质的表达及动态变化已成为当前的研究热点。该文主要综述了蛋白质组学的概念、常用技术及应用领域,重点介绍蛋白质组学在乳及乳制品领域,特别是在乳脂肪球膜蛋白、乳清蛋白、乳及乳制品加工过程以及干酪制品中的研究应用,探讨了目前乳及乳制品蛋白质组学研究中存在的问题与局限,并对蛋白质组学及其在乳及乳制品中的应用前景进行了总结与展望,为应用蛋白质组学技术深入研究乳及乳制品提供了理论依据。     

冰酒中的毕赤属和汉逊属酵母菌的筛选及其在葡萄酒酿造中的应用

从冰葡萄酒自然发酵过程中分离、鉴定出10株毕赤属(Pichia)和汉逊属(Hanseniaspora)酵母,对其耐受性(酒精、糖、酸、SO2)进行研究,筛选得到4株耐受性能优良的酵母菌株,编号为"HO"和"HU"(Hanseniaspora属)、"PO"和"PK"(Pichia属).再将此4个酵母菌株与商业酿酒酵母(S...     

Fenvalerate residue level and dissipation in tea and in its infusion

Fenvalerate is a non-systemic insecticide/acaricide used in controlling a wide range of pests, including those resistant to organochlorine, organophosphorus and carbamate insecticides. The study investigated the dissipation behaviour (residue level) of fenvalerate in tea and its transfer during infusion. Fenvalerate was applied on tea crop at two dosages, 100 and 200?g a.i.?ha^?1 (recommended and double the recommended) in the dry and wet seasons under field conditions. Samples (green tea shoots, made tea, its infusion and spent leaves) were analysed for fenvalerate by high-performance liquid chromatography using diode array detection. The residue dissipated faster in the wet season than in the dry season. Seven days after the treatment (normal round of plucking) the residues observed in the green shoots at the two dosages were 0.5?±?0.01, 1.1?±?0.01 and 0.4?±?0.02, 0.9?±?0.01?mg?kg^?1 in the dry and wet seasons, respectively. During processing of green tea shoots to made tea a 30–40% loss of residue was observed. The transfer of residue from made tea to infusion was in the range 10–30% for both seasons, whereas 50–70% of the residues remained in the spent leaves. However, the degradation rate in both seasons followed first-order kinetics. The half-lives were in the range of 2–3 days for green shoots and made tea in both seasons.     

Fenvalerate residue level and dissipation in tea and in its infusion

Fenvalerate is a non-systemic insecticide/acaricide used in controlling a wide range of pests, including those resistant to organochlorine, organophosphorus and carbamate insecticides. The study investigated the dissipation behaviour (residue level) of fenvalerate in tea and its transfer during infusion. Fenvalerate was applied on tea crop at two dosages, 100 and 200 g a.i. ha^-1 (recommended and double the recommended) in the dry and wet seasons under field conditions. Samples (green tea shoots, made tea, its infusion and spent leaves) were analysed for fenvalerate by high-performance liquid chromatography using diode array detection. The residue dissipated faster in the wet season than in the dry season. Seven days after the treatment (normal round of plucking) the residues observed in the green shoots at the two dosages were 0.5 ± 0.01, 1.1 ± 0.01 and 0.4 ± 0.02, 0.9 ± 0.01 mg kg^-1 in the dry and wet seasons, respectively. During processing of green tea shoots to made tea a 30-40% loss of residue was observed. The transfer of residue from made tea to infusion was in the range 10-30% for both seasons, whereas 50-70% of the residues remained in the spent leaves. However, the degradation rate in both seasons followed first-order kinetics. The half-lives were in the range of 2-3 days for green shoots and made tea in both seasons.     

生物技术在制浆造纸中的应用与研究进展

介绍了生物技术在制浆造纸工业的应用与研究进展，包括生物制浆、生物漂白、生物脱墨及造纸过程中的生物技术等。