市售水产品中镉污染状况评价及健康风险评估

目的了解某市市售水产品鱼类、贝类、虾类、蟹类中重金属镉的污染状况,分析其镉含量的季节性差异,对水产品的镉污染程度进行等级划分,并评估其健康风险。方法采集市售水产品样品1 554份,采用石墨炉原子吸收光谱法测定各类水产品中的镉含量;通过描述性分析比较镉含量在季节之间的变化;采用单因子污染指数(Pi)法划分水产品的污染等级;以镉暂定每月可耐受摄入量(PTMI)为参考值,评估水产品的健康风险。结果水产品样品中重金属镉的平均水平为0.116 4 mg/kg;总检出率为45.56%(708/1 554),其中贝类、蟹类、虾类和鱼类的检出率依次为86.26%(496/575)、66.43%(93/140)、32.48%(102/314)和3.24%(17/525);总超标率为1.74%(27/1 554),其中蟹类、虾类、贝类和鱼类的超标率依次为7.86%(11/140)、2.87%(9/314)、1.22%(7/575)和0.00%(0/525);污染等级评价结果显示,蟹类在秋季为轻度污染水平(Pi值为0.36),在春冬两季为中度污染水平(Pi值分别为0.70和0.89),其余种类水产品在各季节中均呈清洁水平;健康风险评估结果表明,在一般消费水平下,不同季节四类水产品的每月评估摄入量(EMI)占PTMI的比值最大为0.35%,而在高消费水平下,EMI占PRMI的比值最大为49.33%。结论水产品中镉超标率在季节之间表现出一定的变化,夏季镉污染最轻;除蟹类存在有轻度或中度污染水平外,鱼类、贝类、虾类均为清洁水平;一般消费人群和高消费人群因摄入水产品而产生镉暴露健康风险的可能性均较低。     

2018年水产品国家食品安全监督抽检结果分析

目的 分析2018年我国水产品的食品安全形势。方法 汇总2018年水产品国家食品安全监督抽检结果, 对其不合格项目等信息进行分析。结果 2018年共抽检水产品1248批次, 检出不合格样品58批次, 总体合格率为95.4%, 其中鱼类的合格率为96.8%, 虾类和贝类的合格率分别为93.8%和91.1%, 蟹类的合格率仅为81.3%。淡水鱼和海水鱼的不合格原因主要是恩诺沙星残留超标, 贝类的不合格原因主要是检出禁用兽药氯霉素, 海水虾和海水蟹的不合格原因主要是镉超标。结论 蟹类、贝类、虾类等水产品的合格率偏低, 不合格原因主要是违规使用兽药和镉污染。     

南通市水产品中铅、镉含量分析与评价

了解南通市水产品中重金属的含量水平及卫生品质状况。2017年在南通市区范围内采集具有代表性的水产品,4类共440份样品,进行铅、镉含量检测,并采用单因子污染指数法对重金属污染等级及污染水平进行评价。南通市区4类水产品中铅、镉指标均有检出;鱼类、贝类、头足类铅、镉含量符合《无公害食品水产品中有毒有害物质限量》限量标准;甲壳类铅、镉均有超标,梭子蟹超标率最高,超标率分别为9.1%和18.2%。研究可为南通市水产品品质安全评价提供依据,为进一步研究重金属污染来源、富集及转移规律提供参考。     

三门市售水产品铅镉污染监测分析

正了解三门市售水产品铅镉污染物状况。方法:按照《食品安全国家标准食品中污染物限量》(GB2762-2012)对2013-2014年三门县14个乡镇农贸市场市售水产品进行铅、镉的检测。结果:水产品中铅含量基本符合标准要求,镉的超标率为0.74%,检出软体动物中的鱿鱼镉含量偏高,均值为0.18mg/kg。结论:水产品中的软体动物重金属含量稍有超标,建议加强海水养殖的环境监管,确保食品健康。     

广东省居民贝类水产品中镉暴露的风险评估

目的了解广东省贝类水产品中镉污染状况及居民对贝类水产品的消费情况,并对食用贝类水产品中镉暴露进行风险评估。方法采用随机抽样方法,在广东省的粤东、粤西和珠三角地区采集贝类水产品样品307份,监测其镉含量,并结合广东省居民贝类水产品消费量数据,采用点评估模型评价广东省居民贝类水产品中镉暴露风险。结果本次研究共检测307份样品,贝类水产品中镉总超标率为23.8%(73/307),中位数含量为0.630 mg/kg;粤东、粤西和珠三角地区的镉超标率分别为19.4%(13/67)、23.5%(16/68)及25.6%(44/172),中位数含量依次为0.530、0.806及0.853 mg/kg,差异无统计学意义(χ~2=0.94,P0.05)。人群摄入贝类水产品中镉的平均暴露量为0.957μg/d,高消费人群的暴露量为4.511μg/d;分别占暂定每月可耐受摄入量(PTMI)的1.91%和9.02%。结论广东省贝类水产品中镉含量存在一定程度的超标情况,但人群摄入贝类中镉暴露风险相对较低。     

广东省蟹类镉污染调查及评价

目的 了解广东省淡水蟹与海水蟹中镉的污染水平。方法 2013-2016、2018年在广东省21地市总共采集572份蟹类样品, 采用电感耦合等离子体质谱联用法检测样品中镉含量。结果 5年监测显示广东省蟹类产品超标率约为30%, 镉含量均值为0.688 mg/kg, 中位数为0.208 mg/kg; 其中海水蟹是广东地区主要的食用蟹种类, 但其镉含量较高, 中位数为0.231 mg/kg, 超标率是淡水蟹的10倍; 其次通过对样品产地进行分析, 非沿海城市的蟹类主要源自于沿海城市的海水蟹, 并同样含有较高水平的镉污染。针对蟹的不同食用部位进行细化检测, 其中蟹黄蟹膏镉超标率约为80%, 含量高于2 mg/kg。结论 广东省蟹类镉污染仍处于较高水平; 含镉量较高的蟹以海水蟹为主, 同时蟹黄、蟹膏食用镉暴露风险高于蟹肉。应针对性的提升对小型餐饮业的卫生管理, 同时加大对重金属环境污染的治理, 从源头以降低蟹等水产品镉污染的风险。     

瓯海区市售海产品中重金属的含量及评价

目的:了解温州市瓯海区市售海产品中的重金属元素铅、镉、汞的含量水平,评估其污染状况,并进行健康风险评价,为保障人们的饮食安全提供科学依据。方法:在水产品流通环节进行采样,采样点包括瓯海全区13个镇、街道的超市、农贸市场、专营店及批发市场4大场所,共计203份,利用石墨炉原子吸收分光光度法测定铅和镉,利用原子荧光光谱法测定汞。结果:共检测了203份样品。其中铅检出率为92.1%,超标率为1.0%;镉检出率为86.2%,超标率为8.9%;汞检出率为96.1%,超标率为0。结论:瓯海区市售海产品中重金属状况总体较好,甲壳类海产品中的镉超标,存在一定的安全风险,应引起高度重视。     

杭州市近江市场食用贝类中重金属含量调查及评价

调查了杭州市主要贝类市场--近江市场食用贝类中重金属铅(Pb)、镉(Cd)、铜(Cu)、汞(Hg)和砷(As)的含量,并采用<农产品安全质量无公害水产品安全要求>(GB18406.4-2001)及我国食品相关重金属限量标准对检验结果进行评价.检测结果显示:杭州市近江市场所售食用贝类中铅含量0.048～0.596 mg/kg,均值0.184mg/kg;镉含量0.11~2.17 mg/kg,均值1.24 mg/kg;铜含量1.01~43.4 mg/kg,均值10.4 mg/kg;汞含量0.010～0.031mg/kg,均值O.018mg/kg;无机砷含量O.11-O.84mg/kg,均值0.42mg/kg.评价结果表明,杭州市近江市场上食用贝类中Cu、Hg、As含量均低于GB18406.4-2001的限量标准,但Pb和Cd超标,尤其是Cd超标严重.其中,铅超标率20%.Cd超标率为1OO%.说明该市场所售贝类产品存在食用风险,应予以重视.     

2009年广东省市售大米及其制品镉污染状况调查

目的了解广东省市售大米及其制品镉污染现状,为开展食品中镉暴露风险评估提供参考依据。方法于2009年9月在广东省21个地级市采集市售大米及干米粉共840份,其中大米420份,干米粉420份,采用石墨炉原子吸收光谱法进行镉含量测定,采用秩和检验和χ2检验进行统计学分析。结果 2009年广东省市售大米及干米粉镉含量均值为73μg/kg,超标率为5.5%。将广东省分为粤北、珠三角北、珠三角西南、珠三角东南、粤西、粤西南、粤东(客家地区)、粤东南(潮汕地区)8个区域进行比较,结果显示粤北地区市售大米及干米粉镉含量较高,均值为122μg/kg,超标率为12.5%。结论广东省8个区域市售大米及米制品镉含量有一定超标情况,其中粤北地区超标较明显,建议进一步开展专项调查研究,分析其来源及程度,为进一步开展镉暴露风险评估提供依据。     

2018—2020年北京市售蟹类镉含量调查及评价

目的 抽测2018—2020年北京市售蟹类中镉含量并进行评价,为蟹类的质量安全性评价提供基础数据。方法 采用随机采样的方法, 采集北京市售常见蟹类, 采用原子吸收光谱法对蟹中的镉含量进行检测;采用靶标危害系数法(Target hazard quotients, THQ)评估人体每日通过蟹类摄入重金属所带来的健康风险。结果 2018—2020年共采集蟹类样品83份, 重金属镉含量平均值为0.647 mg/kg。从蟹类的生长环境来看,淡水蟹重金属镉含量范围为0.043～0.620 mg/kg,平均值为0.183 mg/kg;海水蟹重金属镉含量范围为0.033～3.200 mg/kg,平均值为1.070 mg/kg;3年间蟹类中镉超标率差异具有统计学意义(P<0.05)。儿童、成人摄入蟹类中重金属的THQ值和总THQ值依次递减。不同年龄人群膳食摄入蟹类中镉的THQ值均＜1。结论 通过连续3年的系统性调查,本次采集的2018—2020年北京市售蟹类中存在一定的镉残留,其中海水蟹中镉含量超标现象较多,需加强监测;由于蟹类的食用具有季节性,普通人群摄入量较少,膳食风险相对较低。     

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.     

Sweetness and aroma perceptions in dairy desserts varying in sucrose and aroma levels and in textural agent

Sweetness–aroma interactions were investigated in model dairy desserts varying in sucrose concentration, aroma concentration and in textural characteristics using different textural agents (κ-, ι-, λ-carrageenans and an equal-mix of the three). Overall intensities of sweetness and aroma perceptions were evaluated by sensory analysis and apparent partition coefficients of aroma compounds were measured by static headspace—GC.Sweetness–aroma interaction was characterised by a non-reciprocal relationship. Concentration of aroma had no impact on sweetness intensity, whatever be the sucrose concentration or textural characteristics of desserts, whereas varying texture or sucrose concentration modified aroma intensity. However, effects on aroma assessment were effective only when aroma concentration was the highest. In this condition, use of λ-carrageenan or increasing sucrose concentration from 25 to 50 g kg⁻¹ enhanced aroma intensity, but no extra enhancement was observed when sucrose concentration was 100 g kg⁻¹. As the air–dessert partition coefficient remained constant, impact of textural characteristics and sweetness variation on aroma perception did not result from physico-chemical interaction.     

Aluminium and fluoride in hospital daily diets and in teas

The levels of aluminium and fluoride have been determined in hospital daily diets including breakfast, dinner and supper, as well as in black teas and herbal teas purchased from the local market. In tea, aluminium was determined directly in a sample solution by atomic absorption spectroscopy using nitrous oxide and an acetylene flame. For analysis of the hospital diet, samples containing lower levels of aluminium were analysed using a spectrophotometric method which measured aluminium in the form of a 8-hydroxyquinoline complex. Decomposition of the samples was achieved using a mixture of concentrated acids [nitric (HNO₃), perchloric (HClO₄) and sulphuric (H₂SO₄)] in platinum dishes. Fluoride was assayed by spectrophotometry using a microdiffusion procedure with a mixture of concentrated HClO₄ and silver sulphate, trace amounts of the released fluoride [as hydrogen fluoride (HF)] were trapped on the alkaline surface of a Petri dish and then determined in the form of an alizarin-fluoride complex. The mean level of aluminium found in hospital daily diets amounted to 21.3±12.3 mg and the mean level of fluoride was 1.38±1.12 mg per adult person. In the 16 samples of commercially available brands of black teas, the levels of aluminium and fluroide ranged from 445 to 1552 ppm (mean=897±264 ppm) and from 30 to 340 ppm (mean 141±85 ppm), respectively. In six herbal teas, the mean levels of aluminium and fluoride were lower, and amounted to 218.9±150.7 ppm and 6.0±6.9 ppm, respectively. This study has shown that concern about a high intake of aluminium and fluoride from these foods is unfounded.     

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。     

芝麻饼粕及其在烟草上应用研究现状

概述了芝麻饼粕的有效营养成分及其作为有机肥的加工方法,介绍了芝麻饼粕在烟草生产上的应用效果。并就进一步促进芝麻饼粕在烟草上的应用提出了建议,以期为烟叶生产过程中科学使用芝麻饼粕提供参考资料。     

Characterization of limestones and their effects in vitro and in vivo in dairy cattle

Capacities of limestones of differing particle size to neutralize acid in vitro and to modify pH and utilization of feedstuffs in vivo were compared. Acid neutralization during pH-stat titrations was faster for fine than for coarse limestone, and mixed microbial cultures were more resistant to pH change when they contained fine calcium carbonate. Diets containing 25:75 corn silage to concentrates and .95% calcium from either coarse or fine limestone were fed to rumen-fistulated heifers. Total ruminal volatile fatty acid concentrations were higher for the fine limestone treatment. Ruminal volumes, dry matter disappearance, and ruminal fluid pH and dilution rate did not differ between fine and coarse limestone treatments. Ruminal fluid volume, osmolality, ratios of acetate to propionate, and concentrations of total volatile fatty acids were unaffected in rumen-fistulated Holstein cows fed 60:40 corn silage to concentrates and either .5% calcium (control) or 1.0% calcium from either coarse or fine limestone. Ruminal pH increased .07 to .10 units with limestone supplementation. Ruminal fluid dilution and particulate turnover rates were slower for the coarse limestone than the control treatment. Differences between coarse and fine limestones in vitro were observed under some conditions in vivo, but they were not consistent.     

Flavour and vitamin stability in pasteurized milk in polyethylene-coated cartons and in polyethylene bottles

Commercially pasteurized, non-homogenized full cream milk in 2-pt white polyethylene (PE)-coated cartons overprinted with blue, and in 4-pt PE bottles was stored for 4 d in the dark or under white fluorescent light of 4000 1x, at a temperature of 7°C. The flavour of milks kept in the dark remained good, but exposure to light resulted in early off-flavour development: cartoned milk was disliked by a flavour panel after about 17.5 h exposure and milk in the PE bottles after 9 h. Vitamins A and B₂ were stable in the milk during 4 d storage in the dark in both bottles and cartons, and in cartons exposed to light. In the bottled milks, light-induced losses of these vitamins after 4 d were, respectively, 15% and 35%. but there was little or no loss before the development of light-induced flavour. Loss of total vitamin C by day 4 was about 50% in the dark, irrespective of container. In the cartons exposed to light, 66% of the vitamin C was lost, while virtually none remained in the exposed, bottled milk. There was also a markedly greater loss of vitamin C in the bottled milk than in the cartoned milk at the time the flavour became unacceptable. The dissolved O₂ concentration dropped considerably in the bottled milk exposed to light, but only marginally in the cartons. There were small increases in dissolved O₂ in the dark in both types of container.     

开封市畜禽沙门菌污染状况及血清学鉴定分析

了解开封市畜禽肉中沙门菌的污染状况及血清学分布,为沙门菌引起的食源性疾病的防控提供依据。方法 依据GB 4789.4—2010《中华人民共和国国家标准食品卫生微生物学检验方法》和2011年国家食源性疾病监测网监测方案,定期对开封市畜禽养殖场和屠宰场进行随机采样监测。结果 在691份样品中,沙门菌检出率为35.9%(248/691);分离出沙门菌253株,有17个血清型。结论 开封市生鸡肉和生猪肉不同程度受到沙门菌的污染,以生鸡肉污染最严重。应加强禽畜类养殖、屠宰加工等过程的卫生监管,减少食源性疾病的发生。     

Heavy metals in vegetables grown in The Netherlands and in domestic and imported fruits

The contents of cadmium, lead mercury, copper, manganese and zinc in 242 samples of 37 different species of domestic and imported fruits have been determined. Also contents of the same heavy metals, except mercury, have been determined in 205 samples of 7 species of domestic vegetables (lettuce, spinach, endive, beetroots, onions, celeriac and Swedish turnips). The median contents (in mg/kg fresh mass of the edible part) found for fruits are: Cd 0.002; Pb 0.017; Hg 0.002; Cu 0.61; Mn 0.52 and Zn 0.99. In the vegetables median levels have been found (mg/kg) of 0.009-0.073 for Cd, 0.01-0.03 for Pb, less than 0.2-0.3 for Cu, 0.69-1.41 for Mn and 0.95-5.5 for Zn. The contribution of fruits to the tolerable daily intakes of Cd, Pb and Hg is, for an average consumption pattern, less than 1%. On the other hand, the contribution to the recommended amounts of the essential elements Cu, Mn, and Zn is no more than 1%-3%. From the vegetables an average portion of spinach contains 19% and 2.6% of the tolerable daily amounts of Cd and Pb, respectively. For the other species of vegetables these figures are less than 5% for Cd (except for endive, 6.8%) and for lead less than 1%. Spinach contributes considerably to the need for Cu, Mn and Zn, in general more than 10% of the recommended daily amounts. The other species of vegetables contribute only from less than 1% to less than few percents.