Physicochemical and microbiological characteristics and mineral content of herby cacik,a traditional Turkish dairy product

Changes in the physicochemical properties, mineral and heavy metal content and microbial flora of cacik samples were studied over a storage period of 30 d. The analysis results were in the ranges as follows: dry matter content 16.45–20.76%, fat 1.45–4.30%, protein 8.14–13.87%, total ash 0.96–4.19%, salt 0.25–3.15%. There were significant differences in dry matter, fat, salt, protein and ash content of the cacik samples (P < 0.05). There were significant differences in Ca, P, Na, Mg, Cu, Fe, Zn and Mn content of the cacik samples (P < 0.05). Total aerobic mesophilic bacteria (TAMB) and enterococci reached levels above 10⁴ and 10³ CFU g^?1, respectively. Coliforms and Staphylococcus aureus were not detected in any of the cacik samples during the storage period. Lactic acid bacteria (LAB) on MRS and M17 agars were the dominant bacteria. The cacik samples had LAB counts up to 10^4.4 CFU g^?1. Copyright © 2005 Society of Chemical Industry     

乳及乳制品中矿物质元素检测方法的研究进展

乳及乳制品中矿物质元素的种类和含量是评价其营养质量的关键指标,选择出高效、灵敏、快捷的矿物质元素检测方法,在乳及乳制品的科研、生产、贸易等方面显得尤为重要。文章首先讨论乳及乳制品中矿物质元素检测的前处理方法,然后比较乳及乳制品中矿物质元素的检测方法,包括火焰原子吸收光谱法、石墨炉原子吸收光谱法、氢化物原子吸收光谱法、原子荧光光谱法、原子发射光谱法、电感耦合等离子质谱法、免疫分析法、中子活化分析法、伏安溶出法、酶抑制法等方法,最后总结各种方法的优缺点,旨在为乳及乳制品中矿物质元素检测方法的应用、研究和发展提供参考。     

A survey of selected heavy metal concentrations in Wisconsin dairy feeds

Heavy metals such as zinc (Zn), copper (Cu), chromium (Cr), arsenic (As), cadmium (Cd), and lead (Pb) are potential bioaccumulative toxins of the dairy production system. The heavy metal content of dairy feeds, however, remains poorly documented, particularly in the United States. This survey determined the heavy metal content of 203 typical dairy ration components sampled from 54 dairy farms in Wisconsin. Lowest heavy metal concentrations were found in homegrown alfalfa (Medicago sativa L.) hay and haylage, and corn (Zea mays L.) grain and silage. Highest metal concentrations were found in purchased feeds, particularly mineral supplements, and to a lesser extent corn- or soybean-based concentrates. Zinc and Cu were found at the highest concentration in complete dairy (total mixed and aggregated component) rations and reflected the deliberate addition of these metals to meet animal nutrient requirements although more than half the farms fed Cu and Zn above US recommended levels. Concentrations of Cr, As, Cd, and Pb were present in much lower concentrations and decreased in the order Cr > As > Pb > Cd. No complete Wisconsin dairy ration contained heavy metal concentrations above US maximum acceptable concentrations and would be unlikely to induce any toxic effects in dairy cattle. Concentrations of Cd in complete dairy rations were closest to US maximum acceptable concentrations, suggesting the greatest potential long-term risk to exceed US maximum acceptable concentrations if whole farm levels of Cd were to increase in the future. With the exception of Pb, the main sources of Zn, Cu, Cr, As, and Cd in the complete dairy feed ration originated from imported feed. The continued importation of heavy metals in dairy feed is likely to be associated with accumulation of these metals in soils where manure is applied. Although the cycling of many heavy metals through the dairy food chain will be limited by factors such as a soil's cation exchange capacity, pH, salinity, and phytotoxicity of the metal, these may be less limiting for Cd. It is important that sources of Cd in the dairy system are identified and minimized to prevent problems associated with Cd accumulation in the dairy soil system arising over the long-term.     

光谱技术在乳及乳制品研究中的应用进展

文章阐述了光谱技术在乳及乳制品掺假和掺伪检测、营养成分检测、抗生素检测、微生物污染检测,乳及乳制品种类的鉴定等方面的应用。综述了近红外光谱、拉曼光谱、高光谱成像技术在乳及乳制品品质检测和安全评定上的重要应用和研究进展,指出多种技术联合应用是未来研究的趋势。     

激光诱导击穿光谱在乳制品质量检测中的应用

乳制品是人体健康必需营养的重要来源之一,因此保证乳制品的质量和安全至关重要。作为一种新型的激光烧蚀原子发射光谱技术,激光诱导击穿光谱已经在乳制品的定性和定量分析方面展现出了巨大的应用潜力。本文简要介绍了激光诱导击穿光谱的检测原理,综述了激光诱导击穿光谱在乳制品中矿物质元素、重金属元素、脂肪和蛋白质含量,以及牛奶掺假物检测方面的最新研究进展。最后,探讨了激光诱导击穿光谱在乳制品质量检测方面存在的问题并对其发展趋势进行了展望。     

增强质量意识全面实施安全性乳与乳制品生产体系

根据发达国家食品生产的发展趋势，结合我国入世形势和发展需要，论述了安全性乳与乳制品的重要性，评价及其不安全因素的来源，提出在乳制品生产过程中建立完善的安全控制体系。     

如何面对乳制品贸易全球自由化

简述了入世后乳与乳制品行业应修订、制订产品高标准以适应市场新的挑战，并提出目前存在的产品质量问题。     

粮食重金属快速检测产品性能评价与分析

通过对10个不同品牌的粮食重金属快速检测产品进行适用性评价研究,了解市面上主要重金属快速检测产品的准确度、精密度及实际应用性能,采用“三三七”原则,分别对大米中铅镉元素进行了统计学分析。结果表明,10个品牌的粮食重金属快速检测产品对大米中镉元素的回收率基本满意,测定结果与样品标准值无显著性差异（P＞0.5）,而大米中铅元素检测不同品牌质量不一,部分品牌测定结果与样品标准值存在显著性差异（P＜0.5）,其中1个品牌数据离群,判定为不合格。10个品牌中有3个品牌产品稳定性较差,受人员操作影响较大。10个品牌均可在40 min内完成一个批次检测,检测时间短,操作简单,价格合理。综合评价指标显示目前市面上主要的粮食重金属快速检测产品仍存在一定的性能差异,需要改进。     

农用地土壤重金属污染引发的农产品质量安全问题及对策

我国农用地土壤重金属污染现象严重,由此引发了受污染土地产出农产品的安全风险问题。重金属污染物通过大气沉降、污水灌溉、固体废弃物的溶解而进入土壤,通过生物链在人体内富集,威胁人类的生命健康。本文总结了我国立法构建了农用地土壤重金属污染和农产品食品安全2个方面的监管体系,确立了环境、农业、质检等多个部门的监管职责,指出了环境与健康综合监管缺失,行政部门协调性不足,监测手段操作性差,公众监督意识低等问题,提出建立环境与健康风险评价,从定性分析转向定量评估;协调职能部门,建立农产品跟踪回溯制度;采用操作性强的监测手段;同时在法律、资金、技术、意识等方面作出配套安排等应对策略,以期为农产品质量安全的有效监管提供参考。     

多措并举, 把好出口乳品质量关

随着“三聚氰胺”阴影的逐渐散去和乳制品消费市场的逐渐回暖, 如何做好出口乳品的检验检疫工作和质量安全监督管理工作是对监管部门提出的一个严峻挑战。 本文分析了出口乳品受阻对本省乳品生产企业产生的不利的影响,为进一步提高出口乳品的管理水平、确保出口乳品安全, 提出了“风险分析等级评定、生产过程监管、提升企业自检自控能力、加强乳品防护措施、电子监管和企业自身管理的融合、产品安全指标监控”等6项举措。     

功能性乳制品及其相关开发途径

功能性乳制品是日益苛求食品安全的人们对营养品的自然追求,其需求量必将随着人们生活水平的提高而逐渐增加。西方发达国家早已青睐功能性乳制品的开发,并着手加以研究并得以快速的发展,但中国无疑尚处在开发的初始期。文章对什么是"功能性乳制品"进行界定,对其概念做出科学的诠释,探讨开发功能性乳制品的基本途径,研究功能性乳制品的生产现状和它生产的主要产品及开发中所存在的一些问题,对功能性乳制品发展的前景做出展望。     

乳及乳制品中抗寄生虫药检测研究进展

抗寄生虫药是牛羊等产奶动物养殖过程中必不可少的投入品。这些药物经牛羊吸收代谢后, 容易残留在牛羊奶及其他动物组织中, 给消费者造成安全隐患。我国食品安全国家标准规定了牛羊奶中21种抗寄生虫药的最大残留限量值, 科研工作者们也建立了多种检测方法。本文对2018~2023年牛羊奶中抗寄生虫药的检测方法进行综述, 简要对比电化学传感器法、表面增强拉曼光谱法、胶体金免疫试纸条法、液相色谱-质谱法、液相色谱-高分辨质谱法的优缺点, 并对抗寄生虫药检测方法的发展方向进行了讨论和展望, 为乳及乳制品中抗寄生虫药的定性筛查和定量检测提供技术参考。     

乳制品中乳酮糖的测定

采用高效液相色谱法测定乳制品中的乳酮糖。该方法简单易行,应用示差折光检测器。最低检测限为1.82×10-7g,变异系数（CV％）为1.74,回收率为94.0％～98.5％。     

基于最优最劣和熵值法的肉制品中重金属污染程度综合评价模型

提出一种基于最优最劣和熵值法的肉制品中重金属污染综合评价模型,该方法首先从毒性、含量2个方面构建评价体系,然后用最优最劣法评价各类肉制品的重金属污染程度,用熵值法对各地区肉制品中重金属污染程度进行综合评价.以某省5个城市4类肉制品重金属检测数据为例进行案例研究,对4类肉制品重金属污染程度排序发现,按内梅罗指数法和超标率...     

四川省茶叶中重金属与矿质元素含量分布特征

目的 研究四川省茶叶中重金属与矿质元素的分布特征。方法 收集四川省的242批茶叶样品,通过电感耦合等离子体质谱法测定分析茶叶中4种重金属元素和14种矿质元素。结果 四川省242批茶叶中,重金属的含量大小表现为铬（Cr）>铅（Pb）>砷（As）>镉（Cd）,变异系数大小关系为Pb>Cr>As>Cd;矿质元素含量大小表现为锡（Sn）>钠（Na）>钼（Mo）>钒（V）>铝（Al）>铁（Fe）>钴（Co）>铜（Cu）>锰（Mn）>镍（Ni）>锌（Zn）>钙（Ca）>钾（K）>镁（Mg）,平均变异系数41.8%～57.1%;研究发现Zn、V、Ni元素是四川省242批茶叶中的特征元素,同时经矿质元素含量综合得分计算,达州、眉山、甘孜、广元、巴中、自贡、乐山地区的茶叶对矿质元素的富集能力较强。结论 本研究可作为四川省茶叶中18种元素含量的本底值参考,为相关企业、监管机构、茶叶研究者提供数据参考。     

乳与乳制品中总砷测定的不同前处理方法比较

目的比较不同前处理方法的处理效果,选择适合乳与乳制品中总砷测定的前处理方法。方法分别采用湿法消解、干法灰化、微波消解对乳与乳制品样品进行前处理,利用氢化物原子荧光法测定总砷含量。结果 3种前处理方式的检测结果均满足方法学要求,湿法消解、干法灰化和微波消解的回收率分别为81.7%～86.5%,90.0%～94.4%和90.8%～95.6%,精密度分别为8.84%～9.80%,3.22%～4.37%和3.18%～4.82%;检出限分别为0.0042、0.00068、0.0028mg/kg;微波消解法处理的质控样品结果更接近于标准值。结论微波消解法操作简便、准确性好,适合乳制品企业批量产品检测。     

核磁共振技术在乳制品研究中的应用

在简述NMR的基本原理之上，综合国内外的研究成果，重点介绍了NMR技术在乳制品中的脂肪、水分和蛋白质研究中的应用．并在测定脂肪固液比、脂肪结晶温度、持水量、水分结合状态、蛋白质变性、蛋白质聚集状态等方面做了详细的阐述，列举了丰富大量的实例．最后展望了NMR在这个领域的应用前景。     

Effect of trace mineral source on lactation performance, claw integrity, and fertility of dairy cattle

Two hundred fifty multiparous and primiparous cows were assigned to a study at approximately 70 d prepartum to determine the effect of trace mineral source on lactation performance, claw integrity, and fertility. Cows received treatments from 3 wk prepartum through wk 35 postpartum. Treatments consisted of 1) all supplemental Zn, Mn, Cu, and Co provided in sulfate form (Sulfate) and 2) 360 mg of Zn, 200 mg of Mn, 125 mg of Cu, and 12 mg of Co supplied daily by Sulfate minerals replaced with similar amounts of minerals supplied by Availa-4 (CTM). Individuals involved with daily animal care or data recording, or both, were blinded to treatment assignments. Cows from all treatments were housed in common pens, and treatments were dispensed to cows via a computerized feeder. All claws of cows were examined before treatment administration and at 16 and 36 wk postpartum by personnel trained in identifying claw lesions. Cows fed the CTM diet tended to produce more milk and energy-corrected milk than cows fed the Sulfate diet. Cows fed the CTM diet also produced more milk protein and solids (fat + protein) than cows fed the Sulfate diet. Replacing Sulfate minerals with those supplied by CTM decreased incidence of sole ulcers at wk 36 postpartum and tended to decrease incidence of interdigital dermatitis at wk 16 and 36 postpartum. Severity of heel erosion tended to be less for cows fed CTM than cows receiving the Sulfate diet. Despite first service conception rates tending to be greater for cows fed the Sulfate diet, there was no effect of treatment on rate of conception. A greater percentage of cows fed the Sulfate diet tended to be culled from the herd before wk 36 postpartum than cows fed the CTM diet. Replacing Sulfate minerals with CTM resulted in improved lactation performance and claw integrity.     

乳制品中明串珠菌的分离鉴定及其生物学特性研究

对内蒙古自治区呼伦贝尔市牧区98个乳样中的明串珠菌进行了分离及生物学特性研究。共分离到明串珠菌3株，分别属于乳明串珠菌(EW21)，肠膜明串珠菌葡聚糖亚种(EW24—2)和肠膜明串珠菌肠膜亚种(CB8—1)。它们均可在pH=4．8的环境中生长，且菌株EW24—2和CB8—1可利用蔗糖生成葡聚糖。