牛乳中青霉素残留检测技术研究进展

牛乳中青霉素残留问题已引起食品安全管理部门和国际组织的广泛关注。介绍了检测牛乳中青霉素残留的3种方法:微生物检测法,免疫检测法,理化检测法。     

高效液相色谱-串联质谱法测定牛奶和奶粉中9种青霉素类药物残留量

建立一种检测牛奶和奶粉中9种青霉素类药物残留量的高效液相色谱-串联质谱方法。样品经乙腈-水提取,经HLB固相萃取柱净化,用高效液相色谱串联质谱检测,外标法定量。本方法的检出限,牛奶中氨苄西林、奈夫西林为1μg/kg,阿莫西林、哌拉西林、青霉素G、青霉素V、氯唑西林为2μg/kg,苯唑西林、双氯西林为4μg/kg;奶粉中氨苄西林、奈夫西林为8μg/kg,阿莫西林、哌拉西林、青霉素G、青霉素V、氯唑西林为16μg/kg,苯唑西林、双氯西林为32μg/kg。9种青霉素在1.0～50ng/mL范围呈良好线性,线性相关系数大于0.9888。牛奶的平均回收率为77.58%～97.77%,测定结果的相对标准偏差为4.24%～16.59%(n=10);奶粉的平均回收率在85.95%～96.78%之间,相对标准偏差为2.71%～13.41%(n=10)。该方法具有简便、快速、准确度高、检出限低的优点,适用于牛奶和奶粉中青霉素类抗生素的测定。     

固相萃取-高效液相色谱-串联质谱法测定牛乳和猪肉中5 种青霉素类抗生素

建立一种用固相萃取-高效液相色谱-串联质谱法检测牛乳和猪肉中苄星青霉素G、氨苄西林、苯唑西林、氯唑西林、双氯西林5 种青霉素类抗生素方法。样品经乙腈提取,Bond Elut C18固相萃取柱净化,用高效液相色谱-串联质谱检测,外标法定量。结果表明,本方法5 种青霉素在2.0～200 μg/L范围内呈良好线性关系,线性相关系数大于0.999;牛乳样品添加回收实验,回收率为85.2%～122.7%,相对标准偏差为3.43%～16.8%（n=6）;猪肉样品添加回收实验在50 μg/kg和100 μg/kg添加水平,除氨苄西林外,回收率在94.3%～116.4%,相对标准偏差为1.62%～5.09%（n=6）。方法定量限为1.0～2.0 μg/kg。该方法具有简便快捷、准确度高、定量限低的优点,适用于牛乳和猪肉中青霉素类抗生素的测定。     

UPLC-MS/MS测定牛奶中9种青霉素

建立超高效液相色谱-串联四极杆质谱多反应离子监测模式同时测定牛奶中9种青霉素类抗生素(包括羟氨苄青霉素、氨苄青霉素、邻氯青霉素、双氯青霉素、乙氧柰胺青霉素、苯唑青霉素、苄青霉素、苯氧甲基青霉素、甲氧苯基青霉素)残留量的检测方法。样品采用乙腈沉淀蛋白、脱脂后,过HLB小柱净化、富集。以0.01 mol/L乙酸铵水(甲酸调节p H 4.5)-乙腈梯度洗脱,经Agilent Eclipse plus C18色谱柱(2.1×100 mm,粒径1.8μm)分离后,采用MRM模式进行定量定性分析。结果:结果表明9种抗生素在0.1μg/L~100μg/L范围内线性关系良好,高中低浓度回收率在67.7%~92.8%,相对标准偏差(n=6)小于15%,各组分定量限为0.1μg/kg~4μg/kg。     

Effects of Dietary Crude Protein on Protein and Fat Deposition in Milk-Fed Veal Calves

Research on veal calf production has focused on maximizing lean tissue growth. Nevertheless, limited attention has been paid to the evolution of digestive and metabolic utilization of N and energy as calves get older, whereas age at slaughter increases. The objective of this study was to determine the effects of 4 concentrations of dietary crude protein (CP) content on protein and fat deposition and energy utilization in milk-fed calves at 3 stages of fattening using the balance technique combined with heat production measurements in a respiration chamber. At each stage, 16 Prim’Holstein male calves (mean body weight at each stage: 72, 136, and 212 kg) received 4 isocaloric diets with CP contents of 76, 88, 100, and 112% of a reference CP content fixed at 20% during the first stage and 19% during the 2 later stages. After 2 wk of adaptation to their respective diets and housing conditions, the calves were placed for 1 wk in an open-circuit respiration chamber for N and energy balance measurements (first 6 d) and measurement of the fasting heat production (last day). Measurements for a stage were performed over 2 periods of 4 successive weeks. There was no effect of dietary CP on digestibility during the 2 later stages, but the low-protein diet resulted in lower digestibility coefficients for dry matter, organic matter, gross energy, CP, and crude fat during the first stage. Endogenous fecal N was estimated as 2.5 g/kg of dry matter intake irrespective of stage, and metabolic urinary N was estimated at 0.07 g/kg of body weight^0.85 per day. Maximum N retention was 32.8, 40.5, and 44.0 g/d at stages 1, 2, and 3, respectively. The effect of protein intake on protein deposition was dependent on age of the calves, because the marginal efficiency of digestible protein utilization decreased from 64 to 18% as animals got older. Fat deposition decreased with increasing dietary CP content irrespective of stage. Total energy retention was not modified by dietary CP content. The composition of body weight gain was affected differently for each stage, because the protein content of body weight gain increased with increasing dietary CP content during the first stage, whereas it remained constant during the other 2 stages. Fat and energy content in body weight gain decreased with increasing dietary CP irrespective of stage. These results provide a basis for estimating protein requirement of veal calves according to a factorial approach.     

荷斯坦公犊牛与成年公牛不同部位牛肉营养成分检测

为针对不同月龄及不同部位牛肉开展营养品质评价分析研究,选取荷斯坦公犊牛与成年公牛(24月龄)不同部位牛肉进行能量、蛋白质、脂肪、碳水化合物、钠、铁、锌、灰分、水分及氨基酸含量的测定。结果表明:犊牛牛肉能量、脂肪、铁、锌含量(分别为(382.0±16.6)、(1.3±0.4)、(0.8±0.1)、(25.0±4.6)mg/100 g)均显著低于成年牛肉(分别为(880.0±463.0)、(14.5±14.1)、(1.7±0.7)、(47.0±14.8)mg/100 g),P值均小于0.01,而蛋白质和碳水化合物含量与成牛牛肉含量较为接近。犊牛牛肉必需氨基酸含量(394.3 mg/g pro)高于成牛(365.2 mg/g pro)。犊牛不同部位牛肉营养成分较为接近,而成牛不同部位间能量、脂肪及碳水化合物含量差异较大,其变异系数分别高达52.6%、97.2%、100.0%。不同月龄及成年牛不同部位牛肉的营养品质具有一定差异,不同人群应结合自身营养需求特点进行合理选择。     

饲喂大豆类代乳料对犊牛生长发育和日粮养分消化率的影响

研究饲喂含常规大豆蛋白代乳料对犊牛生长增重、小肠发育和日粮养分消化率的影响.结果表明:A、B组日粮的养分表观消化率和氮沉积率明显低于C组,其中粗蛋白质表观消化率和氮沉积率差异显著(P＜0.05);A、B组犊牛小肠发育不良,小肠绒毛高度差异极显著(P＜0.01),平均日增重仅为C组的48.28%和70.96%,说明去皮豆粕和全脂大豆不宜作为36日龄前的犊牛代乳料的蛋白质来源.     

核桃乳中掺大豆乳的鉴别研究

建立了一种用高效液相色谱法检测核桃乳中掺有大豆乳的方法。样品用甲醇超声提取20 min,料液比为1:9 （体积比）,在4000 r/min条件下离心20 min。使用Promosil C18（4.6 mm×150 mm,5 μm）色谱柱,以甲醇-水作流动相进行梯度洗脱,检测波长为258 nm。结果表明,通过对大豆异黄酮的检测,可以有效地鉴别核桃乳中是否掺有大豆乳;大豆苷和染料木苷的线性范围为0.3~200 μg/mL,大豆苷元和染料木素的线性范围0.1~150 μg/mL。线性相关系数在0.9968和1.0000之间,样品加标回收率为80.73~116.44%,相对标准偏差≤4.62% (n=5),检测限为0.03~0.1 μg/mL,该方法快速、灵敏、简便易行。     

动物源性食品中青霉素类药物残留检测

建立动物源食品中同时检测4?种青霉素类药物残留的高效液相色谱法。以水合氨苄青霉素为内标,样品经乙腈-水（10∶1,V/V）提取,HLB固相萃取小柱净化。采用C18色谱柱,以0.02?mol/L磷酸二氢钾溶液-乙腈为流动相,梯度洗脱分离目标化合物进行定量分析。青霉素G、苯唑西林、乙氧萘青霉素、双氯青霉素在0.01～2?μg/mL范围内线性良好,线性相关系数均大于0.999,检出限和定量限分别为3?μg/kg和10?μg/kg;回收率在69.9%～100.3%之间,精密度的相对标准偏差在1.58%～9.15%之间。该方法前处理简单、快速、准确、灵敏,可以满足实际检测分析的需要。用于猪、牛、羊、鸡、鱼等不同基质中青霉素类药物残留的检测,取得了满意的结果。     

液相色谱-串联三重四极杆质谱测定牛奶中的氯霉素残留量

建立牛奶中氯霉素残留的高效液相色谱-串联四极杆质谱联用测定方法。该方法经乙腈提取样品,以MGⅢ-C18柱(2.1×150 mm,1.8μm)分离,流动相为水溶液和乙腈(体积比为65∶35),电喷雾负离子MRM模式检测。该方法的检出限0.07μg/L,线性范围0.05μg/L~20.0μg/L,加标回收率98.5%～110.8%,相对标准偏差为3.57%。     

液相色谱-串联三重四极杆质谱测定牛奶中的红霉素残留

建立糕点中8种人工合成色素的高效液相色谱测定法.采用乙醇-氨(70:30,体积比)混合溶液作为提取剂,挥干乙醇,用4%甲酸水溶液中溶解,经HLB小柱净化后,采用高效液相色谱进行分析.该方法的检出限为1.0 mg/L,线性范围0.40 mg/L～50 mg/L,加标回收率86.9%～105.7%,相对标准偏差为1.09%～4.28%(n=4).     

超声波对牛奶中青霉素的分解作用研究

研究超声波、超声波与VC协同分解青霉素的效果,发现超声波与VC的协同作用可以增强分解青霉素的效果。在细胞粉碎机占空比60,输出功率60％,处理时间8min,VC浓度0．1％条件下,对牛奶中含有≤1．0单位的青霉素的分解效果最佳。     

生鲜牛乳中氟喹诺酮类药物残留的检测方法

在生鲜牛乳中莱克多巴胺的检测限为2μg/kg,在2μg/L～100μg/L添加浓度水平上回收率为60%～120%,本方法与仪器技术分析相比具有操作简便,快速,准确度和灵敏度高,样品加标率回收效果好,检出限低,试剂盒稳定性、重现性好等特点。     

Effects of Milk Solids Content on Consumption of Milk

Strong interest continues for higher solids-not-fat standards for whole, lowfat, and skim milk than those currently established by the Food and Drug Administration for milk in interstate commerce. This paper traces the implications of establishing new national fluid milk standards identical to the current high standards in California. The greatest change in product composition implied by the adoption of the California standards would be in lowfat milk, where the solids-not-fat standard would rise from 8.25 to 10.0%. Whole and skim milks’ composition would be less dramatically affected.Fortification costs are estimated at 3¢/.5 gal (1.89 L) for whole milk, about 5¢ for lowfat milks, and about 1.5¢ for skim milk. Retail prices are projected to rise 3 to 5% across the fluid product line. Assuming no change in consumer preferences, fluid milk sales are estimated to drop 1.2 to 5.1% nationwide upon adoption of the California solids standards (the percentage drop dependent upon the responsiveness of consumers to price changes for fluid milk). Total sales of solids-not-fat would increase 21 to 184 million lb (19.52 to 83.46 million kg) annually under higher solids standards, which is not enough to affect significantly the current supply-demand imbalance in the dairy industry.     

Effects of Feeding High Magnesium to Young Dairy Calves

Holstein bull calves were fed 1, 2, and 4% supplemental magnesium as magnesium oxide. The control diet contained .3% magnesium and consisted of ground corn, soybean meal, cottonseed hulls plus mineral, vitamin, and antibiotic supplements. Diarrhea was the most obvious effect of high intake of magnesium. The extent and intensity of the diarrhea was related closely to the dietary magnesium content. High (2 and 4%) magnesium reduced feed consumption and weight gains. Although there were traces of blood in feces, no abnormalities were observed at autopsy. Large tubular sections of mucus were voided in the feces with a greater prevalance among calves fed 2 and 4% supplemental magnesium. Magnesium in plasma rose sharply in response to the increased intake of magnesium. In calves receiving the 4% added magnesium, the plasma values were triple those of controls. When high magnesium was fed, magnesium increased much more in urine than in plasma. Within 1 wk after calves were returned to control diet, magnesium in urine and plasma declined to control.     

高效液相色谱法测定牛奶中林可霉素的残留量

研究建立牛奶中林可霉素残留量的高效液相色谱测定方法。样品用水相提取,离心分离,经C18固相萃取柱净化,在210nm波长下用二极管矩阵检测器检测。色谱柱为Agilent ZORBOX SBC18柱(4.6×250mm,5μm),以0.05mol/L硼砂溶液(用磷酸调节pH6.0)-甲醇(55:45,V/V)为流动相,流速1.0ml/min。林可霉素浓度在1.0～10.0μg/g范围内与峰面积呈良好的线性关系,平均回收率为82.9%～93.1%,变异系数为1.45%～4.58%,最低检测限为0.5μg/ml。本方法简便、快速、准确。     

中国居民奶及奶制品消费现状分析

为分析我国居民奶及奶制品的消费情况,指导合理消费奶及奶制品提供科学依据,作者使用2002年中国居民营养与健康状况调查中一年食物频率调查的数据,分别对55211名15岁及以上居民的鲜奶、奶粉、奶酪和酸奶的食用率、食用频率和食用量进行了分析。结果表明,我国15岁及以上居民奶及奶制品的食用率为23.7%,鲜奶、奶粉、奶酪和酸奶的食用率分别为17.4%、8.5%、3.2%和10.1%,食用频率为0.7次/周、0.2次/周、0.1次/周和0.2次/周,每人每天的食用量为20.6g、0.8g、0.7g和4.2g。奶及奶制品的食用率、食用频率和食用量均为城市高于农村,男性低于女性,15～17岁组和60岁～组较高,18～44岁和45～59岁较低。我国居民的奶及奶制品的消费水平较低,应指导人们科学、合理增加奶及奶制品的消费。