共查询到20条相似文献，搜索用时 62 毫秒
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酒精阳性乳是指在20cc温度下，用68％～70％酒精与等量牛乳混合而产生微细颗粒或絮状凝块的牛乳。根据酒精阳性牛乳酸度的差异，可将其分为高酸度酒精阳性乳和低酸度酒精阳性乳两种。高酸度酒精阳性乳其滴定酸度在18。T以上，发生原因是因牛乳在收藏、运输等过程中，由于卫生消毒不严，未及时冷却，乳中微生物迅速繁殖，乳糖分解为乳酸，致使酸度增加所致。这种乳加热后凝固，其实质是发酵变质牛奶。低酸度酒精阳性乳是指酸度在11—18°T之间，加等量70％酒精混合后出现凝集的牛乳。这类牛奶的颜色、外观往往无肉眼可见变化，加热煮沸不凝固，煮沸后加酒精不再出现絮状物。 相似文献
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奶牛酒精阳性乳的临床调查分析 总被引：4，自引：0，他引：4
酒精阳性乳是指用68％或70％酒精(生产上常用72％酒精)与等量牛乳混合而产生微细颗粒或絮状凝块的牛乳。根据酒精阳性牛乳酸度的差异．可将其分为高酸度酒精阳性乳和低酸度酒精阳性乳两种。高酸度酒精阳性乳其发生原因是因牛乳在收藏、运输等过程中，由于卫生消毒不严．未及时冷却．乳中微生物迅速繁 相似文献
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在乳品厂收集、加工牛乳过程中,酒精试验常用来作为检验牛乳品质优劣的一个指标,同时也作为评定牛乳酸度变化的依据。凡是酒精反应呈阳性的牛乳,皆按不合格乳处理,因此,有相当数量的酒精阳性乳被拒收或降价收购,这给奶牛经营者造成了较大的经济损失。本文主要对酒精阳性乳的产生原因进行分析,并提出相应的防治措施,以期为牛乳生产提供参考。1酒精阳性乳的分类根据酒精阳性乳的酸度差异,可将其分为高酸度酒精阳性乳和低酸度酒精阳性乳两类。高酸度酒精阳性乳是指滴定酸度在18°T以上,加入等体积的70%酒精溶液出现凝固现象的牛乳,其产生原因… 相似文献
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酒精阳性乳的产生、防治及利用 总被引：2，自引：0，他引：2
乳品厂常用酒精试验作为检验牛乳品质优劣的一个指标,同时也用来作为评定牛乳酸度变化的依据。取一定量68％～72％的酒精于试管内,加入等量的牛乳混合振摇,出现白色颗粒或絮状物的为阳性,即为酒精阳性乳。市场上鲜牛奶的酸度一般要求不超过20°T,对制造炼乳的原料一般要求不超过18°T。因此,凡属酒精阳性乳,不论其酸度高低、加热凝固与否,皆按不合格牛乳品处理的做法是不妥的。1 酒精阳性乳的种类 根据牛奶酸度不同可分为高酸度酒精阳性乳和低酸度酒精阳性乳。酸度在18～20°T以上的为高酸度酒精阳性乳,加热后凝固,是发酵变质 相似文献
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酒精阳性乳也称为“酸奶”,在常温20℃下与70%的酒精混合后能发生凝结现象的牛乳都称为酒精阳性乳。可分为高酸度和低酸度酒精阳性乳两种。 高酸度酒精阳性乳是与70%的酒精混合时能发生凝结现象的乳。主要是在挤乳过程中,由于挤乳机管道、挤乳罐消毒不严,挤乳的环境不良,牛乳的保管、运输不当或未及时冷却等因素,使细菌繁殖生长,从而乳糖分解成乳酸,乳酸升高,蛋白变性所致。 低酸度酒精阳性乳是指刚从乳房中挤出的新鲜牛奶乳酸含量不高,但与70%的酒精混合后能发生凝结现象的牛乳。奶牛不表现任何临床症状,所生产的乳,乳品加工企业拒绝收… 相似文献
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低酸度酒精阳性乳的防制 总被引：1，自引：0，他引：1
低酸度酒精阳性乳 ,是指酸度在 16°～ 18°T之间 ,用 72 %酒精与等量牛乳混合 ,产生细小絮状、凝块的乳。这种乳的酸度正常 ,但酒精试验呈阳性 ,所以称作低酸度酒精阳性乳。多年来 ,酒精试验已成为乳品厂检验牛乳品质好坏的一个重要指标 ,常用来作为评定牛乳酸度变化的依据。凡属酒精阳性乳 ,不论酸度高低 ,加热凝固与否 ,乳品厂均按不合格处理 ,致使大批质量稍差、但尚能利用的新鲜牛乳被废弃 ,使乳业蒙受很大的经济损失。目前对低酸度酒精阳性乳病牛的发病机理尚不清楚 ,也无有效治疗方法 ,随着我国奶牛业的快速发展 ,研究和解决这一技… 相似文献
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《畜牧兽医科技信息》2016,(11)
正玉米发酵型饮料多由新鲜甜糯玉米进行乳酸菌发酵而生产的,本试验采用普通粮食用黄玉米为原料,在模拟自然发酵基础上,优化规模化生产的工艺技术,筛选规模化生产发酵剂的菌种及发酵助剂(酶),生产适合大众口味的混浊型饮料。1材料与方法1.1材料市售普通玉米籽粒(玉米面亦可)。1.2方法测定自然发酵酸度,调节人工发酵条件,使乳酸菌种发酵达到自然发酵酸度。1.3检测方法总酸度测定:Na OH滴定法;有效酸度测定: 相似文献
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魏静 《四川畜牧兽医学院学报》2009,(4):28-32
在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。 相似文献
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本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。 相似文献
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以国际标准强毒Ｒ株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离ＭＧ,并收集感染鸡所产蛋分离ＭＧ。结果表明,人工感染４８小时后上、下呼吸道及肺已被全面感染,９６小时气囊已被感染,１２０小时输卵管已能分离到ＭＧ,卵巢始终分离不到ＭＧ。人工感染鸡自１４４小时便能在其所产蛋中分离出ＭＧ。药物治疗能在７２小时内消除感染,油乳剂苗则需２４天后逐渐降低蛋内ＭＧ分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内ＭＧ,但以研制的种蛋浸泡剂药浴效果为最好。 相似文献
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REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air. 相似文献
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Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF
Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo. 相似文献