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1.
高压脉冲电场非热杀菌技术对原料奶的预处理   总被引:2,自引:0,他引:2  
针对国内原料奶质量较低这一问题,运用高压脉冲电场非热杀菌技术对原料奶进行预处理。发现原料奶的细菌总数随电场强度、脉冲数、初始温度的增加而降低,随流速的增加而升高。当出口温度为常温20℃.电场强度为50kV/cm,脉冲频率为1000Hz,流速为20nL/min时,能使其菌落总数降低2.6个数量级,从四级原料奶提升至一级原料奶,且不改变其营养结构和风味。  相似文献   

2.
《畜牧与兽医》2017,(2):103-106
为提高原料乳的营养价值及卫生质量,跟踪采集2015年1月至12月长江下游地区12家小规模奶牛场的原料乳混合样,研究不同月份、不同牧场对原料乳中乳蛋白率及细菌总数的变化规律。结果显示:不同月份对乳蛋白率、细菌总数的影响明显;不同牧场的乳蛋白率之间差异显著(P<0.05),而细菌总数之间差异不显著(P>0.05)。提示:在实际生产中,可根据乳蛋白的变化规律,调整不同月份、不同牧场的日粮结构,提高原料乳中蛋白质含量,满足人类对奶产品质量不断变化的需求;同时,也可根据细菌总数的变化规律,规范牧场的生产操作,降低原料乳中的细菌总数,提高原料乳的卫生质量。  相似文献   

3.
贮存温度对原料奶细菌增殖的影响   总被引:1,自引:0,他引:1  
本文对奶牛养殖小区机械化挤奶后的原料乳细菌增殖情况进行了研究。报道了贮存温度和贮存时间对挤奶后的原料乳细菌总数、pH值和酸度的影响。  相似文献   

4.
试验比较原料乳中三种菌落总数的测定方法。分别采用国家标准GB/T4789.2—2010、世界乳品联合会国际标准IDF100A:1987和美国食品与药品监督局FDABAM—2001标准中三种菌落总数的检测方法对原料乳中菌落总数进行测定比较分析。结果表明,3种检测方法之间存在显著性差异,IDF100A:1987的检出率最高,菌落易于分辨,但检验周期较长,不利于快速检测;在检测原料乳上,FDABAM—2001优于GB/T4789.2—2010,其共同优点为方法简单,检验周期短。  相似文献   

5.
目的 生鲜乳的冷却是牛奶安全生产的重要环节,比较不同制冷模式对生鲜乳品质的影响非常重要。方法 本项目对比了速冷和直冷两种生鲜乳制冷模式对生鲜乳冷却时间、温度、酸度、菌落总数的影响,以期为更好地利用和推广生鲜乳速冷技术提供参考。结果 速冷模式可以在1~3 min内将生鲜乳温度冷却至4 ℃,效率远高于常规直冷模式,综合经济效益显著;在奶罐温度保持上,在4 h内速冷模式下,生鲜乳温度(5.12 ℃)、酸度(13.47 OT)、菌落总数(1.58 CFU/mL)极显著优于直冷模式的温度(5.55 ℃)、酸度(12.92 OT)、菌落总数(4.06 CFU/mL);对温度、酸度、菌落总数双变量相关分析结果表明,在直冷模式下,温度与酸度、菌落总数相关性不显著;在速冷模式下,温度与酸度呈显著的负相关性,与菌落总数无显著相关性。结论 采用速冷模式可有效降低菌落总数,减少微生物繁殖,保障生鲜乳的质量,综合效益显著,为传统牧场奶厅改造,保障优质乳生产提供了可行性方案。  相似文献   

6.
本文对手工挤奶方式在挤奶过程中、挤奶后储存阶段原料乳细菌总数的变化情况进行了研究。分析了细菌总数的变化趋势及原因,提出了在挤奶过程中熏以及挤奶后储存阶段控制原料乳细菌总数的方法。  相似文献   

7.
以2012年和2013年上海市生鲜乳中菌落总数的变化和特征为研究对象,对2年的菌落总数的数量变化进行分析,并考察蛋白质含量、脂肪含量、平均温度对生鲜乳中菌落总数的影响。结果表明:生鲜乳菌落总数呈季节性差异,但不同年份的菌落总数质量性状差异也较大;蛋白质含量、脂肪含量、平均温度对生鲜乳中菌落总数都有影响,温度影响最显著。  相似文献   

8.
通过酒精试验及测定酸度确定原料乳是否变质;用乳脂成分检测仪测定原料乳中常见指标,如脂肪、蛋白质、总固形物(TS)、非脂乳固体(SNF)等,以确定原料乳的营养状况;采用BactoScan 8000s测定原料乳中的细菌总数并分析原料乳的品质.  相似文献   

9.
为了验证深海1号和多肽菌素产品在反刍动物养殖中具有降低奶牛的体细胞数和牛奶中的菌落总数,增加牛奶中的蛋白质和脂肪含量的功效,本研究随机选取蒙荷牧场泌乳奶牛为试验对象,拌料添加深海1号和多肽菌素,饲喂试验全程后,奶牛的体细胞数整体下降并趋于稳定,乳房炎得到有效控制,且降低了生鲜乳中的菌落总数,增加了蛋白质和脂肪含量,一定程度上改善了生鲜乳的风味,提高了奶牛的生产、生长性能,为实现反刍动物的无抗化绿色、健康养殖奠定了基础。  相似文献   

10.
应用MATLAB图像处理技术评判原料乳细菌数的研究   总被引:3,自引:0,他引:3  
本文简要论述了MATLAB图像处理原理和方法以及原料乳自动分级系统的软硬件结构,重点研究了MATLAB图像域值化方法、图像面积提取技术以及图像均匀化处理和灰度值域处理方法在原料乳等级评判上的探索应用。实际验证,应用本系统对原料乳在线检测,细菌总数的识别率可达到95%以上,从而可以达到对原料乳快速分级的目的。  相似文献   

11.
1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.  相似文献   

12.
Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.  相似文献   

13.
Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.  相似文献   

14.
The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.  相似文献   

15.
The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.  相似文献   

16.
17.
An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.  相似文献   

18.
Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein  相似文献   

19.
正We are pleased to publish the second special issue on avian brood parasitism and to be responsible guest editors for the two special issues of Chinese Birds (Vol. 3, No. 4, 2012 and Vol. 4, No. 1, 2013), entitled "Avian Brood Parasitism - A Growing Research Area in Behavioral Ecology". The first issue was published in December 2012. The goal of the two special issues is to publish accumulated knowledge and some of the recent developments in  相似文献   

20.
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