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1.
为了评估巴氏杀菌水牛奶在不同储存温度下的最佳储存时间及杀菌效果,对巴氏杀菌水牛奶在不同温度环境下储存不同时间段的微生物菌落总数及金黄色葡萄球菌菌落数的变化规律进行研究。结果表明,巴氏杀菌水牛奶在4℃环境中的最佳储存时间为0~60 h,在10℃环境中的最佳储存时间为0~48 h,而在20℃、30℃环境中分别只能储存20 h和8 h。在3天的储存期内,30℃环境中储存的巴氏杀菌水牛奶中微生物增长速度最快,在4℃环境中储存时微生物增长速度最慢,储存效果最好。同时经巴氏杀菌的水牛奶中均未检测出金黄色葡萄球菌。  相似文献   

2.
研究长保质期酸乳的均质及后杀菌过程对变性淀粉颗粒形态的影响.结果表明:随均质温度的升高,均质压力的增大,淀粉破碎逐渐增多,最佳均质温度60~63℃,均质压力15~20 MPa;超高温(ultra high temperature,UHT)管道压力能促进淀粉的进一步膨胀,随着管道压力的增大和回流次数的增加,淀粉颗粒逐渐增大甚至破裂,最大管道压力为7 bar;随着UHT杀菌温度的逐渐提高,淀粉破碎逐渐增多,最高杀菌温度为80℃.  相似文献   

3.
对经不同条件二次巴氏杀菌的长保质期酸乳的黏度、脱水收缩作用敏感性(susceptibility to syneresis,STS)和感官品质进行测定,将长保质期酸乳分别置于25、37℃条件下恒温贮藏,定期测定产品的霉菌、酵母菌数及菌落总数。结果表明:随着二次巴氏杀菌温度的升高,产品的黏度逐渐降低、STS逐渐增大;二次巴氏杀菌条件为60℃、30 s产品的喜好度最高,90℃、30 s杀菌产品的喜好度最低;本研究选择的二次巴氏杀菌条件能将残存的霉菌和酵母菌灭活,产品的菌落总数随着二次巴氏杀菌温度的升高而降低,且贮藏温度越高,产品越容易受到污染。综上所述,选择二次巴氏杀菌条件为70℃、30 s效果最佳。  相似文献   

4.
为了筛选出艾叶和黄柏两味对巴氏杆菌有抑菌活性的中药有效成分的最佳提取工艺,试验以中药提取物有效成分的浸膏得率和对巴氏杆菌的最小抑菌浓度(MIC)与最小杀菌浓度(MBC)为综合考察指标,以提取工艺中的料液比、提取次数、提取时间、乙醇浓度、提取温度为因素进行工艺优选。结果表明:艾叶有效成分的最佳提取条件为料液比1∶30,乙醇50%,提取温度70℃,每次提取2 h;黄柏有效成分的最佳提取条件为料液比1∶7,乙醇70%,提取次数3次,每次提取80 min。在该工艺下进行提取,中药有效成分浸膏得率可以得到最大化保障,对巴氏杆菌的MIC和MBC值均≤15.6 mg/m L。说明该工艺为最佳提取工艺。  相似文献   

5.
为研究新型消毒剂-卫克的杀菌效果,以含相同主要成分的卫可消毒剂为对照,采用悬液定量法,观察了卫克消毒剂对大肠杆菌的杀菌效果、抗有机物干扰杀菌效果及温度对其杀菌效果的影响.结果显示,卫克消毒剂1∶200稀释液在室温下作用2 min即可将大肠杆菌全部杀灭,杀菌效果不受有机物和温度影响;1∶400稀释液在室温下作用10 min杀菌率可达100.0%,30 min杀菌效果不受有机物和温度影响;1∶600稀释液在室温下作用30 min杀菌率达99.8%,30℃±2℃下作用30min可达100.0%的杀菌率.卫可1∶400稀释液在22℃±2℃和30℃士2℃下作用10 min、30 min杀菌率均为100.0%.两种消毒剂不同作用浓度在22℃±2℃和30℃±2℃下的杀菌效果均好于13℃±0.3℃.表明,卫克具有很好的杀菌效果,高浓度(1∶200)消毒时不受作用时间、有机物和环境温度的影响,低浓度(1∶400和1∶600)使用时可通过延长其作用时间和提高环境温度来加强其消毒效果.  相似文献   

6.
随着市售PET瓶装巴氏杀菌乳的脂肪挂壁不良现象的发生,本文对市售不同厂家、不同包装形式、不同杀菌温度以及不同乳脂率的巴氏杀菌乳的稳定性进行了研究调查,通过分液漏斗自然分层和多重光散射仪分别测试分析对比研究了其均质指数和不稳定性指数,结果表明,影响产品稳定性的因素有脂肪含量、保藏时间、保藏温度、产品粒径、杀菌温度.其中,...  相似文献   

7.
淀粉复配可改善单一淀粉的部分使用性质,研究前期以玉米淀粉为主料与绿豆淀粉、马铃薯淀粉和木薯淀粉按4∶2∶1∶3的比例复配,改善了玉米淀粉的透明度、冻融稳定性、抗老化性和凝沉性,但淀粉糊热稳定降低。试验以复配淀粉为原料,以磷酸二氢钠为酯化剂,尿素为催化剂,采用半干法工艺制备磷酸酯淀粉,考查影响复配淀粉磷酸酯化的因素酯化剂、催化剂用量及反应温度、时间和p H等;最佳工艺条件:反应温度140℃,反应时间30 min,p H 6.0,使用磷酸盐及尿素分别为6%和3%,改性后的淀粉含结合磷量最高可达1.7849%,优于国内市场同类产品(结合磷含量约0.2%~0.4%)。复配淀粉磷酸酯化后遇碘及甲基蓝均显色,与玉米淀粉及复配淀粉相比,其热稳定性、溶解度、透明度和冻融稳定性均有所提高。  相似文献   

8.
为了延长巴氏杀菌乳的保质期,经过长期的试验研究和生产试制,对巴氏杀菌乳的杀菌工艺进行改进,采取2次杀菌法,在均质前增加一道"杀菌"工序,并对2次杀菌工艺参数做了科学合理的筛选。结果表明:一次巴氏杀菌的最佳工艺参数是72℃、15 s,二次巴氏杀菌的最佳工艺参数是75℃、15 s。按上述工艺及参数生产出的巴氏杀菌乳在2~4℃下保质期可达6天,比通用工艺生产的产品保质期延长了3天。抽样检测产品各项理化、微生物指标均合格,降低了生产成本,大幅度拓宽了销售范围。  相似文献   

9.
[目的]研究巴氏杀菌乳贮藏温度及时间对保质期的影响。[方法]以75 ℃,15~20 s热处理的新鲜巴氏杀菌乳为研究对象,分析其在6 ℃、10 ℃、15 ℃恒温条件下贮藏,样品大肠菌群、菌落总数、酸度及感官品质的变化。[结果]巴氏杀菌乳在6 ℃条件下贮藏,产品质量可控且有保障,7 天内不会发生变质;巴氏杀菌乳在10 ℃条件下贮藏,产品质量在6 天内有保障,不易出现变质;巴氏杀菌乳在15 ℃条件下贮藏,产品质量在3~4 天内有保障,在第4~5天开始出现变质。  相似文献   

10.
为了研究银杏果实中淀粉水解的条件,分别采用液化酶和糖化酶对银杏果实中的淀粉进行酶解试验,考察不同工艺条件(如温度、时间、用量)对液化酶、糖化酶酶解银杏淀粉效果影响。结果表明:液化酶最佳酶解工艺条件:液化温度60℃、液化时间30min、液化酶添加量0.03%;糖化酶最佳酶解工艺条件:糖化温度60℃、糖化时间90min、银杏浆液糖化酶添加量0.01%,最后的酶解率可达到74%。该课题的研究为银杏饮料的研究奠定了一定的基础。  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.
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   

13.
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   

14.
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   

15.
16.
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   

17.
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   

18.
A knowledge of the microbiological status of milk and of the different structures in the mammary glands has great importance in elucidating the pathogenesis of mammary gland infections. The objective of this study was to evaluate the microbiological status of various structures in the mammary glands from naturally infected dairy cows following slaughter. A total of 94 samples of milk, 184 samples of mammary parenchyma, 168 samples of gland cisterns, and 168 samples of teat cisterns were collected for microbiological examination. Microorganisms were detected in 59.9% of all samples, 67.0% of the milk samples, 70.1% of the mammary parenchymas, 55.9% of the gland cisterns and 48.8% of the teat cistern samples. When all samples were considered, coagulase-negative Staphylococcus were the most prevalent (35.7%) followed by coagulase-positive Staphylococcus (12.2%), Corynebacterium bovis (2.4%), Prototheca sp. (1.9%), and Streptococcus dysgalactiae (1.5%). There was a significantly higher occurrence of microorganisms in the milk and mammary parenchyma compared to the gland cisterns and teat cisterns. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

19.
Four grass plots were sequentially contaminated with goat faeces containing known numbers of unembryonated eggs of predominantly Haemonchus contortus and Trichostrongylus spp. between October 1982 and April 1983. Four other plots were similarly contaminated with sheep faeces between February and May 1987. An additional plot was repeatedly contaminated with sheep faeces from February to April 1987. Populations of free-living stages in faeces and of infective larvae (L3) in the herbage were subsequently monitored until the end of April and June of 1983 and 1987 respectively. During February and May 1987 two control cultures of sheep faeces were incubated in the laboratory at 25°C–30°C and at a constant temperature of 50°C and the free-living development was also monitored. L3 developed very readily in the faeces cultured at 25°C–30°C and in those spread on a grass plot in October, at the end of the wet season, but developed less on the plot contaminated in May at the start of the wet season. Worm eggs in faeces deposited on plots during the hot dry season (December to April) or incubated at 50°C died and disintegrated after 24–48 h exposure to the high environmental temperatures. The results indicate that it is unlikely that gastrointestinal nematodes of sheep and goats can develop or survive on open pasture during the dry season in the Nigerian derived savanna zone.  相似文献   

20.
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