共查询到19条相似文献,搜索用时 171 毫秒
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原料奶中嗜冷菌的测定 总被引:6,自引:4,他引:2
1概述如果UHT奶制品中发现有耐热蛋白酶存在(产品有凝块或发苦),或者有脂肪酶存在(产品有脂肪氧化味)时,则应对原奶中的嗜冷菌进行检验。2材料及仪器内装99ml无菌稀释液的烧瓶;氯化钠水溶液(浓度0.7%,用于制备稀释液);蒸馏水;无菌培养皿(预先灭... 相似文献
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根据专家预测和国家有关统计,目前全国共拥有600万头奶牛,2003年乳品工业总产值达350亿元,奶业产业链的市值达1000亿元左右。同时,过去9年的牛奶消费量共增加了66%,而2001年1年的奶制品市场需求额竟比2000年增长37.9%,可见市场的迅速发展是前所未有的。尽管如此我国目前 相似文献
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在UHT奶产业链调研分析总结的基础上,利用网络数据库技术设计建立了网络化的UHT奶安全可追溯系统。该系统采用浏览器与Web服务器技术(B/S结构),客户端是浏览器,不需要其他客户端设备。利用DrearnweaverMX2004开发系统网络界面,通过ASP和SQLServer网络数据库技术把安全追溯系统放在互联网上.奶牛场和加工企业通过网络上传收集的追溯信息.储存到企业服务器数据库。加工厂可以通过浏览器快速再现单个产品详细的生产信息.快速确定此产品原料乳的来源和同批次产品去向。即时发现UHT奶产业链中存在的问题,更好的保证产品的质量安全:奶牛场可以快速查询原料乳的生产和验收信息,及时掌握奶牛的产奶情况;消费者可以方便快速的查询所买单个产品的相关信息。增强了UHT奶产业链的透明度,保障消费者的合法权益。 相似文献
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The objective of the article was to analyze the influence of psychrotrophic bacteria counts (PBCs) and somatic cell counts (SCCs) on the extent of lipolysis in bulk samples of cow's milk at reception and during cold storage. Samples of milk were analyzed on the day of sampling and subsequently during cold storage. The acidity, fat, density, chloride content, electrical conductivity (EC), bulk milk SCCs (BMSCC), and PBC values were analyzed on the day of sampling and the levels of acidity, EC, SCC, and PBC were analyzed during cold storage at 4 °C for 72 h. The SCC value 869 × 103 mL?1 was higher than the recommended threshold. Lipolysis level at sampling day was related more closely with SCC than with PBC. There was no significant correlation between milk acidity and PBC among others parameters, while the milk mean density was only significant (P < 0.01) correlated with the fat content. The EC and chloride content were consistently correlated (P < 0.001) with BMSCC that allowed them to be used as indicators of mammary gland infection. The milk acidity, EC, PBC, and lipolysis levels increased in relation to the storage time at 4 °C. The lipolysis level during storage was in closer relation to the SCC, but not relation to the PBC. Effects of SCC and PBC on lipolysis decreased throughout the chilling period. It was concluded that initial lipolysis level and intrinsic milk lipoprotein lipase appear more effective than SCC and PBC on the development of lipolysis during storage. 相似文献
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本文对影响UHT塑袋牛奶质量的原料乳、包装膜、检验、设备和操作等进行了阐述,归纳了UHT奶常见质量问题及解决措施,提供了企业控制UHT奶质量的相关经验,可供乳品企业参考. 相似文献
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良好生产规范,是国际上普遍采用的食品生产先进管理方法,它是在食品生产全过程中保证食品具有高度完全性的良好生产管理系统。文章列举了超高温奶生产的GMP中的主要内容。 相似文献
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超高温灭菌乳在贮藏过程中的质量变化 总被引:5,自引:2,他引:5
对经超高温灭菌乳在贮存过程中发生的一些感官、理化、微生物的变化进行了观测,并根据结果来探讨延长超高温灭菌牛乳保质的方法。分析了引起这些变化的原因并提出了一些控制措施。 相似文献
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Marilù Decimo Stefano Morandi Tiziana Silvetti Milena Brasca 《Journal of food science》2014,79(10):M2081-M2090
Eighty psychrotrophic bacterial strains, isolated from different northwest Italian bulk tank milks destined for Grana Padano cheese production, were identified by 16S rRNA gene amplification and partial sequence analysis of the rpoB gene. Pseudomonas spp. were the most commonly occurring contaminants, P. fluorescens being the predominant isolated species, along with Enterobacteriaceae, primarily Serratia marcescens. RAPD‐PCR was used to study genetic variability and distinguish closely related strains; a high degree of genetic heterogeneity among the strains was highlighted. All the strains were characterized for their ability to produce proteases, lipases and lecithinases at different temperatures (7, 22, and 30 °C). Forty‐one of the psychrotrophic strains were positive for all the enzymatic activities. The highest number of positive strains for all the incubation temperatures was found for lipolytic activity (59), followed by proteolytic (31) and lecithinase (28) activities, and the enzymatic traits varied among the Pseudomonas and Enterobacteriaceae strains. The proteolytic psychrotrophic strains were screened for the presence of the aprX gene, coding for a heat‐resistant metalloprotease in Pseudomonas spp. The aprX gene was detected in 19 of 63 Pseudomonas strains, and was widespread in the P. fluorescens strains (14/19). 相似文献