天津大学食品微生物实验讲义.pdf

化工学院 食品微生物学 实验指导 目 录 实验一 培养基的制备······························································································- 1 - 实验二 微生物的接种与培养技术············································································- 9 - 实验三 普通光学显微镜的使用及细菌的革兰氏染色··············································- 15 - 实验四 酵母菌的形态观察、细胞大小测定及细胞计数··········································- 22 - 实验五 霉菌的形态观察·························································································- 26 - 实验六 食品中细菌总数的测定··············································································- 29 - 实验七 食品中大肠菌群的测定··············································································- 33 - 实验八 微生物菌种的分离筛选··············································································- 36 - 实验九 细菌的生理生化实验··················································································- 39 - 附录I 染色液的配制······························································································- 42 - 附录Ⅱ 培养基的配制····························································································- 42 - 附录Ⅲ 试剂和溶液的配制·····················································································- 43 - 附录Ⅳ 实验报告要求····························································································- 45 - 实验一 培养基的制备 背景知识 一、实验目的 1．了解并掌握培养基的配制、分装方法。 2．掌握各种实验室灭菌方法及技术。 二、实验原理 培养基是人工配制的，供微生物生长、繁殖、代谢的营养基质，用以培养、分离、鉴定、保存 各种微生物，或者积累代谢产物。由于微生物种类繁多，营养类型多样，对营养物质的要求各不相 同，加之实验和研究的目的不同，所以培养基的种类很多，使用的原料也各有差异。 微生物细胞化学组成包括水分、有机化合物（蛋白质、核酸、碳水化合物和类脂）、 矿物盐类及生长素，因此为了满足微生物生长和代谢需要，培养基中必须含有这些基本 的营养物质，即碳源、氮源、能源、无机盐和微量元素、生长因子以及水分等。培养基 中各营养成分的浓度与配比要合理，具有适宜的碳氮比和无机盐离子浓度等。 另外，培养基还应具有适宜的pH 值、一定的缓冲能力、一定的氧化还原电位及合 适的渗透压。不同微生物对pH 要求不一样，霉菌和酵母菌的培养基pH 一般是偏酸性 的，而细菌和放线菌的培养