To broaden and emphasize the educational benefits of research to more biology majors in a course setting, we developed and assessed a microbiology-focused course-based undergraduate research experience that utilizes culture-based bacterial enumeration to compare contamination present on different ground beef sources (conventional vs. organic). During the final 3 weeks of the quarter, students learned and practiced common microbiology techniques like dilution math, selective and differential media-based identification, and statistical analysis to evaluate data and test hypotheses. Students were assessed primarily via a formal lab report and a lab practical focused on evaluating process of science and quantitative reasoning skills. The majority of students could write hypotheses and describe variables but were challenged when asked to describe the limitations of the experiments that were conducted as part of this research project. Most students could perform Excel-based graphing and a t test, but many could not solve the complex dilution math required for this project. The greatest barriers to skills mastery represented microbiology-focused concepts, like understanding selective media biases and the nuances of multistep viable counting procedures and outcomes.

中文翻译：

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肉类的治疗方法：比较不同地面牛肉来源上的细菌污染物强调了科学和定量推理的过程。

为了在课程设置中扩大和强调研究对更多生物学专业的教育益处，我们开发并评估了以微生物学为重点的基于课程的本科生研究经验，该经验利用基于文化的细菌计数法比较了不同碎牛肉来源上存在的污染（常规相对于有机）。在该季度的最后3周内，学生学习并练习了常见的微生物学技术，例如稀释数学，基于选择性和差异介质的识别以及用于评估数据和检验假设的统计分析。主要通过正式的实验室报告和侧重于评估科学过程和定量推理技能的实验室实践对学生进行评估。大多数学生可以写假设并描述变量，但是当被要求描述作为该研究项目一部分进行的实验的局限性时，他们受到了挑战。大多数学生可以执行基于Excel的绘图和测试，但是许多学生无法解决该项目所需的复杂稀释数学。掌握技能的最大障碍代表着以微生物学为中心的概念，例如理解选择性培养基偏倚以及多步可行计数程序和结果的细微差别。