Keep in mind that quizzes are often a surprise, and your daughter may not have been prepared on the days she took the quizzes. While a low quiz grade is not the end of the world, it is definitely a wake-up call telling your daughter that she is not always learning what she is expected to learn. Have her study the quizzes with F grades to figure out what she failed to learn and how she should have prepared for these quizzes. This may be all that she needs to do to turn things around. Be sure to express confidence in her ability to get a handle on the more challenging work of middle school, and she is likely to do so.
Reviewing basic study and organizational skills with your daughter could be helpful. She needs to get in the habit now of listening carefully to what the teacher stresses in class as it is likely to be on quizzes as well as tests. Plus, she should review her class notes and assignments every evening if she is having a lot of surprise quizzes. If this nightly preparation does not help and she receives another low quiz grade, it's time for her to talk to the teacher about how she can do better on future quizzes.