Petra is working on a project that is looking for ways to improve milk yield. What is Petra's job title

Petra's job title is a researcher

Explanation:

Who is a researcher?

A researcher is someone who takes on a particular project, that involves systematic and organized investigation either to improve on something, make a new finding, or a novel invention or results.

Back to our question Petra can also be called a scientist, analyst, investigator, experimenter, analyzer, tester, and she can work in the research and development (R&D) of a food related industry