A research problem is an area of concern or a gap in the existing knowledge that points to the need for further understanding and investigation. A problem statement is used in research work as a claim that outlines the problem addressed by a study. The problem statement briefly explains the problem that the research will address. If the topic of your research is food safety in the school feeding system, you need to first identify why food safety is lacking in schools. Your problem statement can explain that food safety in school feeding systems is an inmportant concern and point towards a gap in research that shows that this problem has not been addressed.

Here is a step-by-step guide that will tell you how exactly you can write a great problem statemnt for your paper: The basics of writing a statement of the problem for your research proposal

You might find this in-depth course helpful: How to write a statement of the problem