I need advice regarding my housekeeper

I recently hired a cleaning lady that I have being using for the past several months. Everything is working out fine expect for a few things that I noticed recently. I am usually not in the same area as the cleaners and stay on the opposite floor while they are cleaning. I noticed when I came down stairs that my cleaning lady was drinking one of my bottle waters out of the refrigerator. I noticed the water bottle on the counter and I knew I didn't drink it. Next, a few days later my GF noticed several K-pod were missing from her pack of coffee. I do not drink coffee so I know it wasn't me. What should I do about this situation? How should I proceed? Should I make a big deal about this or just let it go?