How would you handle this.

I had orientation for a new job and when I went to the department I'd be working in, they have their own break room with sink, microwave and fridge. It was nasty snd dirty back there. When I opened the fridge, it was full of stuff and smelled like rotten food. When I said something about it, the supervisor said oh it's probably just the fries in that take out box. But it didn't smell like fresh food to me. Now I have to bring my own cleaning supplies and take it upon myself on one of the first days I work and clean, clean, clean. I told the woman in HR about it, she said oh I believe it because when I worked that department, I had to clean up all the time. She said she would send them an email about it. But even if people kinda cleaned it out, it will still be nasty