How to tell if agar is still good?

First time making agar, I did a ghetto recipe and just microwaved tekked it. That was 2 weeks ago. They still look clean now, except for what seems to be a few air bubbles and unevenness. How do I know if those air bubbles and unevenness are contam growing or just imperfections? I didn’t add food coloring so its hard to tell on a translucent clear plate 😞 thanks y’all