To check if your Nobu miso cod has gone bad, look for a few key signs. First, smell it—fresh cod should have a clean, ocean-like scent. If it smells sour or overly fishy, it’s best to discard it. Next, check the appearance. Fresh cod should look bright and moist. If it has gray or brown spots, or seems slimy or dry, it might be spoiled. Also, feel the texture; fresh cod should be firm and springy. If it’s mushy or doesn’t bounce back, it’s probably bad. Lastly, always check the expiration date. If you’re unsure, it’s safer to err on the side of caution and not take the risk. I hope this helps.