If you eat a little moldy mozzarella, it usually causes no serious problem, but it can upset your stomach and, in some cases, cause food poisoning symptoms like nausea, vomiting, or diarrhea. Soft cheeses like mozzarella should generally be thrown away if mold is present, because mold can spread through the cheese and harmful bacteria can grow with it.

What to watch for

  • Mild reaction: stomach discomfort, nausea, or an off taste.
  • More serious reaction: vomiting, diarrhea, fever, or symptoms that persist.
  • Higher risk: people with weakened immune systems, older adults, pregnant people, and young children.

What to do

  1. Stop eating the cheese.
  2. Rinse your mouth and drink water.
  3. Watch for symptoms over the next several hours.
  4. Seek medical help if you develop severe symptoms, trouble breathing, or signs of dehydration.

Mozzarella vs. safer moldy cheeses

Mold is sometimes safe in specially made cheeses like blue cheese or Camembert, but that is very different from random mold growing on mozzarella in your fridge. Soft cheeses are especially risky because mold and bacteria can spread beyond what you can see.

If you want, I can also give you a quick “throw it out or keep it?” guide for mozzarella.