Does String Cheese Go Bad? How Long Does It Last?

Here’s everything you need to know about the shelf life, storage, and spoilage of string cheese. Learn how long it lasts, when to toss it, how to store it, and more.

Not sure if string cheese that sat the whole day in your child’s rucksack is still okay to use? Does string cheese go bad if not refrigerated?

Or maybe you opened a package of string cheese a few days ago, and you’re wondering for how long will the cheese stay fresh and tasty. Or if you can freeze the leftovers instead of desperately trying to fit them into your meals.

Sounds familiar?

If so, this article is for you. Read on.


In this article, I talk about American string cheese. It’s sold in the form of sticks of low-moisture mozzarella, as you can see in my photos. Sometimes these are also called mozzarella sticks or cheese sticks.

String cheese package
String cheese package

How Long Does String Cheese Last?

String cheese comes with a date on the label. In most cases, it’s a sell-by or use-by date, but it’s not uncommon for it to have a best-by date.

No matter which variety it is, you should know that generally, string cheese has a pretty long shelf life of at least 6 to 8 weeks. And it usually stays good for an extra 2 to 3 weeks.

Once you open the package and it’s not of those with single-wrapped sticks, try to finish the cheese within around 7 days for the best quality.

Of course, if you keep good care of the food product, it will last longer. There’s no way of saying how long will it last exactly. That depends on the storage conditions, the quality of the cheese, and its ingredients.


If your sticks are single-wrapped, assume each one has the shelf life of an unopened package.

String cheese (unopened)Date on the label + 2 – 3 weeks
String cheese (opened)1 week
Please note that the periods above are estimates and for best quality.
String cheese: date on the label
String cheese: date on the label

How to Tell if String Cheese has Gone Bad?

First off, look for the usual signs of spoilage, such as odd aroma, any organic growth or bluish-grey specks on the surface of the cheese. If any of these are present, throw the string cheese out.

If you already store the sticks for much longer than you should, i.e., opened for like 3 weeks or unopened for 2 months past the date on the label, err on the side of caution and get rid of the package.

Assuming that everything about the cheese seems to be okay, give it a taste, and based on that decide if it’s good enough in terms of quality.

If it’s not, cut your losses and throw it out. And definitely don’t try to add it to your kid’s lunch. If you want to sneak in some dairy into your child’s diet, using old cheese is not the way to go.

Wrapping cheese stick in a freezer bag
Wrapping cheese stick in a freezer bag

How to Store String Cheese

Like almost all dairy products, you should store string cheese in the fridge.

Once you open the package, make sure you seal it tightly before putting it back into storage. If that’s not possible, transfer the package into a freezer bag and squeeze as much air out before you seal it.

Quite often each cheese stick is separately wrapped (see my photo below). If that’s the case for yours, no need to seal the package tightly.

Wrapping is important for two reasons:

  • Cheese likes to pick up odors, and you definitely don’t want string cheese that smells like sausage.
  • A good seal prevents air pockets from forming around the cheese and drying it out.

If you’re adding a cheese stick cheese as a snack to your child’s lunch box, putting it in a separate container or freezer bag for additional protection would be ideal. Or going with the single-wrapped mozzarella sticks.

If the cheese has to sit with other food items, make sure there’s nothing moist like cut tomatoes in there because the cheese will taste pretty bad after an hour or two.


Interested in freezing mozzarella sticks? Here’s my take on the question: can you freeze string cheese?

Single wrapped mozzarella sticks
Single wrapped mozzarella sticks

How Long Can String Cheese Sit Out?

There isn’t a good answer to this question.

On one hand, you should refrigerate string cheese at all times, and not let it sit out for longer than 2 hours, for safety reasons.

On the other hand, if you add a cheese stick into a lunch box, it’s going to sit in a relatively warm temperature for much longer than those two hours.

My advice: use common sense.

If that string cheese isn’t spoiled or super old, and it’s well wrapped, it’ll most likely be perfectly fine after those 4 to 5 hours in the lunch box. Maybe its quality won’t be top-notch anymore, but that’s about it.

Semi-soft cheeses, like mozzarella sticks, degrade quite quickly at room temperature. Therefore, changes in taste are quite possible if it’s left out for too long.

When it comes to your child returning home with that cheese stick, it’s up to you what you’re going to do with it.

While the quality probably won’t be top-notch anymore, it should be good enough to eat. Unless it’s the middle of a hot summer, of course.

It’s really up to you to decide. But I definitely wouldn’t put that mozzarella stick back to the fridge to add it to lunch the next day. Either use it now or discard it.

Want to learn more about cheese in general?

Check out our guide:

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