The Danger Zone: Shredded Cheese Left Out

How long is it safe to leave shredded cheese out? This is a question with no definitive answer, as it depends on a variety of factors. The type of cheese, moisture content, temperature of the room, and whether it is fresh or aged all play a role in determining how long shredded cheese can safely be left unrefrigerated. The U.S. Department of Health recommends that perishable foods, including soft cheeses, should not be left out of the fridge for more than two hours. Harder cheeses, such as cheddar, can be left out for up to four hours, according to the Dairy Farmers of Wisconsin. However, it's important to inspect any cheese that has been left out for signs of spoilage, such as an unpleasant smell, a slimy surface, dark spots, dryness, cracks, or mold.

Leaving shredded cheese out overnight

Shredded cheese has a larger surface area relative to volume compared to a block of cheese, which makes it more susceptible to spoilage. Additionally, the temperature of your house can impact how long cheese can be left out, with higher temperatures increasing the risk of spoilage.

If you do find yourself with shredded cheese that has been left out overnight, there are some steps you can take to assess its safety. Firstly, check for any signs of spoilage, such as a bad smell, slimy surface, dark spots, dryness, cracks, or mould. If the cheese exhibits any of these signs, it should be discarded. If there are no visible signs of spoilage, you can try smelling it or doing a small taste test. If it seems okay, you may still be able to consume it, but it's important to exercise caution as there may be microscopic bacteria present.

To prevent shredded cheese from spoiling in the future, it's important to store it properly. Avoid tightly wrapping it in plastic wrap or a plastic bag, as this can reduce its quality and flavour. Instead, try using parchment paper, cheesecloth, butcher paper, cheese storage bags, or beeswrap. Store the cheese in the vegetable drawer of your refrigerator, where the temperature is cold and stable with consistent humidity.

How to tell if cheese has gone bad

Leaving shredded cheese out overnight is generally not recommended, as it can compromise its quality and taste. However, if the bag was unopened and sealed, it should be safe to consume. It is always a good idea to check for any signs of spoilage before consuming cheese that has been left out.

Appearance

Cheese that has gone bad may exhibit changes in appearance, such as a slimy or greasy texture, discolouration, or surface mould. If the cheese is covered in thick mould, it is best to discard it. However, if there is only a small amount of mould on a hard cheese, you can cut off the affected area with a clean knife and consume the rest of the cheese as long as it looks and smells okay.

Smell

Spoiled cheese can have an unpleasant or "off" smell, which can vary depending on the type of cheese and the stage of spoilage. It may smell rancid, sour, putrid, or like ammonia, urine, or cleaning products.

Taste

If the cheese has an unpleasant aftertaste, such as bitter, acidic, or unpleasantly sour, it has likely gone bad.

Texture

Changes in the texture of the cheese, such as hardening or cracking in hard cheeses, or sliminess in soft cheeses, can indicate spoilage. If the cheese has become gritty or grainy, especially in soft washed rind cheeses, it is likely spoiled.

The impact of temperature on cheese

Temperature has a significant impact on cheese, influencing its flavour, texture, and safety.

Ripening and Flavour Development

Cheese stored at warmer temperatures will ripen faster than cheese stored in cooler conditions. For example, a whole wheel of Camembert, which usually takes weeks to ripen in the fridge, can be ripened in a day or two at room temperature. This is because the enzymes in the cheese stay active at warmer temperatures, leading to the development of a gooey texture and more complex flavours.

Texture

The temperature at which cheese is stored can also affect its texture. For instance, high temperatures can cause the fat in the cheese to "melt", resulting in oozing and the formation of droplets on the rind, which can give the cheese a rancid taste. On the other hand, lower moisture levels achieved through lower temperatures can make the cheese firmer and drier.

Food Safety

Temperature control is crucial in preventing the growth of pathogens in cheese. Higher temperatures can activate bacteria in the cheese, which process lactose and produce carbon dioxide, leading to the cheese inflating. Additionally, some types of semi-hard cheeses can develop "mucor" around the rind at warm temperatures and high humidity. This mould is highly spreadable and can easily contaminate other cheeses.

The best way to store shredded cheese

Shredded cheese is a convenient way to add flavour and texture to a variety of dishes. However, it can quickly go bad if not stored properly. Here are some tips to ensure your shredded cheese stays fresh and tasty:

Choose the Right Cheese

Start with a block of good-quality cheese. Harder cheeses, such as cheddar or Swiss, are ideal as they have a longer shelf life than softer varieties. Harder cheeses also have a lower moisture content, making them less susceptible to bacterial growth.

Shred Your Own Cheese

Shredding your own cheese is not only cost-effective but also ensures you avoid any additives found in pre-shredded cheese, such as cellulose, an anti-caking agent. By shredding your own cheese, you can also control the thickness of the shreds, which can enhance the melting and overall texture of your dish.

Store in Airtight Containers

Once you've shredded your cheese, store it in an airtight container, such as a plastic zipper bag or a hard-sided box. You can also use the original bag if it's resealable. Make sure to remove as much air as possible from the container before sealing.

Freeze for Long-Term Storage

Shredded cheese can be frozen for up to three months. It's best to use it directly from the freezer, as the texture may change slightly upon thawing. Frozen shredded cheese is perfect for cooking, as it will melt evenly and any changes in texture will go unnoticed.

Keep an Eye on Freshness

Even when stored properly, shredded cheese has a limited shelf life. Pre-shredded cheese typically lasts about five days in the refrigerator, while shredded cheese from a block can last a few days to a week. Always check for signs of spoilage before using, such as an unpleasant smell, a slimy surface, or the presence of mould.

The difference between hard and soft cheeses

The safe window for leaving shredded cheese out of the fridge is around 2-4 hours. After this time, it's recommended to check for signs of spoilage. If the cheese has been sitting out for longer than two hours, it may change in quality and taste.

Now, onto the difference between hard and soft cheeses.

The main difference between hard and soft cheeses is their moisture content. Soft cheeses are made by allowing the curds to drain slowly, retaining a lot of moisture. The greater the moisture content, the softer the cheese. Hard cheeses, on the other hand, are cut into smaller pieces to release more whey, and then subjected to higher temperatures to remove even more moisture. They are then placed under tons of pressure to force out as much water as possible.

Hard cheeses, such as Parmesan and Gruyere, are aged for longer periods, resulting in a distinct crumbly texture. These cheeses are made by removing most of the whey from the curds, which removes a lot of the moisture. They are then either brined or waxed and aged for an extended period, which further dries out the cheese.

Semi-hard cheeses, like cheddar and Swiss cheese, are aged similarly to hard cheeses but for a shorter duration. They have a firm yet slightly springy texture and a dense consistency.

Semi-soft cheeses have a higher moisture content, resulting in a smoother, creamier texture. Examples include Havarti, Muenster, and Butterkäse.

Soft cheeses, also called fresh cheeses, have the highest moisture content. They are made from fresh curds that have not been pressed or aged. Examples include cottage cheese, cream cheese, mozzarella, and burrata.

Frequently asked questions