Why Is My Raw Potato Black Inside and 3 Ways to Prevent It

Cutting into your potato and finding dark-colored areas inside of it can be a cause for alarm. People get food poisoning all the time, and it’s much better to be safe than sorry when it comes to your health. 

These black areas in the potato can cause you to question if you should throw away the vegetable or continue to cook with it. 

You might be asking these questions: What are the reasons potatoes turn black inside? Does it mean your potato is done for and no longer safe to cook or eat? 

Cause of Potatoes Turning Black Inside

A picture of potatoes on a cloth placemat.

There are several reasons potatoes turn black inside. Depending on the cause, your potato may or may not be safe to eat. Bacterial and fungal infections are possible with any vegetable, including starchy tubers. 

If your potato was not infected during planting though, there are other more likely reasons that your potatoes may turn black inside. 

Bacterial and Fungal Infections 

Like with all vegetables, bacterial or fungal infections can find its way into your produce. These can spoil your food and make you sick. 

Supermarkets usually have reasonable quality control. However, an infected crop can still find itself in a store, and consumers might run into them from time to time. 

Bacteria, pests, or fungal infections can occur when the potato is still in the ground. These affect the leaves, roots, and soil of the potato. They may cause several potatoes to rot and become inedible. These are a particular concern for commercial farmers. 

However possible, it’s unlikely that the blackness on your potato is due to one of these causes.

It’s more likely the blackness of your potato is because you stored the potato at too cold of a temperature.

Probable Cause: Cold Storage 

When you store a potato at a low temperature, the insides have sugar that turns black. These are likely the black spots you see inside your potato.

The sugars will make those particular parts of the potato sweeter than the other parts. If you plan to fry the potato, however, the black spots will look unappealing to any unsuspecting guests of the dish. 

The black spots are called frost damage. Frost or cold damage occurs when the potato stays too cold for too long. Symptoms may occur while the potato is in the ground or if you keep your potato in your fridge at too cold a temperature. 

Related: How to Grow Magic Molly Potatoes

Are Black Potatoes Safe to Eat?

In the case of frost damage, the potato is still safe to eat. If you find the black patterned area unappealing, you can cut around it and use the lighter colored areas for your dish.

When in doubt, throw it out.

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What to Look For

Dark patterns on the inside or outside of the potato can be dangerous. It’s essential to incorporate your other senses if you’re unsure if the potato is safe or not after you see what could be an infection or rotting.

If your potato has a foul smell, mushy texture, or areas that look unquestionably infected, it’s best just to discard it. Use your other senses to tell you if your vegetable is spoiled or not.

How to Store Potatoes: Curing and Storage

Storing your potatoes properly will extend their life and ensure that they are safe to eat. Keeping your potatoes in optimal conditions is one of the best ways to prevent potatoes from turning black inside. 

Begin the process of storage by thoroughly washing your potatoes. Remove all visible soil and look out for any damage to the skin. After cleaning the potatoes, take the time to dry your potatoes before you store them.

Use potatoes with visible damage as soon as possible, as these are at the highest risk for infection or further damage. Do not store these potatoes for extended periods. 

Now that your potatoes are cleaned and dried, it’s time to store them. There are three factors you have to consider when keeping your potatoes the right way. These factors are temperature, humidity, and time. 

It may be challenging to find a perfect spot in your kitchen to meet the optimal temperature and humidity, but you should work with the best area you have to get the best results. 


Do not refrigerate your potatoes. Remember, dark areas of frost damage appear when you store the potatoes in a cold place.

The optimal temperature for potato storage is between 40 degrees Fahrenheit and 65 degrees Fahrenheit. Make sure you designate a proper area in your home to keep your potatoes at this adequate temperature. 

You should also make sure that the temperature doesn’t go too high. If bacteria are growing on your potatoes, the colony will spread faster if the temperature is high enough. Low temperatures inhibit the spread of bacteria. 

You can keep your potatoes in a box or a basket and then cover them so no light will get in. Light will cause your potatoes to turn green, and they will also begin to sprout. 


Potatoes need a well-ventilated area with high humidity. Ideally, you should store them in a place of 95% humidity. However, you can just find the space in your house with the highest humidity to keep your potatoes.

High humidity slows potato shrinkage. The moisture from the humid air will keep your potatoes from losing weight. 


The potato curing period will toughen up the skins of your potato. 

If you follow the process of keeping your potatoes in the optimal conditions of temperature, humidity, and reduce light exposure, your tubers will last a reasonable amount of time.

Potatoes will stay edible under these conditions for several months. 

Final Thoughts 

Your potatoes have likely turned black on the inside because you stored them in your refrigerator or another area where the temperature was too cold. 

If you follow our instructions, you will find that you can keep your potatoes for quite some time. Keep in mind the proper temperature and humidity to keep your tubers fresh for cooking.