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How To Tell If A Sweet Potato Is Bad | What Are The White Spots?

Are you trying to figure out if those sweet potatoes have gone bad? 

Are you trying to see whether that dark spot is black rot (could be, is it smell or soft too?) or if those brown spots are just the first signs that your sweet potato has gone bad? (Could just be part of the sweet potato.) Are you seeing white spots inside and you’re confused if it’s still ok to eat? (Yes, the white spots are just starchy sugar.)

If you’re unsure about this, you’re not alone. Honestly, I’ve always taken the lasting power of these starchy root vegetables for granted.

But recently, we moved and I switched up how I was storing my veggies. It turns out that may have been a mistake.

Yep, our sweet potatoes may have ultimately gone bad. No more sweetness. No more golden skin!
They say sweet potatoes last; but it turns out that they don’t last forever. 

So, let’s learn together the common traits of bad sweet potatoes. 

Yes, they do. In truth, there are many ways to tell if your sweet potatoes have finally gone bad. But more on that later.
You also have to determine whether the sweet potatoes are cooked or otherwise as the level of spoilage varies accordingly.

Here’s one thing that you have to remember when you’re dealing with sweet potatoes.

These potatoes feature a dense, creamy texture which gives them a high water content – this ultimately leads to spoilage. 

However, the more pressing question is: Just how long do they last?

How long do sweet potatoes last?

Raw sweet potatoes that are stored properly can last up to a month. 

Cooked sweet potatoes that are stored properly can last up to five days in the refrigerator.

In the freezer, cooked sweet potatoes can last up to six months.

Important note: Raw sweet potatoes don’t freeze well and I don’t recommend that as an option. 
Now, more on raw sweet potatoes! 

These whole potatoes can last for a month, if and only when you store them in a cool, dry, and dark pantry. 

So if you’re curious about what this means, your storage space should have ample air circulation and it shouldn’t be too hot or get too much sun. 

This kind of environment should extend your raw and whole sweet potatoes’ shelf life.

I learned this the hard way. I realized that where I was storing mine was getting a ton of sun late in the afternoon. 

It turns out that direct sunlight was shortening my sweet potatoes shelf life. 

This was not good for my fresh sweet potatoes.

And then, of course, there are those who rely on an unopened can of sweet potatoes.

What of them in terms of longevity? 

The ones in the can and are unopened can last up to a year.

Keep in mind that the cans generally come with a use-by date.

If you don’t notice it at first, look at the bottom of the can.

Those that are opened and exposed to air can last up to seven days when stored in the fridge.

To properly store canned sweet potatoes that have been opened, put them in shallow airtight containers and slide them right on into the refrigerator.

How to tell if a sweet potato is bad?

Uncooked sweet potatoes are very much prone to show some signs of spoilage. 

One of these is when they develop sprouts. I suggest you use up your supply as soon as you can.
There are more tell-tale signs that your sweet potatoes have gone bad.

For starters, always check for the slight or more pronounced discolorations. If you notice this move on to the feel test. 
This can be true when sweet potatoes tend to have soft spots, or are mushy when you touch them. 

The same can be said when these soft potatoes show a deep shade of brown to black hues in them.
You can also look for unusual growths in the skin of a sweet potato, along with the presence of mold. 

In the likelihood that these potatoes already come with an off-putting odor, it’s best that you toss them straight in the trash.
For mashed or cooked sweet potatoes, I recommend checking the same sign for molds. 

If you think that the potatoes feature an unappealing flavor or color, these are of no good quality and pretty much not safe to consume anymore.

What is the white inside a sweet potato?

The white ooze you’re seeing is all normal.

Experts likewise would tell us that this white substance is a sign that these sweet potatoes are extra sweet! 
We’ve all seen it: The sight of that oozing, white stuff coming out of sweet potatoes.

But are they as unappetizing as they’re something to be concerned about? 

Do you need to go back to the grocery store and get them replaced?

It’s not the worst thing, I’m telling you. Not even remotely.
Don’t believe me?

This same thing, called a normal sap, is a mixture of sugar and starch. 

It’s also not harmful and is completely safe for consumption.
Alongside sweet potatoes, you’d also see this latex-like residue in other vegetables, right when they’re cut. 

The most common of these veggies include squash and chayote.
Okay, so for the more curious: Why do some potatoes leak these saps while others don’t? Fair enough.
As per those who are adept in anything sweet potatoes, the sweeter the potato, the chances of it oozing out this sap are high.

You can blame the sugary content for this.
Organic sweet potatoes are also more likely to feature this milky residue. 

This has something to do with how they’re grown, that is in mass quantities, which ultimately reduce the accompanying, milky starch.
Another factor that you might want to consider when it comes to knowing why there’s this white sap inside sweet potatoes is the freshness that comes from them. 

The fresher these potatoes are, the more likely they are to produce this white ooze.

Other white things

If you think this is the only white thing you’ll be seeing in sweet potatoes, think again.
You may have also noticed some white spots appearing in sweet potatoes when you get to slice them in half, speckling through the inside.
Like the oozing white sap earlier, these white spots are still the starch and sugar finding their way inside through the holes they can manage to escape from.
And like the milk-like substance, these spots aren’t harmful to eat.

They can also be rinsed off easily, though be warned that the only problem is that they can be quite sticky to touch.

This stickiness wears off once the potatoes are cooked.

They could have been a yam!

Ever bought sweet potatoes but couldn’t help but ask around what in heaven’s name they are, right when you see this white flesh emanating from the inside?

Well, you might have truly purchased yourself yams instead.
Fret not, however, as yams are labeled inaccurately in some markets.

These yams are essentially a type of sweet potato, one that’s more consumed in North America.
These very yams also feature brown skin, with a white or purple flesh.

Sweet potatoes, on their end, have orange flesh.
In terms of taste and texture, yams and sweet potatoes share these qualities quite almost the same.

Although some would attest that yams are slightly less sweet and often come with a drier texture.

Black spots on sweet potatoes?

Seen those black spots in your sweet potatoes after peeling them?
Dubbed as the internal black spots, these spots are “bruising” that occurs when potatoes tend to lie against each other for an extended period.

Worrisome as they may seem, sweet potatoes with these spots are still safe to eat. Simply get rid of the sport.
Note, though, that when sweet potatoes already come with a considerable amount of Fusarium, that filamentous fungus that’s widely distributed in plants and soils, you may start noticing an unappealing flavor.
While we’re at the “unappealing,” how about those sweet potatoes that come with mold? Is it a sign of spoilage?
Accordingly, it is not. Sweet potatoes with molds on the outside are still edible.

If you also happen to spot sprouts growing from these potatoes, it’s best that you just cut them off and cook them ASAP.
Finally, when you see mold spots in your sweet potatoes, this is when you start throwing them away.

What are these holes in my sweet potatoes?

The holes in sweet potatoes are caused by wireworms.

Found in the root crops, these worms can be witnessed during the harvest season and may affect potatoes, to the point that they go to waste.

But are sweet potatoes with holes safe to eat? To rip the band-aid off for you, yes, and it’s the case most of the time.

Not all sweet potatoes with spots are bad, so to speak.

So, the next time you get to see some spots in your prized sweet potato fries, don’t panic.
You only need to cut these holes with care and they are already good for consumption.

Tips on storing sweet potatoes

Craving for fresh and tasty sweet potatoes?

These quick storage conditions and procedures should get you started.
After you wash sweet potatoes and dry them with a paper towel, it’s suggested that you do the following:

  1. Avoid storing sweet potatoes in the fridge. This often produces a hard center, plus that truly unpleasant taste.
  2. You can store sweet potatoes in cool, dry, and well-ventilated containers instead.
  3. For best results, keep them in a basement or a root cellar, as they will keep your sweet potatoes away from strong heat sources.
  4. Though it isn’t recommended to bank the tubers in sand as it doesn’t allow for adequate ventilation, you can still store them accordingly, provided that the sand is packed in layers in barrels or crates.

Can you freeze sweet potatoes?

Yes. Freezing sweet potatoes should let them thrive for up to a year.

You just need to know how to do it correctly.
For instance, when you freeze boiled sweet potatoes, you have to learn how to prepare them before freezing.

The same is true when freezing baked and mashed sweet potatoes.

The bottom line

While sweet potatoes pale in comparison when seated side-by-side with potatoes when it comes to versatility and popularity, the former is still as fun and exciting to prepare and consume from time to time. Crispy sweet potato skins, anyone?
This is especially true when you consider the many ways you can extend the life of a sweet potato.

And one of the surefire ways to maximize your time on doing this is to determine first, by and large, whether these sweet potatoes have already gone bad.