You can’t tell how a banana was ripened by looking at it

A post on Instagram claims that bananas with black spots and green stalks have been “chemically ripened” while bananas with black stalks have been “naturally ripened”.

This isn’t true. You can’t check how a banana has been ripened just by looking at it. And even if you could, you can’t buy a “naturally ripened” banana from a UK supermarket. 

How fruit ripens 

When bananas ripen, their starches break down into sugars, making them sweet and better to eat (arguably).  

Many fruits ripen through exposure to a gas called ethene, also known as ethylene. This is a naturally occuring gas that plants produce themselves. 

Bananas naturally emit ethylene and that’s why you might have noticed that your other fruit tends to ripen quicker when they’re in the presence of bananas.

But, nowadays, the ripening process is controlled and sped up by placing bananas in ripening rooms which are then pumped with ethylene.

Unripe bananas are shipped from where they are grown to their target market, where they are then ripened for sale.

This seems to be what is referred to in the post as “chemically ripened” bananas, though of course “naturally ripened” bananas are ripened by exactly the same chemical, it’s just that they produce that chemical themselves.

Regardless, there just isn’t a consistent difference between what these two types of banana look like.

Differences between bananas

As Reuters wrote earlier this year, a 2019 article in the International Journal of Food Science says “most studies suggest that there is no difference in biochemical composition and sensory quality in bananas treated with chemicals that induce ripening from naturally ripened bananas.”

In 2019, Snopes talked to Maricruz Ramirez Sanchez, an expert in post-harvest technology at the University of Costa Rica’s Agronomy Research Center, who said it would be possible to see green stems in both naturally ripened and ethylene-treated bananas, adding that “there is no visual test, and there is no chemical test, to confidently assess if a banana has been ethylene treated or naturally ripened.”

The Instagram post shows what it claims are “naturally ripened” and “chemically ripened” bananas, but both appear to be from the same batch, going by the sticker on each, which suggests they were ripened in the same way. 

The black stems shown in the supposedly “naturally ripened” banana could be an indication of a fungal infection called crown rot. The black spots on the “chemically ripened” banana appear to be senescent spots, a sign of ageing or that bananas might be over-mature.

Even if there was a difference, you can’t just buy a “naturally” ripened banana in the UK. 

Banana Link, a UK-based not-for-profit working to improve standards in banana production, told Full Fact that all bananas sold in the UK are ripened in ripening rooms first. It’s the same case in the United States which is where the Instagram account that published the post says it is based.