Carbide returns with mangoes

Mangoes ripened with calcium carbide could cause serious health problems, experts warn as the mango season kicks in.

Videos about how to identify carbide-treated mangoes are doing the rounds, but horticulturists say much of the information they are peddling is unfounded.

Some influencers claim that if a mango is dropped in water and it stays afloat, it is proof that it is ripened with calcium carbide. 

Not so. An authentic way to check for calcium carbide dusted or sprayed on the mango is to look for traces of the chemical, says B G Hanumantharaya, senior scientist and head of Krishi Vigyan Kendra in Doddaballapur.

“While most people in the cities clean fruits before consuming them, not all do it. And even after cleaning, dusted calcium carbide can stay on the fruit and get into one’s body,” says Hanumantharaya. 

With the carbide-treatment method, acetylene is released, which causes the fruit to “look ripe” even when it is not physiologically mature. “The fruit softens, changes colour and develops some sweetness, but that is not the actual taste of the fruit,” he explains. 

When shopping for mangoes outside, pick them up and smell them. “If you get a stinging aroma, it is treated with calcium carbide. However, continuous exposure to the mangoes masks the smell. If you want to test another mango, take a break and try again,” Hanumantharaya says.

When picking up mangoes, physically check if they have a powdery or dusty coating on them. “When you bring it close to your nose, if you get a pungent smell (‘ghaatu’ in Kannada), it is carbide-treated. In such mangoes, even if they are wiped, they will still not emit a natural mango smell,” he adds. 

However, some mango varieties can naturally have a powdery surface. “This is the bloom of the fruit and looks just like ash (like in ash gourds). This surface, even when wiped, will not come off,” he explains.  

B Sridhar, retired horticulturist, IISc, says artificially ripened mangoes are warmer when touched. “This proves that the process of conversion of starch to sugar is ongoing. Organically ripened mangoes are comparatively cooler,” he adds. 

Carbide-treated mangoes, when brought close to the face, feel itchy, says Sridhar. “Also, when one is around shops selling such mangoes, you sense a gas-like smell,” he says. Most mangoes like Raspuri and Alphonso have a distinct smell but it is blinded by this chemical smell. Sridhar says the area around the neck (at the stalk), should not be hollow. “If it is filled, then the mango is well-matured,” he says. 

When calcium carbide is dusted on mangoes for ripening, there could be black-brown spots on the fruit’s skin. 

Shop from trusted sources

Ripening of fruits using calcium carbide is banned in India. C G Nagaraju, managing director of the Karnataka State Mango Development and Marketing Corporation, says sourcing mangoes directly from farmers in areas around Bengaluru, like Kolar, Chikkaballapur and Ramanagara, is safer, as “farmers there have been trained to harvest properly”. 

To buy mangoes online, the corporation’s website is a good place: karsirimangoes.karnataka.gov.in 

‘Ethylene treatment safe’

Hanumantharaya says mature mangoes treated with ethylene ripeners are safe. “The base (caustic soda) and acid (ethylene liquid) used to produce those ethylene fumes are safe. This autocatalytic production of ethylene gives a signal to the mature fruit to synthesise inside, which leads to the fruit changing colour, developing flavour, breaking down carbohydrates to sugar. Despite chemicals being used here, the fruits are safe,” he explains.

Despite alternative methods being available, some mango sellers and farmers still prefer the calcium carbide method “due to improper understanding and the ethylene method being a little more time-consuming”, says the scientist.

Effects of calcium carbide

Carbide-treated mangoes can be carcinogenic. Also, they can burn the skin, leave eyes hurting and lead to ulcers developing in the mouth, experts say.