By Dr Brij Mohan Sharma
The Food Safety and Standards Authority of India (FSSAI) has issued a critical safety alert addressing the widespread use of calcium carbide for artificial fruit ripening by fruit sellers. This industrial-grade chemical, often referred to as ‘masala’, poses significant health risks due to its toxic impurities such as arsenic and phosphorus. Despite being banned under the Food Safety and Standards Act, 2006, the use of calcium carbide remains prevalent due to its low cost and easy availability. FSSAI’s alert underscores the urgent need to enforce regulations and promote safer, approved methods for fruit ripening to safeguard public health.
During the natural ripening process, fruits undergo several chemical changes that transform their taste, colour, and texture. The breakdown of starch into sugars gives the fruit a sweeter taste. The skin colour of the fruit typically changes from green to red, yellow, or other hues due to the degradation of chlorophyll, allowing other pigments to become more visible.
Starch, the main polysaccharide stored in fruits, undergoes enzymatic breakdown and hydrolysis during ripening. This process converts water-insoluble starch into smaller, water-soluble saccharides like sucrose, glucose, and fructose, which contribute to the fruit’s sweeter flavour. Although ripened fruit still contains a significant amount of acid, its sour taste is masked by the large quantities of sugar present.
The cell walls of fruits are composed primarily of polysaccharides, mainly pectin. During ripening, various enzymes, including polygalacturonase, convert this insoluble pectin into a soluble form, resulting in a softer texture as the cell walls become less firm. Raw fruits also contain high amounts of organic acids such as malic acid, citric acid, ascorbic acid, and tartaric acid, giving them a sour taste. As the fruit ripens, these acids are broken down, such as in guavas, which show a decrease in Vitamin C content compared to their raw state.
Humans have adopted various methods to ripen fruits, such as cutting the fruit, placing it in closed chambers, and providing high-temperature conditions. A significant discovery was made by Russian scientist Dmitry Nelyubow in 1901, who found that ethylene gas affected ripening. This was later confirmed by other scientists, who found that plants produce ethylene naturally. When fruits are injured or exposed to high temperatures, they ripen faster because the diffusion rate of ethylene gas increases in the affected areas.
Fruits are classified into two categories: climacteric fruits, which continue to ripen after being harvested (e.g., mangoes, bananas, guavas), and non-climacteric fruits, which do not ripen after being harvested.
Ethylene is the main natural ripening agent, but artificial ripening agents are used to produce ethylene and accelerate the ripening process. Traditional methods involve placing fruits in wooden boxes lined with hay and lighting a wood fire underneath to produce ethylene-rich smoke. In some cases, generators produce ethylene gas, regulated by sensors. Fruits are also ripened by placing them in plastic bags or large rooms where ethylene or acetylene gas is introduced. For example, bananas are picked when hard and green, transported in this stage, and exposed to ethylene gas to ripen upon reaching their destination.
Calcium carbide (CaC2) is the most common and widely used artificial ripening agent in South Asia, including India. Known as ‘masala,’ it is produced industrially for acetylene production. The commonly available market grade contains 80-85% calcium carbide and produces a garlic smell in the presence of moisture. When sprayed with water, it reacts chemically to produce acetylene (C2H2), which acts like ethylene to ripen fruits. However, industrial-grade calcium carbide contains impurities like arsenic and phosphorus, posing significant health risks.
While these agents increase the ripening rate and give fruits an attractive appearance, they significantly affect the organoleptic properties, such as aroma and flavour. Artificially ripened mangoes are less juicy, have uniform colour, are less tasty, difficult to cut, and have a shorter shelf life.
Calcium carbide, being an industrial-grade product, contains traces of arsenic, lead particles, and phosphorus hydride as impurities. These impurities pose serious health risks to workers handling these chemicals. Health hazards include frequent thirst, mouth and nose irritation, weakness, permanent skin damage, difficulty swallowing, vomiting, and skin ulcers. Higher exposure can lead to fluid buildup in the lungs (pulmonary edema). Acetylene released by calcium carbide adversely affects the neurological system, reducing oxygen supply to the brain and causing prolonged hypoxia. It is especially hazardous to pregnant women and children, causing headaches, dizziness, mood disturbances, mental confusion, memory loss, cerebral edema, drowsiness, and seizures.
Calcium carbide’s alkaline nature can erode mucosal tissue in the abdominal region and disrupt intestinal functions. Recent reports indicate stomach upsets after consuming carbide-ripened mangoes. Eating such fruits can lead to sleeping disorders, mouth ulcers, skin rashes, renal problems, and possibly cancer. Symptoms of poisoning include diarrhea (with or without blood), burning or tingling sensations in the abdomen and chest, difficulty swallowing, eye and skin irritation, sore throat, cough, shortness of breath, and numbness.
Ethylene is the main chemical used to speed up the ripening process, but chemicals like Ethephon and calcium carbide are regularly used due to their easy availability and low cost. Handling such chemical agents without proper precautions can be hazardous for workers. Artificially ripened fruits can cause health problems, including liver and kidney diseases, gastrointestinal irritation with nausea, cardiac disturbances, and central nervous system depression.
It is essential to analyse their effects on fruit quality and nutritional value to understand their health impact better. This critical issue requires the involvement of government agencies, policymakers, farmers, fruit vendors, scientists, and consumers to develop safer ripening practices.
