Fruits are naturally available food that provides various essential nutrients important to human health. Fruit consumption has increased considerably in recent years due to increased public awareness about the benefits of fruit intake and their year round availability. However, it is crucial to be aware of the hidden dangers posed by chemical ripeners used in ripening of fruits. Fruits like mangoes, bananas and many others, for instance, continue to ripen after harvest. Therefore, they are often picked while still hard and green and then artificially ripened later at or near the site of their sale to avoid the bruising and spoilage during transport. However, the residues of these artificial ripening agents and their associated impurities can pose significant health risks if used haphazardly.
Understanding the Fruit Ripening Process Natural Ripening
Naturally, fruits undergo ripening through physiological changes driven by the release of ethylene, a ripening hormone and influenced by factors such as humidity, temperature, and atmospheric gaseous composition. Ripening leads to changes in colour, sugar content, acidity, texture, and aroma of the fruit. In general, it is a process which makes the fruit edible, palatable and nutritious. Based on the ripening pattern, fruits are classified into two categories: 1). Climacteric fruits: These fruits are usually harvested once they have reached their full maturity and can be further ripened during transit or storage. These include mango, banana, apple, guava, pears, avocado, apricots, peach, tomato etc. 2). Non-climacteric fruits: These fruits do not ripen after harvest. Thus, these fruits are often harvested once they have fully matured and ripened. These include lemons, orange, grape, cherry, pineapple, strawberry etc.
Artificial Ripening
Artificial ripening is a controlled process used to enhance the ripening characteristics of climacteric fruits such as mangoes, papayas, and bananas. The primary goals are to improve consumer acceptance and boost sales by ensuring that fruits ripen faster and more uniformly. This technique is particularly useful for fruits transported over long distances, as they are picked unripe to minimize damage during transit and then ripened artificially at the destination market. Worldwide, when safe ripening agents and proper procedures are used, artificially ripened fruits are deemed safe for consumption.
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For artificial ripening, a widely used chemical is industrial grade calcium carbide (CaC2) which releases acetylene that mimics the function of natural ripening hormone ethylene. Research has shown that calcium carbide contains traces of arsenic and phosphorus hydride which are highly toxic to humans. Consuming fruits ripened using calcium carbide can cause vomiting, diarrhea, burning sensation of the chest and abdomen as these are the early symptoms of arsenic or phosphorus poisoning. Long term consumption of these fruits may increase the chances of cancer. Therefore, use of calcium carbide in fruit ripening is banned in Europe, India, Bangladesh, Nepal and many South Asian countries.
Selling or holding of fruits ripened artificially from carbide is prohibited according to Food Regulation Act, 2027 (B.S.) and this act is enforced by the Department of Food Technology and Quality Control (DFTQC) under the Ministry of Agriculture and Livestock Development. Fruits ripened with banned artificial chemical ripening agents are considered as adulterated foods and anyone holding or using such chemicals to ripen fruits can be charged from Rs 50,000 to Rs 500,000- or one-year imprisonment or both.
The other widely used chemical ripener is Ethephon which is sold under the trade name Ethrel. It releases ethylene after coming in contact with fruits thereby acting as an artificial ripener. However, recent studies published in multiple journals suggest negative impacts of ethephon on liver and reproductive systems in mice. Moreover, it causes severe skin and eye irritation on contact. UN FAO specification and evaluation on ethephon shows that industrially available ethephon also has 1,2-dichloroethane as a potential impurity which is classified as category 1B carcinogen, meaning, it has potential to cause cancer in humans. These health risks are particularly concerning due to the indiscriminate use of ethephon by many fruit vendors, who dip fruits directly into the chemical.
Note for the Vendors/Fruit Sellers: How to Safely Use Artificial Ripener?
Various health risks associated with artificial ripener like ethephon can be completely avoided by using it in a safer way. Ethephon reacts with alkali like aluminum hydroxide or sodium hydroxide releasing ethylene gas. The released ethylene gas can be used to ripen the fruits without having the need to bring ethephon in direct contact with fruits. Generally, 0.5 gm of alkali is mixed with 2 ml of commercially available ethephon (39% SL) for every 1 cubic meter of air tight room / ripening chamber in an open mouth container for 12-24 hours which results in uniform ripening of the fruits. Another aspect of safe usage of artificial ripener is to avoid using these chemicals on non-climacteric fruits such as orange, grape, cherry, pineapple, strawberry etc. as these fruits do not ripen further after harvest and must be harvested only after they are fully ripened on the trees/vines/bush. Any attempt by the vendors/fruit seller to apply artificial ripener on these fruits only increase the unnecessary risk of chemical exposure to both the workers as well as consumer
Role of government to safeguard the health of consumers
To effectively safeguard consumers’ health from improperly ripened fruits, the Department of Food Technology and Quality Control (DFTQC) should strictly monitor the improper usage of ethephon by the fruit vendors and also educate them about the correct way of its usage and its negative impact on human health. Government surveillance efforts should be increased by strengthening DFTQC’s competent manpower and research facility, increasing fruit sampling frequency, rigorously monitoring import of chemical ripeners, and screening imported fruits at customs checkpoints for the traces of harmful chemicals. Government should provide crucial support to farmers, traders and vendors for post-harvest management by establishing facilities such as cold storage, controlled atmosphere storage, and ethylene ripening facilities and by creating and disseminating awareness programs to fruit vendors about food safety standards to be followed during artificial ripening.
Note for the Consumers
As a consumer, it is important to be aware of the potential danger of artificial ripening agents and make informed choices about the fruits we consume. By choosing fruits ripened through safer methods, we can avoid the health hazards associated with indiscriminate use of artificial ripeners. As it is very difficult for a consumer to distinguish between fruits ripened following the food safety standards from the ones that are physically treated with chemicals, it is sensible to purchase fruits from known sellers/fruit dealers/ vendors who declare that their fruits are ripened using permitted chemicals and following internationally acceptable procedures. In any case one should always wash and peel the fruits before consuming. As a consumer, it is your right to inquire about the ripening techniques used by the vendor and complain to authorities like DFTQC or the police if you find any kind of health discomfort after consuming the fruits.
(Dr. Sangram Singh Pant is a PhD from the National University of Singapore, Ex-Assistant Professor of Genetics at Department of Genetics and Plant Breeding, Madhesh Agricultural University and Biotechnology/Biochemistry Subject Committee member at Faculty of Science, Purbanchal University. Pranish Tiwari is a Biotechnology graduate from Kathmandu University and currently a Teaching Assistant at Department of Biotechnology, Kathmandu University.)
