Safe to handle

Mangoes being ripened in a Filipino wet market. (Photo: Daryl Joyce)

The Philippines stands to benefit from an Australian invention that is vastly improving the way fruit is ripened for market

Easily bruised, fast-to-spoil fruit such as mangoes and bananas require relatively
sophisticated post-harvest handling processes to reach consumers in a high-quality, ready-to-eat state. Typically, the fruit is harvested mature green, making it more resilient during transport and storage. Before reaching consumers, the fruit is triggered to undergo ripening.

This involves exposing fruit to a gas that induces the same cellular changes triggered by the natural plant hormone ethylene. In the Philippines, wet market workers use calcium carbide powder to ripen fruit, but the chemical has proven problematic.

Professor Daryl Joyce, a post-harvest horticulture scientist at the University of Queensland and the Queensland Department of Agriculture and Fisheries, explains that while calcium carbide is very convenient for fruit stall owners, the chemical has been banned in many countries, and for good reasons. “Calcium carbide is considered hazardous to the workers who ripen the fruit,” he says.

“It produces an ethylene analogue, acetylene, which is unsafe to breathe as it reduces oxygen supply to the brain. Also, industrial preparations are not safe to handle, as they are typically contaminated by phosphorous hydride and arsenic.”