Ethyl formate + nitrogen fumigant: a new, safe, and environmentally friendly option for treating a 20 ft shipping container loaded with general freight

Abstract

The use of shipping containers for cargo transportation has the potential to transport insect pests from infested to non-infested areas. Fumigation is required as an appropriate biosecurity measure to exterminate insect pests. Fumigation trials were conducted in a 20 ft general purpose (GP) shipping container. Four species of mixed-age cultures, Lasioderma serricorne (F.), Sitophilus oryzae (L.), Trogoderma variabile (Ballion), and Rhyzopertha dominica (F.) were used for bioassays. Ninety g m⁻³ of ethyl formate + nitrogen formed non-flammable ethyl formate fumigant formulation was released into the container. The fumigation yielded sufficient concentration × time (Ct) products at a range of 437.54–449.19 g h m⁻³ in the container for exterminating all life stages. Ethyl formate left no residue in treated drinks. This study demonstrated that on site generation of a non-flammable ethyl formate and nitrogen fumigant can be achieved and this new application technology ensures that ethyl formate distributes evenly in the container within 30 min after application and with a variation of <3%. The research further demonstrated that an ethyl formate + nitrogen application can be used as a pre-shipment treatment for controlling all the stages of insect pests in a shipping container. After a fumigation holding period and ventilation of 15 min, ethyl formate was successfully removed from the container at 0.5–35ppm in different locations. The levels of ethyl formate in the workspace were <0.5 ppm during application, fumigation, and aeriation, which is about 5% of the 100 ppm level for ethyl formate.

Keywords:

• Fumigation
• shipping container fumigation
• fumigant
• ethyl formate
• ethyl formate + nitrogen
• ethyl formate residue
• insect pests
• biosecurity

Acknowledgments

We thank James Newman for his help with the setup of the gas sampling lines and Yu Xiao for preparing insect samples from the Postharvest Biosecurity and Food Safety Laboratory at Murdoch University.