Towards a test to verify that wood has been heat-treated to the ISPM15 standard

Abstract

International trade of wood, including dunnage, is a well-known pathway for spreading diseases and wood-boring insects between countries. To mitigate this risk, the International Standard for Phytosanitary Measures No. 15 (ISPM15) states that wood packaging materials must be heated to a minimum of 56°C for 30 min. However, it is difficult to confirm that wood has been properly heat-treated. After preliminary investigations of 12 enzymes and 3 sugars from pine xylem, experiments focused on malate dehydrogenase (MDH) and fructose. Samples from the surfaces of heat-treated Pinus radiata wood exhibited decreased MDH activity and increased fructose concentration. However, samples from 5 mm deeper in the profile of heated wood showed similar MDH activity to unheated wood, but contained relatively lower fructose concentrations. There is potential to exploit heat-induced changes in MDH activity and fructose concentration to develop a quick, easily-used assay for verifying compliance of wood packaging materials with ISPM15.