Safe storage guidelines for industrial hemp (Cannabis sativa) seeds

Abstract

Canada produced 33,750 tonnes of hemp seed over 2013-2015 on approximately 36,500 hectares in the prairie provinces. The Canadian grain industry lacks a specific guideline for safe storage of hemp (Cannabis sativa) seeds used by farmers, industry people and throughout the world especially in Canada where it grows well. A popular variety of hemp seed known as FINOLA® - was obtained from a farm in Southern Manitoba for this study. Four independent factors were considered as follows: dockage percentages, relative humidities, temperatures, and storage periods. To develop a safe storage guideline, the hemp seed with different dockage percentages (0%, 5%, and 15%) in different relative humidities maintained by salt solutions (KNO3, NaCl, NaNO2, Mg(NO3)2) were stored at different temperatures (20, 25, 30, and 35℃) for 26 weeks. The indices of spoilage in hemp seed were seed germination, FAV (free fatty acid value), visible and invisible mold, seed plate (bacteria) count, and internal green and yellow seed count. Germination of the hemp seed was significantly different at different percentages of dockages (0, 5, and 15%) as dockage may have held some unbound water that degraded the seed quality. But dockage percentages did not significantly influence equilibrium moisture content, FAV, visible and invisible mold, seed plate (bacteria) count, and internal green and yellow seed count. Hemp seed with 15% dockage had faster germination loss. Hemp seed with lower RH and temperatures had the lowest FAV, mold, seed plate count, and internal green and yellow seed count. Based on the 20% initial germination loss, hemp seed could be safely stored at ≤25℃ and ≤70%RH, which would be at ≤10% equilibrium moisture content, for more than 26 wk.