Use of X-ray Irradiation for Inactivation of Aspergillus in Cannabis Flower

California cannabis regulations require testing for four pathogenic species of Aspergillus-A. niger, A. flavus, A. fumigatus and A. terreus in cannabis flower and cannabis inhalable products. These four pathogenic species of Aspergillus are important human pathogens and their presence in cannabis flower and cannabis products may pose a threat to human health. In this study, we examined the potential of X-ray irradiation for inactivation of cannabis flower contaminated with any of the four pathogenic species of Aspergillus. We determined that X-ray irradiation at a dose of 2.5 kGy is capable of rendering Aspergillus cells non-viable at low (102 spores/g dried flower), medium (103 spores/g dried flower) and high (104 spores/g dried flower) levels of inoculation. We also showed that X-ray treatment of cannabis flower did not significantly alter the cannabinoid or the terpene profiles of the flower samples. Therefore, X-ray irradiation may be a feasible method for Aspergillus decontamination of cannabis flower. More work is required to determine the consumer safety of irradiated cannabis flower and cannabis products.