As cannabis gains wider acceptance in the mainstream there is an ever growing need to ensure that consumers are receiving quality product with known potency that is free of contaminants. At present there are 33 states in the US that have legalized cannabis for medicinal use and 11 for recreational use. In this nascent industry, many aspects of how to ensure products are safe for use remain unclear. Therefore, it’s no surprise that states differ in the amount of testing and the types of testing they require before a product to goes to market. Furthermore, there is a large lack of trust in the data testing labs generate due to a lack of standardization and infrastructure to ensure testing accuracy. Reference methods are currently being developed by groups such as AOAC’s Cannabis Analytical Sciences Program (CASP) to address these interlab variances, and many labs are working towards ISO17025 accreditation in order to ensure traceability and quality analysis.
How is ISO17025 helping build confidence in lab data?
The lab has arrived at a result, but how did it get there? Who handled the sample at each point in the process, and did they follow the SOP? Were their quality control samples included in the run to demonstrate the instrument was functioning properly? Traceability is a key component of quality management systems, and some states are starting to mandate ISO17025 accreditation. ISO17025 accreditation ensures a lab is following its standard operating procedures (SOP) and can retrace their steps at any point to determine how they arrived at a particular answer. A well-architected quality management system and a capable Laboratory Information Management System (LIMS) can help labs achieve this level of traceability, while also providing legal defensibility for the lab should a consumer fall ill, or some other kind of dispute arise.
What’s considered safe in the context of pesticides?
Pesticide analysis is one area where there is a particular lack of clarity in cannabis testing. California has opted to test for 66 different pesticides while Canada has decided to test for 96 with some overlap however at significantly lower limits. Toxicological data is available for the ingestion of many of these compounds, but none of this is available for the safety of the vaporization/combustion and subsequent inhalation of these substances. This gap in our knowledge makes it very difficult to properly craft policy. Analysis for these compounds becomes even more tricky due to the high levels of interference from other molecules, such as cannabinoids as well as the variety of matrices that require this kind of testing.
Tobacco is the most similar crop to have this type of analysis performed; however, this work is hardly thorough or relevant as its use is well known to be carcinogenic regardless of pesticide prevalence. Given the unknowns with this route of administration, Canada has chosen to take a more cautious approach, essentially allowing near zero tolerance with limits as low as 0.01 ppm for some of the analytes of interest 1. AOAC’s Cannabis Analytical Sciences Program (CASP) is currently working on a reference method to address all of the compounds at the lowest action levels in both lists. That work is expected to be completed sometime in Fall of 2019.
What microbial contaminants should we be worried about?
When it comes to microbial testing requirements, there is even more disarray. Some jurisdictions only require species-specific testing for known pathogens, some require total count tests, and most require a mixture of both. This highlights the lack of consensus among regulators as to what dictates a product is safe. The Medicinal Genomics team has demonstrated that caution should be exercised when using culture-based methods for testing cannabis and cannabis products. Sequencing has demonstrated that culture-based total yeast and mold tests can detect off-target microorganisms, artificially elevating results. Additionally, some cannabis infused product matrices can affect the readout chemistry of many of these systems leading to inaccuracies in results 2.
One thing that standards organizations like AOAC have agreed upon is that pathogenic Aspergillus spp. is a primary concern for cannabis users especially in the context of inhaled products. There is an abundance of literature to support these concerns 3-6. Therefore, the AOAC CASP microbial working group has focused its efforts on the accurate detection and quantification of this pathogen in cannabis and cannabis products. The jury is still out in terms of what to make of total count tests, which are standard in many industries but cannot distinguish between pathogenic and benign organisms, potentially causing failures in cultivators who use beneficial microbes.
Where do we go from here?
To gain more standardization across laboratories, it’s imperative that standards organizations continue to step up to develop methods that allow for the accurate quantification of the analytes required in each of these jurisdictions. Additionally, achieving ISO17025 accreditation will allow for maximum traceability throughout the testing process and give distributors and producers alike more confidence in the results they receive from cannabis testing labs. Furthermore, in regard to regulations, research that provides a better understanding of what is considered safe in terms of cannabis contaminants for the various routes of administration should be paramount in order to establish guidelines that make scientific sense.
References
- Seltenrich N. Into the Weeds: Regulating Pesticides in Cannabis. Environ Health Perspect. 2019;127(4):42001.
- McKernan K, Spangler J, Helbert Y et al. Metagenomic analysis of medicinal Cannabis samples; pathogenic bacteria, toxigenic fungi, and beneficial microbes grow in culture-based yeast and mold tests [version 1; peer review: 3 approved, 1 approved with reservations]. F1000Research 2016, 5:2471 (https://doi.org/10.12688/f1000research.9662.1)
- Szyper-Kravitz M, Lang R, Manor Y, Lahav M. Early invasive pulmonary aspergillosis in a leukemia patient linked to aspergillus contaminated marijuana smoking. Leukemia & lymphoma. 2001 Nov-Dec;42(6):1433-7. PubMed PMID: 11911432.
- Marks WH, Florence L, Lieberman J, Chapman P, Howard D, Roberts P, et al. Successfully treated invasive pulmonary aspergillosis associated with smoking marijuana in a renal transplant recipient. Transplantation. 1996 Jun 27;61(12):1771-4. PubMed PMID: 8685958.
- Llamas R, Hart DR, Schneider NS. Allergic bronchopulmonary aspergillosis associated with smoking moldy marihuana. Chest. 1978 Jun;73(6):871-2. PubMed PMID: 657864.
- Hamadeh R, Ardehali A, Locksley RM, York MK. Fatal aspergillosis associated with smoking contaminated marijuana, in a marrow transplant recipient. Chest. 1988 Aug;94(2):432-3. PubMed PMID: 3293934.