As cannabis becomes a globally traded medical commodity, cGMP compliance is reshaping how it is grown, handled, and transported. For operators working with imported biomass, controlling contamination and ensuring consistency across supply chains has become a defining challenge. That challenge was a central focus at the International Cannabis Business Conference in Berlin, where a panel on Good Manufacturing Practices (GMP) examined how operators can meet the European Union’s stringent standards for medical cannabis.
Moderated by Constant Ma, CEO & President of Cannactions Consulting Ltd., the session brought together cultivators, scientists, and technology providers to discuss contamination risk from cultivation through post-harvest processing and packaging.
Unlike many agricultural commodities, cannabis presents a distinct compliance challenge. It is a biological product, inherently variable from batch to batch, and highly susceptible to microbial contamination. In medical markets, particularly in Europe, variability must be tightly controlled.
“All of this is super important because with GMP, we have to make sure that our products are consistent at all times,” Ma said. “And we also have to make sure that it’s safe for the patients that are using it.”
Where Contamination Risk Begins
Panelists emphasized that contamination risk does not begin in processing. It starts in cultivation and carries through every stage of production.
Matthieu van der Born, CEO & Founder of Flower Power, is transitioning operations from Good Agricultural and Collection Practices (GACP) to GMP, pointing to labor-intensive processes such as hand-trimming as a source of risk. High personnel density increases touchpoints, while environmental systems must account for both plant material and human activity.
Rui Soares, CEO of Paralab Green, stressed that early-stage decisions, including facility design, nutrients, and environmental controls, have lasting downstream impacts. “If you invest for quantity and not for quality, you have no future,” he said, reinforcing a recurring theme: contamination is often the result of upstream compromises.
The Critical Window: Post-Harvest
The discussion turned to post-harvest handling, widely viewed as the most vulnerable phase for microbial growth. Ed Wells, Vice President of Sales at Cannatrol, framed the issue as a risk management matter. “At the heart of GMP, you are identifying risk, then you’ve got to mitigate that risk so you have safe and predictable outcomes,” he said.
Once cannabis is harvested, microbial populations can expand rapidly if environmental conditions are not tightly controlled. The key variable is water activity: the moisture available to support microbial growth. Until the product reaches shelf stability, microbial load can continue to increase.
“The name of the game is to provide an environment where that flower becomes shelf stable as soon as possible,” Wells said. “That is your window of risk.”
That window is shaped by both process design and operations. Traditional methods, such as hanging whole plants, can extend drying time and prolong exposure. More controlled approaches, such as reducing biomass earlier and optimizing environmental conditions, can shorten that timeline, though they may require greater coordination of labor.
Joseph Edwards, Chief Scientist & Vice President of Deconix, described post-harvest cannabis as a “parasitic host relationship,” where microbial organisms continue to thrive on plant material. Without precise control of humidity, temperature, and airflow, the risk of contamination escalates quickly.
Decontamination vs. Prevention
A central tension in GMP compliance is the role of decontamination. While remediation technologies are widely used, panelists agreed they should not be the primary line of defense. Soares emphasized that microbial reduction should not be treated as a default step, but as a corrective measure when prevention fails, aligning with GMP principles that prioritize process control over downstream intervention.
Still, decontamination remains necessary when microbial levels exceed thresholds. George Terry, Executive Vice President of Rad Source, noted that technologies such as X-ray-based systems can help ensure compliance, particularly for export into regulated markets. The broader takeaway is that GMP compliance relies on layered controls: facility design, environmental management, operational discipline, and, when needed, remediation.
Planning, Cost, and Differentiation
The panel also addressed the economic realities of GMP compliance. Building a compliant facility requires significant upfront investment, and poor planning can lead to costly retrofits.
“Don’t set yourself up to have to spend good money after bad,” Wells said, advising operators to prioritize systems that improve both product quality and operational efficiency.
As markets mature and pricing compresses, differentiation becomes critical. Consistency—delivering the same product profile batch after batch—was repeatedly cited as a competitive advantage, particularly in medical markets where patients rely on predictable outcomes.
Panelists drew comparisons to pharmaceuticals and consumer goods, where consistency is non-negotiable. Variability in a medical product would be unacceptable.
A Maturing Standard
The discussion reflects an industry in transition. While GMP standards are well established in pharmaceuticals, their application to cannabis is still evolving, shaped by regulation and the biological complexity of the plant.
What is clear is that expectations are rising, especially in Europe. As more markets adopt GMP requirements, operators must approach cultivation, processing, and quality assurance as an integrated system rather than discrete steps.
For medical cannabis, patient safety, product consistency, and regulatory compliance are no longer aspirational. They are baseline requirements. And as the panel made clear, meeting those requirements begins long before the product reaches the patient.
