Medicinal cannabis, like any other pharmaceutical product, must meet stringent safety and quality standards, particularly for immunocompromised patients. One of the most debated methods for ensuring microbial safety is irradiation. But how does this compare to other sterilisation techniques, and why is transparency around these processes so crucial?
The Question of Transparency: Irradiation vs. Remediation
Unlike in the food industry, where irradiated products must be labelled, cannabis products are not held to the same transparency standards. While ionising irradiation (gamma, beta & X-ray) must be disclosed, other remediation methods, including cold plasma, and extended light exposure, do not require the same level of reporting. This lack of clarity leaves both prescribers and patients unaware of the full extent of processing their medicine has undergone, potentially affecting treatment choices.
The Prevalence of Irradiation and Remediation
The great majority of the medicinal cannabis products go through some form of decontamination to meet the strict safety standards required by the MHRA. Some of the most common methods of irradiation are gamma and beta irradiation. However, others such as cold plasma, X-ray, UV or other remediation techniques are also quite frequent. Each approach has its place, but the choice of method has a great impact on the quality, safety, and even the therapeutic properties of the final product. Moreover, only ionising irradiation has to be declared. Do patients and doctors really know how their medicines have been processed?
Gamma vs. Beta Irradiation: What’s the Difference?
Both gamma and beta irradiation are aimed at killing microbial contaminants but in different ways.
Gamma irradiation uses photons from a radioactive source, usually cobalt-60. It is renowned for its deep penetration and the ability to give uniform treatment to a larger batch of cannabis.The level of irradiation dose for Gamma is usually much higher than beta-irradiation and therefore best to treat products with a higher pre-treated microbial count.
Beta irradiation (also known as “e-beam”), on the other hand, uses high-energy electrons that are emitted by an electron beam (e-beam) and can therefore be controlled at a much lower dose in comparison to Gamma irradiation. This method is usually best when treating a product with a low pre-treated microbial count.
Both methods are effective; however, the choice is usually dependent on the specific needs of the batch that is being treated.
| Method | Process | Best Used For | Key Considerations |
| Gamma Irradiation | Uses Cobalt-60 to emit high-energy photons | High microbial load products | Deep penetration but higher radiation exposure |
| Beta Irradiation (E-beam) | Uses high-energy electrons for sterilisation | Lower microbial load products | More controlled dosing but less penetration |
Section 5.1.8B EU Pharmacopoeia states that for the UK the maximum count for Total Aerobic Microbial Count (TAMC) and Total Yeast and Mold Count (TYMC) is 50,000 CFU/g or CFU/mL and 500 CFU/g or CFU/mL respectively. It should be noted that in more mature markets like Canada, the maximum counts, as listed in 5.1.8C for TAMC is 500,000 cfu/g (10x greater allowance than UK) & TYMC – 50,000 cfu/g (100x greater allowance than UK).
Does the Food Industry Have It Figured Out?
Irradiation is not new to cannabis. In fact, it is already widely used in the food industry to ensure the safety of things like spices, dried fruits and some meats. However, while all foods that have been irradiated in the UK must be labelled, cannabis does not have to meet the same standards of transparency.
The Challenges of Remediation
Other remediation methods that include extended radiation exposure also have their own set of challenges:
- Duration Matters: Prolonged exposure to any form of radiation (UV, light etc) can ruin the cannabinoids and terpenes in the product, changing both how well it works and how it tastes.
- Even Distribution: It is quite challenging to achieve uniform treatment of an entire batch; some parts may be under-treated and, therefore, not achieve the bioburden reduction, leaving them potentially unsafe..
- Cultivation Practices: Some producers engage in low-quality cultivation with the attitude that remediation will clean up the product later in the process. This reactive approach can compromise the quality of the final product.
Why Remediation and Irradiation Are Still Necessary
Cannabis is grown in warm, humid conditions, akin to what they would be exposed to naturally, however these are conducive to microbial growth. To meet the safety requirements for medicinal use, particularly for high-risk patients, some form of microbial reduction is often necessary. While irradiation is a reliable method of reducing microbial load, it is most effective when combined with good cultivation practices that minimize the chances of contamination.
Some patients report differences in taste and efficacy between non-irradiated and heavily remediated cannabis due to terpene degradation.
A lack of transparency means prescribers may unknowingly recommend products that have undergone aggressive remediation, potentially altering their expected effects.
The Dalgety Perspective
At Dalgety, we prioritise patient-first approaches and transparency. By adhering to Good Manufacturing Practices (GMP) from cultivation through to supply, we significantly reduce the need for post-harvest remediation and only use a low dose of e-beam irradiation. Our UK-based operation ensures fewer handling points, faster turnaround times, fresher products, meaning patients receive a more consistent, high-quality medicine they can trust.
The Path Forward
As the medicinal cannabis industry develops, transparency will become essential for building trust. Patients and prescribers have the right to know how their medicine is grown, processed, and treated. Whatever remediation methods are used the focus must remain on safety, quality, and patient outcomes.
Disclaimer: The information provided in this blog is for educational purposes only and is intended for healthcare professionals involved in the prescribing and administration of cannabis-based medicinal products (CBMPs). It does not constitute medical advice, diagnosis, or treatment recommendations. While every effort has been made to ensure accuracy, regulatory guidelines and clinical best practices may evolve. Prescribers should refer to the latest guidance from the Medicines and Healthcare products Regulatory Agency (MHRA), the National Institute for Health and Care Excellence (NICE), and other relevant bodies when making treatment decisions. Dalgety does not endorse any specific product or treatment pathway and encourages healthcare professionals to exercise their clinical judgement in patient care.
