Irradiation often sparks debate. Some picture nuclear fallout; others imagine products left “radioactive” after treatment. Neither reflects the reality of modern, regulated sterilisation in healthcare manufacturing.
At Dalgety, we believe in transparency, scientific integrity, and regulatory compliance. So let’s clear the air on electron-beam (e-beam) vs gamma irradiation; what they are, why they differ, and what global regulators actually say about safety.
| Feature | E-Beam | Gamma (Cobalt-60) |
| Source | High-energy electrons from a machine; no radioactive material | Radioactive cobalt-60 isotope, continuously emitting gamma rays |
| Residual radioactivity | None. Switch off → process stops | Source is always “on” → heavy shielding, security & disposal |
| Dose delivery speed | Very fast (seconds) → high dose-rate | Slower (minutes to hours) → low dose-rate |
| Penetration | Limited depth → best for moderate density products | Very deep penetration → ideal for large, dense loads |
| Regulatory acceptance | ISO 11137, FDA, EMA, Ph. Eur. etc. | Same standards apply |
Key point: Both achieve sterilisation when validated. But their physics, process behaviours, and practicalities differ with consequences for dose control, quality, and operational risks.
Myth vs Fact: E-Beam Safety
| Myth | Fact |
| “Irradiation makes products radioactive” | E-beam uses no radioactive material; the process stops when powered down. |
| “E-beam hasn’t been tested for human use” | Used for medical devices and pharmaceuticals under ISO 11137, FDA, EMA and CDC oversight for decades. |
| “Radiation ruins product quality” | At low validated doses, effects on actives, excipients, packaging and organoleptics are minimal and well-characterised. |
| “Gamma and e-beam are basically the same” | Both sterilise, but differ in dose-rate, penetration, security risks and practicalities. |
Why Dose (and Dose-Rate) Matter
- Typical sterilisation doses: 15–35 kGy (can be used for cannabis treatment)
- Bioburden reduction doses: ≤10 kGy (preferred range used for cannabis flower)
- Regulatory principle: use the lowest validated dose that achieves sterility assurance.
E-beam’s fast dose-rate means less exposure time, reducing opportunities for degradation, important for sensitive cannabinoids and terpenes.
Because gamma delivers the same total dose at a slower rate, time-dependent reactions (e.g., oxidation) can be greater unless packaging and oxygen control are tightly optimised.
Why Gamma Persists Despite Its Challenges
Gamma requires:
- Radioactive source handling, licensing, security
- End-of-life isotope management
- Continuous safety and shielding oversight
Yet it remains in use because:
- Deep penetration handles thick, dense, or palletised products with fewer dose-mapping headaches.
- Legacy validations: decades of data and supplier infrastructure exist for gamma-treated products.
- Incremental capacity: historically easy to expand by adding cobalt-60 sources.
But cobalt-60 supply is tightening, and regulators now encourage modalities like e-beam and X-ray to improve resilience and sustainability.
Cannabis Medicines: Why E-Beam is Often Ideal
For pharmaceutical cannabis:
- Goal: Bioburden reduction or terminal sterilisation while preserving actives, aroma, and safety.
- E-beam at low doses, typically achieves microbial compliance with minimal quality impact.
- Dose mapping ensures uniform treatment without overdosing delicate plant materials.
Gamma may still be chosen for very dense packaging formats, but carries higher operational burdens and slower dose delivery.
Regulatory Evidence: Not Just Food Safety
- ISO 11137 covers gamma, e-beam, X-ray for medical devices and pharma products.
- EMA/Ph. Eur. list radiation among accepted sterilisation methods for medicinal products.
- CDC confirms ionising radiation sterilises medical products, pharmaceuticals, and tissues.
- PDA Journal reviews detail pharmaceutical excipients safely irradiated by e-beam.
These are not new technologies. They are established, regulated, and validated worldwide.
Quick FAQ
Q: Does irradiation make cannabis radioactive?
A: No. E-beam and X-ray use no radioactive source; gamma uses cobalt-60 but does not make the product radioactive either.
Q: Will irradiation change cannabinoids or terpenes?
A: Used correctly, irradiation reduces microbes without materially altering the product
Q: Why not always use e-beam if it’s simpler?
A: For very thick or dense products, gamma’s penetration can help ensure dose uniformity when e-beam can’t reach internal layers efficiently. E-Beam is optimal for cannabis
Bottom Line
- E-beam is safe, regulated, and widely used for everyday food products, pharmaceuticals, medical devices, and now cannabis medicines.
- Gamma carries operational complexities but remains useful and safe for certain product geometries.
- Low, validated doses with strict GMP controls protect both patient safety and product quality.
For Dalgety, patient care means science first, compliance always and that includes choosing irradiation methods grounded in evidence, not fear.
“Non-irradiated” ≠ “non-remediated”
But here’s where things get complicated. “Non‑irradiated” doesn’t necessarily mean “non‑remediated.” In fact, in regulated medical cannabis markets like the UK, every batch must pass stringent microbial safety standards. If the near sterile standards cannot be hit consistently (which is unsurprising, as the environment is ideal for mould to grow) remediation is essential and it could involve ozone, UV light, heat, radiofrequency, or indeed other treatments. It just might not involve ionised irradiation and as such simply isn’t disclosed.
Common Remediation Methods
- Ozone Gas
- Kills microbes via oxidation. No chemical residue.
- Pros: Penetrates tight spaces, leaves no lingering compounds.
- Cons: Can degrade aroma, needs strict worker safety protocols.
- UV‑C Light
- Surface deactivation only; misses anything internal. Good for cleaning, poor at full remediation.
- Surface deactivation only; misses anything internal. Good for cleaning, poor at full remediation.
- Radiofrequency (RF) / Cold Plasma
- RF uses heat from water molecules; cold plasma ionises gas. Both destroy pathogens, with lower sensory impact.
- Pros: Approved for organic standards, deeper reach than UV.
- Cons: Still emerging. Limited large-scale data, risk of uneven treatment.
- Heat/Pasteurisation, Washing, Chemical Gases
- These work, but often strip flavor or leave residues; some lack inhalation safety data.
- These work, but often strip flavor or leave residues; some lack inhalation safety data.
Prevention first + validated safety steps
Pharmacopoeial microbiology limits are very tight. In a living crop that loves warm, humid air, hitting those limits every time is hard, even with superb cultivation. That’s why good producers do two things:
- Prevent as much as possible (clean environment, disciplined dry/cure, monitoring)
- Use validated remediation when needed, including ionising irradiation, to bring a batch within specification before release.
Used carefully, it’s a targeted safety step in a well-run process; others may lean on high doses as a crutch for weaker cultivation and hygiene.
What good practice looks like
- Clean environment: filtered air, cleanroom habits, sanitised work areas.
- Post-harvest discipline: careful dry/cure, minimal handling, clear SOPs.
- Verification: test → remediate if required → re-test → release only if within spec.
The goal isn’t “no remediation ever”; it’s safe, compliant product with clear disclosure.
Why mould can still appear
Compliance means the batch met limits at release. Later temperature/humidity swings, storage issues, or damaged packaging can let ubiquitous airborne spores grow. That reflects post-production conditions, not necessarily cultivation quality, or whether irradiation/remediation was used.
Final thought
In a high-bar, real-world setting, prevention plus validated remediation is how you deliver consistent safety. “Non-irradiated” may be accurate, but it doesn’t necessarily mean non-remediated; other validated methods may have been used without being disclosed. Transparent process + in-spec results are what earn trust.
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.
