ISO 22256:2020

Overview

ISO 22256:2020 is an international standard that defines a method for detecting irradiation in traditional Chinese medicinal natural products using photostimulated luminescence (PSL). This standard is essential for ensuring the authenticity and safety of raw and processed Chinese medicinal materials by identifying whether they have been exposed to ionizing radiation such as gamma rays, X-rays, or electron beams. The method is applicable mainly to solid forms of medicinal products containing crushed natural materials and excludes liquid or partially solid extracts without direct solid material content.

The adoption of this standard helps regulatory bodies, manufacturers, and traders to monitor and verify the radiation status of traditional Chinese medicine (TCM) products. Through reliable detection, ISO 22256:2020 supports compliance with international trade regulations and prevents the use of irradiated materials, thereby maintaining product quality.

Key Topics

• Photostimulated Luminescence (PSL) Method: Utilizes light stimulation to release trapped energy stored in minerals like silicates and calcite present in medicinal products, resulting in luminescence detectable by specialized instruments.
• Sample Preparation: Grinding natural product samples to a fine powder with specific sample mass (typically 2 grams) placed in standardized Petri dishes for uniform testing.
• Instrument Calibration: Includes operational parameters such as acquisition frequency, dark count limits, and use of positive and negative irradiated reference materials for accurate measurement.
• Screening and Confirmation: The method consists of a two-step approach-initial screening PSL measurement followed by calibrated PSL post-irradiation with a known radiation dose to calculate the F-factor.
• Result Interpretation: F-factor (ratio of calibrated PSL to screening PSL) is critical to categorize samples as irradiated or non-irradiated, minimizing false positives by requiring repeated analysis if results are borderline.
• Limitations: Not applicable to liquid dosage forms or solid extracts lacking crushed materials; sample handling guidelines are provided to avoid contamination and sample degradation.

Applications

ISO 22256:2020 is designed primarily for:

• Regulatory Authorities: To enforce radiation restrictions on traditional Chinese medicine products and ensure compliance with safety regulations.
• Manufacturing Quality Control: Enabling manufacturers to verify the radiation status of raw materials and finished solid dosage forms, ensuring product integrity.
• Customs and Import Inspection: Providing inspection agencies with a rapid, cost-effective screening method to identify irradiated TCM products and prevent unauthorized imports.
• Research and Development: Assisting in the development of non-irradiated processing techniques by confirming irradiation status.
• International Trade: Facilitating smoother trade negotiations and reducing disputes related to non-compliant radiation treatment of natural products.

Related Standards

When implementing ISO 22256:2020, the following complementary standards may be relevant:

• EN 13751:2009 – Foodstuffs - Detection of irradiated food using photostimulated luminescence, providing foundational PSL definitions and methodologies.
• EN 1788:2001 – Foodstuffs - Thermoluminescence detection of irradiated food, useful for detecting silicate minerals isolated from foods.
• USP <2250> – Detection of irradiated dietary supplements as per the United States Pharmacopeia standards.
• Research publications such as Zhang et al. (2013) provide refined PSL criteria tailored to traditional Chinese medicinal herbs.

Keywords: ISO 22256:2020, traditional Chinese medicine, photostimulated luminescence, PSL detection, irradiated natural products, ionizing radiation detection, gamma radiation, X-ray, beam radiation, TCM product safety, radiation status identification, quality control in Chinese medicine, medicinal material irradiation, international trade compliance.