微生物灭活型式试验是环氧乙烷灭菌器的关键性能鉴定, 特别适用于 B 类设备. 这种半循环方法使用过程挑战设备 (聚晶金刚石) 和生物指标来验证灭菌器能否达到无菌保证水平 (萨尔) 最坏情况下为 10⁻⁶. 此处描述的过程符合以下验证要求： 工业环氧乙烷灭菌器 专为医疗器械加工而设计.

所需设备和材料

The following items are necessary to perform the type test correctly:

• Process Challenge Devices (聚晶金刚石): Four identical units. Each PCD consists of a stainless steel tube and a semi‑closed chamber that holds the biological indicator. The chamber lid or opening uses an O‑ring seal and threaded connection to ensure the only gas pathway is through the tube length. The tube has a nominal length of 4.55 米, an inner diameter of 3.0 毫米 (length‑to‑diameter ratio 1500:1), giving a total internal volume of approximately 32 mL, of which the chamber volume is 0.85 mL.
• Pouches: Eight paper‑plastic pouches conforming to GB/T 19633.1, 国标/T 19633.2, YY/T 0698.4, and YY/T 0698.5.
• 生物指标: Spore strips or self‑contained indicators complying with GB 18281.1 and GB 18281.2, 通常 萎缩芽孢杆菌 spores for EO sterilization.
• Recovery Medium: Appropriate growth medium specified by the biological indicator manufacturer.
• Incubator: Calibrated to the temperature required for the biological indicator.

Test Procedure (Half‑Cycle Method)

Follow these steps systematically. All biological indicators must be from the same batch, and a positive control must be included in each test run.

步 1 – Preparation of PCDs

Place one biological indicator inside the test chamber of each process challenge device. Double‑wrap each PCD in two paper‑plastic pouches, sealing each pouch individually with a heat sealer. The double wrapping increases the challenge for the sterilant to penetrate.

步 2 – Conditioning

No preconditioning of the PCDs is required. 然而, they must be kept at 20°C ±5°C for at least one hour before the test. This simulates the worst‑case cold start condition, 使灭菌剂更难到达孢子.

步 3 – 加载和循环启动

将灭菌器预热至正常灭菌温度. 将所有四个包裹的 PCD 装入腔室并在 15 加载分钟数. 灭菌剂暴露时间必须设置为 标称曝光时间的一半 被测灭菌周期. 所有其他循环参数 (温度, 湿度, 压力) 保持不变.

步 4 – 循环后处理

循环结束后, 从灭菌器中取出 PCD. 从 PCD 室中无菌提取生物指示剂并将其转移到恢复介质中. 根据制造商的说明进行孵育, 以及同批次的未灭菌阳性对照.

步 5 - 解释

如果阳性对照显示可行的生长, the test is valid. All biological indicators from the half‑cycle exposure must show no growth. If any test indicator shows growth, the test fails, indicating insufficient lethality. Repeat the complete procedure two more times (three runs total). Consistent inactivation across all three runs confirms the sterilizer’s microbial performance capability.

Applicability and Limitations

This type test is mandatory for Class B sterilizers but can also be applied to Class A sterilizers with pre‑set programs. 然而, for Class A equipment, the type test does not replace a full performance qualification (质子Q) under actual load conditions. Always refer to the manufacturer’s validation master plan and relevant regulatory standards when implementing this protocol.