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Monitoring of prion programs in steam sterilization processes at 134°C ≥ 18 min

Prion programs are used in steam sterilization programs at 134°C; 18 min to prevent disease transmission e. g. Creutzfeld-Jakob disease, which is transmitted by prions.

Two important physical parameters have to be monitored in prion sterilization processes:

  • 1. Temperature time window (134°C; ≥ 18 min)
  • 2. Steam penetration inside instruments that have to be sterile.

gke offers batch monitoring systems (BMS) consisting of a process challenge device (PCD) and an integrating indicator strip inside.
gke PCDs are designed as hollow devices and simulate complex instruments. A chemical indicator strip is placed into the PCD and gives the information of steam penetration at the most difficult position inside of the sterilization load by changing its color to black. Additionally the color change assures that the temperature time window has been achieved.

Batch monitoring systems are able to detect non condensable gases (NCG) which easily accumulate in hollow instruments. Volumes below 1 ml are critical to prove successful sterilization in minimal invasive surgical (MIS) instruments.

The standard gke batch monitoring systems consist of PCD and integrating indicator strips and monitor the common temperature-time-window of 121°C; 15 min (F0 = 15 min) or 134°C; 3 min where all traditional pathogenic germs are killed. The construction of the PCD proves steam penetration inside hollow instruments. Longer sterilization times up to 18 min can be recorded by the sterilizer itself.

However some countries, e. g. Switzerland and France, exclusively require prion programs for all sterilization processes used. Therefore gke offers special indicators strips according to EN ISO 11140-1 class 6 (package monitoring) and class 2 (consisting of PCD and indicator strip) that are designed for 134°C; 18 min.

gke recommends to monitor steam sterilization processes with prion programs as follows:

  • 1. gke batch monitoring systems should be used to monitor sufficient air removal and steam penetration at the most difficult position inside of the sterilization load.
  • 2. Physical data such as temperature and time should be recorded by the sterilizer.
  • 3. If the sterilizer does not record the physical data or prion programs are exclusively used, the gke chemical indicator for 134°C; 18 min inside the PCD should be used.
    • The Bowie-Dick-Test has a defined temperature-time standard (Stated Value = 134°C; 3.5 min) and does not require a special indicator for prion programs.