Dr. W. U. Faerber Institution for Hospital
Dr. F. Tilkas Hygiene and Infection
Prof. Dr. med. B.Wille Control GbR
Reg. Nr.: EQ-Zert 97224-03

IKI, P.O. Box 10 10 63, 36340 Giessen

Evaluation for hot-air-sterilization of grip pieces with end tube

On this day, 10/22/2003 we received 4 grip pieces with end tubes for evaluation whether or not they can be effectively sterilized using the hot-air-sterilization process.

Below the description on how we conducted the evaluations:

  1. Used was one hot-air-sterilization piece, manufactured by Heraeus, with rotating air, chamber size 40 cm x 40 cm x 60 cm. The piece has a timer and temperature regulator for a range of time up to 240 minutes and 260 degree Celsius, which can be chosen freely.
  2. For the microbiology testing of the sterilization effect the following spores were used. Spores taken from bacillus subtillis (niger), manufacturer is the company BAG, Lich, Order No.: 7481, Lot: B, sub-278 P 6/expiration date 2005-07-14, were used.
  3. The grip pieces with end tubing were prepped to the effect, that the bio indicators were removed, under aseptic circumstances, from their packaging and were introduced into the middle of the inner Lumina of the grip piece. Following this step they were introduced into a sterilizing hose foil for hot air, 10 cm wide, Vendor: Company Megro, Order No.: MEG 360100. In this condition the sterilization process was conducted.
  4. The trials were conducted by LTA R. Mueller in accordance with the prepared evaluation script in cooperation with the evaluation leader (Prof. Dr. med. B. Wille)
  5. Beginning of trial started on October 29th 2003 at 7.05 and ended ton November 3rd, 2003. The following temperature/time spans, in relation to each other, were used:
    160 degree C/ 20 minutes
    160 degree C/ 30 minutes
    160 degree C/ 45 minutes
    180 degree C/ 20 minutes
    180 degree C/ 30 minutes
    180 degree C/ 45 minutes
    200 degree C/ 10 minutes
    200 degree C/ 20 minutes
    200 degree C/ 30 minutes
  6. After the completion of the sterilization on each run the instrument was cooled down to around 70 – 80 degree C. Subsequently the packages with the grip pieces and bio indicators were removed, transported to a sterile workbench, the packages were opened and the indicators removed from the grip pieces by upfront-sterilized equipment (180 degree C/ 45 minutes) and immediately introduced into a Thioglykolat-Boullion.
    This Thioglykolat-Boullion was incubated for 10 days at 52+-2degree C. In so far as the tubes stayed clear the result could be qualified as “successfully sterilized”. In so far as the tubes clouded during the 10-day period the result could be qualified at “not successfully sterilized”.
  7. Every trial was processed 3 times.

Results: (see Tables 1 - 9)

At 160 degree C, and incubation time of 45 minutes a “successful sterilization” was not possible.
At 180 degree C and incubation time of 45 minutes, all bio indicators were sterile in all three runs.
At 200 degree C and incubation time of 30 minutes a successful sterilization was accomplished, however a small growth was found on the retractor of the grip piece

IN SUMMARY:
A “successful sterilization” of the grip pieces with end tubes left in our possession at the following sterilization temperature/time:

180 degree C, incubation time 45 minutes and
200-degree C, incubation time 30 minutes.

It is therefore possible to achieve an effective sterilization of grip pieces with end tubes with these temperature/time spans.

Signed:
Prof. Dr. med. B. Wille

Table 1
Date: 29.10.2003
Temperature 160 degree C
Time: 20 minutes
run grip pieces
1 2 3 4
1 + + + +
2 + + + +
3 + + + +
Control +
legend: + growth
- no growth
Table 2
Date: 29.10.2003
Temperature 160 degree C
Time: 30 minutes
run grip pieces
1 2 3 4
1 + + + +
2 + + + +
3 + + + +
Control +
legend: + growth
- no growth
Table 3
Date: 29.10.2003
Temperature 160 degree C
Time: 45 minutes
run grip pieces
1 2 3 4
1 - - - -
2 - + + -
3 - - - -
Control +
legend: + growth
- no growth
Table 4
Date: 10/30 and 31 2003
Temperature 180 degree C
Time: 20 minutes
run grip pieces
1 2 3 4
1 + + + +
2 + + + +
3 + + + +
Control +
legend: + growth
- no growth
Table 5
Date: 10/30 and 31 2003
Temperature 180 degree C
Time: 30 minutes
run grip pieces
1 2 3 4
1 + + + +
2 + + + +
3 + + + +
Control +
legend: + growth
- no growth
Table 6
Date: 10/30 and 31 2003
Temperature 180 degree C
Time: 45 minutes
run grip pieces
1 2 3 4
1 - - - -
2 - - - -
3 - - - -
Control +
legend: + growth
- no growth
Table 7
Date: 03.11.2003
Temperature 200 degree C
Time: 10 minutes
run grip pieces
1 2 3 4
1 + + + +
2 + + + +
3 + + + +
Control +
legend: + growth
- no growth
Table 8
Date: 03.11.2003
Temperature 200 degree C
Time: 20 minutes
run grip pieces
1 2 3 4
1 + + + +
2 + + - +
3 + + - +
Control +
legend: + growth
- no growth
Table 9
Date: 03.11.2003
Temperature 200 degree C
Time: 30 minutes
run grip pieces
1 2 3 4
1 - - + -
2 - - - -
3 - - - -
Control +
legend: + growth
- no growth

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