Disposable biological indicator test pack for monitoring steam and ethylene oxide sterilization cycles

• US 4,839,291 A
• Filed: 05/15/1987
• Issued: 06/13/1989
• Est. Priority Date: 05/15/1987
• Status: Expired due to Term

• Current Assignee: American Sterilizer Company (Steris Corporation)
• Original Assignee: American Sterilizer Company (Steris Corporation)
• Inventors: Dyke, Denis G., Welsh, Jon D.
• Primary Examiner(s): Scott, Samuel
• Assistant Examiner(s): Price, Carl D.
• Application Number:
  US07/050,585
• Time in Patent Office: 760 Days
• Field of Search: 435/287, 435/296, 435/299, 435/292, 435/293, 435/294, 435/295, 435/296, 435/311, 435/31, 206/305, 206/569
• US Class Current: 435/287.4
• CPC Class Codes: A61L 2/28 Devices for testing the effectiveness or completeness of sterilisation, e.g. indicators which change colour apparatus involving enzymes or microorganisms C12M1/34; methods involving enzymes or microorganisms C12Q1/00
• CPC Class Codes: C12Q 1/22 Testing for sterility conditions

Abstract

A disposable test pack for monitoring the efficacy of steam or ethylene oxide sterilization cycles includes a fiber board housing for a bioligical indicator. The housing includes an outer tube and a shorter inner tube. The outer tube has upper and lower portions which define a seam or gap at their adjoining open ends. The inner tube extends past the seam and telescopes into the upper and lower portions. The seam and the close tolerance between the inner tube and the upper and lower portions of the outer tube provide a tortuous path for the entry of sterilant into the interior of the housing. The tortuous path has a moisture absorbent surface and is dimensioned to promote intimate contact between the sterilant and the absorbent surface. The exterior of the housing can be lined with foil to prevent sterilant from permeating the housing, thereby preventing entry of the steam by any path other than through the seam. A hole covered by an optionally removable tab is provided at the end of the upper portion of the outer tube for use in monitoring ethylene oxide sterilization cycles.

Claims

1. A device for monitoring the efficacy of steam and ethylene oxide sterilization cycles comprising:

a housing having an interior made of a material having heat sink, insulating and moisture absorbent properties, said housing being configured to define at least one tortuous path for entry of sterilant into said housing, said tortuous path having a moisture absorbent surface and being dimensioned to promote intimate contact between said sterilant and said surface as said sterilant moves along said tortuous path;

means for optionally providing an alternate path of entry of sterilant into said housing; and

a biological indicator within said housing which includes a calibration of microbes which are resistant to sterilization by steam and ethylene oxide.

2. The device recited in claim 1 wherein said housing has an inner member and an outer member, said outer member having an upper portion and a lower portion, each said upper and lower portion having one open end in a substantially abutting relationship with said open end of said other portion to define a seam therebetween;

and

said inner member telescoping into said upper portion and into said lower portion past said seam to define at least one said tortuous path progressing through said seam, between the outer surface of said inner member and the inner surfaces of at least one of said upper and lower portions and into said housing.

3. The device recited in claim 1 wherein said means for optionally providing an alternate path of entry of sterilant is a hole in said housing and an optionally removable closure for sealing said hole until said closure is removed.

4. The device recited in claim 1 wherein said biological indicator comprises:

an ampule having one open end;

a cap for covering said open end of said ampule, said cap dimensioned to define an annular space between the interior of said cap and the exterior of said ampule to provide a second tortuous path for entry of sterilant into said ampule, said cap having two positions, one said position permitting entry of sterilant through said second tortuous path and the other said position closing said ampule;

a substrate inoculated with a calibration of bacterial spores resistant to sterilization by steam and ethylene oxide; and

an enclosed frangible vial of growth media for said spores.

5. The device recited in claim 1 further comprising a means for positioning said biological indicator within said housing.

6. The device recited in claim 5 wherein said positioning means is a carrier having a cutout section for holding said biological indicator.

7. The device recited in claim 6 wherein said carrier further comprises shock absorbing means at the ends of said carrier.

8. A device for monitoring the efficacy of steam and ethylene oxide sterilization cycles comprising:

a housing having an inner member and an outer member, said outer member having a first entryway therethrough to at least one tortuous path defined between said inner and outer members, said tortuous path having a moisture absorbent surface and being dimensioned to promote intimate contact between said sterilant and said surface as said sterilant moves along said tortuous path;

said housing having an alternate entryway therethrough;

means removably sealing said alternate entryway for optionally providing a second path of entry of sterilant into said housing; and

a biological indicator within said housing which includes a calibration of microbes which are resistant to sterilization by steam and ethylene oxide.

9. The device recited in claim 8 wherein said housing is made from a cellulosic material having heat sink, insulating and moisture and ethylene oxide absorbent properties.

10. The device recited in claim 8 wherein the exterior of said housing, excluding said first entryway, is covered with a moisture repelling material which is impermeable to steam and ethylene oxide sterilants.

11. The device recited in claim 8 wherein at least said first entryway is covered with a layer of material which is permeable to steam and ethylene oxide sterilants.

12. The device recited in claim 8 further comprising means for positioning said biological indicator.

13. The device recited in claim 12 wherein said positioning means is a carrier made of an ethylene oxide absorbent material.