Sterilization monitoring method

• US 6,440,744 B1
• Filed: 01/05/2000
• Issued: 08/27/2002
• Est. Priority Date: 06/25/1997
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Ignacio, Ramon T., Piechowski, Allan P.
• Primary Examiner(s): SNAY, JEFFREY R
• Application Number:
  US09/477,859
• Time in Patent Office: 965 Days
• Field of Search: 422/86, 422/5, 422/6, 422/28, 422/87, 422/37, 422/12, 436/1, 436/164, 436/169
• US Class Current: 436/1
• 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

Abstract

A sterilization monitor includes a substrate and an monitor composition. The monitor composition contains a colorant and a halogen source and undergoes a distinct color change when exposed to a peracid. The sterilization monitor can be used to monitor a sterilization process involving a peracid. A sterilization monitoring device, including a sterilization monitor enclosed in a housing having a vapor permeable barrier, can also be used to monitor a sterilization process.

Claims

1. A method of monitoring a peracid liquid phase sterilization process, comprising

exposing a monitoring composition including a colorant and a halogen source to a peracid from a sterilization solution during a peracid liquid phase sterilization process, wherein said colorant is susceptible to halogenation by said halogen source and the composition will change to a particular color if the sterilization process meets pre-determine sterilization parameters and detecting a color change of said monitor composition.

2. The method of claim 1, wherein the predetermined sterilization parameters include exposure time.

3. The method of claim 2, wherein the exposure time is at least 1 minute.

4. The method of claim 1, wherein the predetermined sterilization parameters include exposure temperature.

5. The method of claim 4, wherein the exposure temperature is at least 25°

C.

6. The method of claim 1, wherein the predetermined sterilization parameters include concentration of a peracid in the sterilization solution.

7. The method of claim 6, wherein the exposure concentration of a peracid from a sterilization solution is at least 1000 ppm.

8. The method of claim 1, wherein the predetermined sterilization parameters include exposure time and exposure concentration of a peracid from a sterilization solution.

9. The method of claim 1, wherein the predetermined sterilization parameters include exposure temperature and exposure concentration of a peracid from a sterilization solution.

10. The method of claim 1, wherein the predetermined sterilization parameters include exposure time, exposure temperature and exposure concentration of a peracid from a sterilization solution.

11. The method of claim 10, wherein the exposure time is at least 1 minute, the exposure temperature is at least 25°

C., and the exposure concentration of a peracid from a sterilization solution is at least 1000 ppm.

12. The method of claim 11, wherein said halogenated colorant is susceptible to additional reactions which cause the monitoring composition to undergo a distinct color change that provides an indication if the sterilization process meets said pre-determined sterilization parameters.

13. The method of claim 11, wherein said halogen comprises bromine or iodine.

14. The method of claim 11, wherein the concentration of a peracid from a sterilization solution is at least 1000 ppm.

15. The method of claim 11, wherein said colorant comprises phenol red.

16. The method of claim 11, wherein said monitor composition is enclosed within a housing including a vapor permeable barrier and wherein peracid vapor passes through the barrier to contact the monitor composition and cause the halogenation.

17. A method of determining whether a liquid solution including peracetic acid has a concentration at about 2500 ppm, comprising

exposing a monitor composition, including a colorant and a halogen source, wherein said colorant is susceptible to halogenation by said halogen source, to a liquid sterilization solution including peracetic acid under conditions that will cause the composition undergo a color change at about 2500 ppm of peracetic acid and detecting a color change of said monitor composition.

18. The method of claim 17, wherein the halogen source halogenates the colorant to cause a color change in the monitor composition that provides an indication of the concentration of the peracetic acid in the solution.