MesaLabs
  • Our Solutions

    • Sterilization & Cleaning Monitoring

      • Products

        • Biological Indicators & Accessories

        • Chemical Indicators

        • Cleaning Control

        • All Products

      • Services & Consulting

        • Sterilization Cycle Development & Validation

        • Contract Laboratory Testing

      • Knowledge Center

        • Resource Library

        • White Papers

        • Training & Events

        • Videos

        • FAQs

        • Customer Support

        • Request a Quote

    • Mail-in Spore Testing

      • Products

        • Testing Services Packages

        • In-Office Testing Products

        • Chemical Indicators

        • All Products

      • Services

        • Check Test Results

      • Knowledge Center

        • State Dental Regulations

        • Industry Insights

        • FAQs

        • Customer Support

      • Shop Online

    • Continuous & Process Monitoring

      • Hardware

        • Continuous Monitoring Panels & Sensors

        • Process Monitoring Data Loggers

        • All Products

      • Software

        • Continuous Monitoring Software

        • Continuous Monitoring Software Downloads

        • Process Monitoring Software

      • Services

        • Validation & Calibration Services

        • Data Logger Calibration & Repair

      • Knowledge Center

        • Resource Library

        • FAQs

        • Customer Support

        • Request a Quote

      • Shop Online

    • Renal Care Quality Control

      • Products

        • 90XL Technician Meter

        • pHoenix XL Reference Meter

        • Solutions - Conductivity, pH, Neo Care, NIST-Traceable

        • Care & Calibration Stations

        • All Products

      • Services

        • Equipment Calibration & Repair

      • Knowledge Center

        • Resource Library

        • FAQs

        • Customer Support

        • Request a Quote

      • Shop Online

    • Occupational Health & Safety

      • Gas & Air Flow Instruments

        • Mesa Defender Series (Volumetric Accuracy ±1%)

        • Mesa FlexCal Series (Volumetric Accuracy ±0.5%)

        • Mesa BGI DryCal Metrology Series

        • All Products

      • Accessories

        • Mesa Defender Series Accessories

        • Mesa FlexCal Series Accessories

        • Mesa DryCal Pro Software

      • Services

        • Equipment Calibration & Repair

      • Knowledge Center

        • Resource Library

        • Videos

        • FAQs

        • Customer Support

        • Request a Quote

      • Shop Online

    • Environmental Controls & Air Quality

      • Equipment

        • Mesa BGI Ambient Particulate Air Samplers

        • Mesa BGI Air Flow Calibrators

        • Mesa BGI Personal Sampling Cyclones

        • Mesa BGI Environmental Cyclones

        • All Products

      • Software

        • Mesa BGI Companion Software

      • Accessories

        • Environmental Accessories

        • Industrial Hygiene Accessories

        • Filter Media

      • Services

        • Equipment Calibration & Repair

        • Equipment Rental

      • Knowledge Center

        • Resource Library

        • Videos

        • FAQs

        • Customer Support

        • Request a Quote

      • Shop Online

    • Torque Testing

      • Products

        • Semi-Automatic Torque Testers

        • Manual Torque Testers

        • All Products

      • Accessories

        • Torque Testing Accesories

      • Software

        • TorqueIQ Process Control Software

      • Services

        • Gold Bottle Magnetic Torque Verification

        • Equipment Calibration & Repair

        • Upgrade/Trade-In Options

        • Torque Rentals

      • Knowledge Center

        • Resource Library

        • Customer Support

        • Request a Quote

  • About Us

    • Our Purpose

    • Mesa Brand Family

    • Executive Team

    • Careers

    • Investor Information

  • Contact Us

  • Resource Library

    • Certificate (COA) Finder

    • Regulatory Documents

    • Instruction Manuals

    • Product Specifications

    • Product Technical Reports

    • Safety Data Sheets

  • Our Solutions

    chevron
    • Sterilization & Cleaning Monitoring

      • Products

        • Biological Indicators & Accessories

        • Chemical Indicators

        • Cleaning Control

        • All Products

      • Services & Consulting

        • Sterilization Cycle Development & Validation

        • Contract Laboratory Testing

      • Knowledge Center

        • Resource Library

        • White Papers

        • Training & Events

        • Videos

        • FAQs

        • Customer Support

        • Request a Quote

    • Mail-in Spore Testing

      • Products

        • Testing Services Packages

        • In-Office Testing Products

        • Chemical Indicators

        • All Products

      • Services

        • Check Test Results

      • Knowledge Center

        • State Dental Regulations

        • Industry Insights

        • FAQs

        • Customer Support

      • Shop Online

    • Continuous & Process Monitoring

      • Hardware

        • Continuous Monitoring Panels & Sensors

        • Process Monitoring Data Loggers

        • All Products

      • Software

        • Continuous Monitoring Software

        • Continuous Monitoring Software Downloads

        • Process Monitoring Software

      • Services

        • Validation & Calibration Services

        • Data Logger Calibration & Repair

      • Knowledge Center

        • Resource Library

        • FAQs

        • Customer Support

        • Request a Quote

      • Shop Online

    • Renal Care Quality Control

      • Products

        • 90XL Technician Meter

        • pHoenix XL Reference Meter

        • Solutions - Conductivity, pH, Neo Care, NIST-Traceable

        • Care & Calibration Stations

        • All Products

      • Services

        • Equipment Calibration & Repair

      • Knowledge Center

        • Resource Library

        • FAQs

        • Customer Support

        • Request a Quote

      • Shop Online

    • Occupational Health & Safety

      • Gas & Air Flow Instruments

        • Mesa Defender Series (Volumetric Accuracy ±1%)

        • Mesa FlexCal Series (Volumetric Accuracy ±0.5%)

        • Mesa BGI DryCal Metrology Series

        • All Products

      • Accessories

        • Mesa Defender Series Accessories

        • Mesa FlexCal Series Accessories

        • Mesa DryCal Pro Software

      • Services

        • Equipment Calibration & Repair

      • Knowledge Center

        • Resource Library

        • Videos

        • FAQs

        • Customer Support

        • Request a Quote

      • Shop Online

    • Environmental Controls & Air Quality

      • Equipment

        • Mesa BGI Ambient Particulate Air Samplers

        • Mesa BGI Air Flow Calibrators

        • Mesa BGI Personal Sampling Cyclones

        • Mesa BGI Environmental Cyclones

        • All Products

      • Software

        • Mesa BGI Companion Software

      • Accessories

        • Environmental Accessories

        • Industrial Hygiene Accessories

        • Filter Media

      • Services

        • Equipment Calibration & Repair

        • Equipment Rental

      • Knowledge Center

        • Resource Library

        • Videos

        • FAQs

        • Customer Support

        • Request a Quote

      • Shop Online

    • Torque Testing

      • Products

        • Semi-Automatic Torque Testers

        • Manual Torque Testers

        • All Products

      • Accessories

        • Torque Testing Accesories

      • Software

        • TorqueIQ Process Control Software

      • Services

        • Gold Bottle Magnetic Torque Verification

        • Equipment Calibration & Repair

        • Upgrade/Trade-In Options

        • Torque Rentals

      • Knowledge Center

        • Resource Library

        • Customer Support

        • Request a Quote

  • About Us

    chevron
    • Our Purpose

    • Mesa Brand Family

    • Executive Team

    • Careers

    • Investor Information

  • Contact Us

  • Resource Library

    chevron
    • Certificate (COA) Finder

    • Regulatory Documents

    • Instruction Manuals

    • Product Specifications

    • Product Technical Reports

    • Safety Data Sheets

White Papers

  1. Home

  2. caret-right icon

    Our Solutions

  3. caret-right icon

    Sterilization & Cleaning Monitoring

  4. caret-right icon

    Knowledge Center

  5. caret-right icon

    White Papers

  6. caret-right icon

Biological Indicator Incubation and Reduced Incubation Time (RIT)

Biological Indicator Incubation and Reduced Incubation Time (RIT)

Introduction  

Biological Indicators (BIs) are the gold standard of lethality indicators and to achieve final test results, a cultivation period is required.  Cultivation is the act of introducing the spores to a growth medium and incubating at a defined time/temperature combination. Cultivation can be relatively simple with self-contained BIs (SCBIs) or more involved with standard spore strip BIs.  SCBIs contain both the necessary growth medium and vial as on-board components allowing the act of cultivation to occur in any setting.  Spore strip BIs require additional materials (tubes of media) and resources (aseptic environment) for culturing the spores.  

Cultivating the test microorganisms is a standard microbiological practice; however, choosing an appropriate incubation period has not always been straightforward.  This period must be sufficient in length to allow surviving injured spores time for outgrowth.  In general, most labs recognize this period to be 14 days; however, the health care standards for BIs (containing widely recognized test microorganisms) have set the incubation time at 7 days.  Shorter incubation periods are allowed provided the “Reduced Incubation Time” has been validated.  There are two published validation methods available, one from the US Food and Drug Administration and the other from the International Standards Organization.    

Standards & References 

ISO 11138-1 (2017) Sterilization of health care products — Biological indicators —Part 1: General requirements

7.3.2 A reference incubation time is commonly recognized to be seven days for established sterilization processes, such as moist heat and ethylene oxide, using well characterized test organisms, such as Geobacillus stearothermophilus and Bacillus atrophaeus, respectively.

ISO 11138-7 (2019) Sterilization of health care products — Biological indicators —Part 7: Guidance for the selection, use and interpretation of results

8.2.3 The biological indicators should be removed from the sterilizer load as soon as possible after the process, without compromising the safety of personnel. They should be tested within a specified time interval that has been established for that product and process. The time intervals between preparation of the indicators and their use in the sterilization process, and between the end of the process and the culturing of the indicators should be justified in order to demonstrate that these intervals have no effect on the results of the biological testing of the sterilizer or sterilization process. These justified time intervals should not be exceeded. If the biological indicators are handled in a manner other than those stated by the manufacturer, the procedures should be validated to determine if they affect the performance of the biological indicator. Any established time intervals should be followed.

ISO 11138-7 (2019) Sterilization of health care products — Biological indicators —Part 7: Guidance for the selection, use and interpretation of results
 

Introduction. A biological indicator incubation time is the minimum period of cultivation required before making a final determination that a biological indicator is negative (shows no growth).

Scope. This document is applicable to manufacturers of biological indicators (BIs) and to end users of BIs who intend to, if required by their quality system, establish, validate or confirm a RIT.

4.4. The RIT validation for a spore strip that includes a recovery medium as a kit or a self-contained BI does not have to be repeated by the end user as long as the end user uses the BI with same sterilizing agent and BI incubation temperature as that used in the validation and used in ethylene oxide. See ISO 11138-7:2019, 12.3.3.

Guidance for Industry and FDA Staff, Biological Indicator (BI) Premarket Notification [510(k)] Submissions   

Attachment II. Examples of Validation of Biological Indicator Incubation Time

USP <55> BIOLOGICAL INDICATORS—RESISTANCE PERFORMANCE TESTS:   

Recovery. After completion of the sterilizing procedure for BIs and within a noted time (NMT 4 h), aseptically remove and add each BI to a suitable medium (see media in Sterility Tests ⟨71⟩) to submerge the BI completely in a suitable tube. For self-contained BIs, the paper strip is immersed in the self-contained medium according to manufacturers’ instructions, within a noted time NMT 4 h.

Mesa Labs’ Recommendations

1.Culturing spore strip BIs

  1. culture positive control BIs last

  2. culture BIs in controlled environment  

  3. use sterile forceps between BI units     

  4. use protective equipment (lab coat and gloves)

2. In situations where BI results cannot be read at the labeled incubation time, cultivate BIs and incubate longer.  The labeled incubation claim is a minimum time, and it is better to cultivate immediately (after treatment) than to delay cultivation in an attempt to meet the minimum incubation period.  With SCBIs where prolonged incubation may result in growth medium evaporation, the vents in the caps should be sealed.

3. Read the BI results frequently throughout incubation and then subculture any growth-positive BIs immediately to avoid death of microorganisms. 

4. It is costly and time consuming for BI users to verify labeled RIT claims.  Consider avoiding this practice unless BIs are not used in accordance with label claims.

5.The ISO standard states that the BIs should be removed and tested from the sterilizer load as soon as possible and within a specified time interval.  For BI resistance testing, Mesa has established an interval =/< ≤ 4 hours, and recommend this time period for end users. 

Additional Resources 

  1. Spore News--Reduced Incubation Time, What’s the Point? 
  2. Spore News—Sub-Culturing a Positive Biological Indicator for Identification 
  3. Spore News--Review of the Newly Released ISO 11138-8 Standard on the Validation of a Reduced Incubation Time for Biological Indicators 

SN078-V1

Topics: Ethylene Oxide ,   Reduced Incubation Time (RIT) ,   BI Selection ,   Steam ,   Dry Heat
Recent Posts
End-User or Third-Party Resistance Verification End-User or Third-Party Organism Identification and Purity Apex® EZTest®: A Self-Contained Biological Indicator for Vaporized Hydrogen Peroxide Decontamination Processes Vaporized Hydrogen Peroxide Isolator Decontamination in a World of Uncertainty: A Modern-Day Field Guide Biological Indicator Incubation and Reduced Incubation Time (RIT) Biological Indicators for Vaporized Hydrogen Peroxide Isolator Decontamination: Characteristics, Uses and Challenges Why BIs Survive a Validated Cycle

Subscribe now

Full of expert takes on industry trends and the latest technical education offerings. Spore News gives you the insight you need to prepare for what's next.

MesaLabs

Our Solutions

  1. Sterilization & Cleaning Monitoring
  2. Mail-In Spore Testing
  3. Continuous & Process Monitoring
  4. Environmental Controls & Air Quality
  5. Occupational Health & Safety
  6. Renal Care Quality Control
  7. Torque Testing

About us

  1. Our Purpose
  2. Mesa Brand Family
  3. Executive Team
  4. Careers
  5. Investor Information
  1. Sterilization & Cleaning Monitoring
  2. Mail-In Spore Testing
  3. Continuous & Process Monitoring
  4. Environmental Controls & Air Quality
  5. Occupational Health & Safety
  6. Renal Care Quality Control
  7. Torque Testing
  1. Our Purpose
  2. Mesa Brand Family
  3. Executive Team
  4. Careers
  5. Investor Information
  1. Contact Us

    Corporate Headquarters
    Mesa Laboratories, Inc.
    12100 West 6th Ave.
    Lakewood, CO 80228

    303.987.8000
    customerservice@mesalabs.com

Connect with us

Follow us on Facebook Follow us on LinkedIn Follow us on Twitter Follow us on Facebook
©2022 Mesa Labs, Inc. All rights reserved. |   Terms, Conditions & Privacy Policy   |  
Gyros Protein Technologies Agena Bioscience
©2022 Mesa Labs, Inc. All rights reserved. Terms, Conditions & Privacy Policy