Mesa Labs offers a complete line of spore strips for sterility testing in various sterilization environments for both Healthcare and Industrial applications.

Mesa’s products are manufactured in accordance with USP and ISO Guidelines and the US Food & Drug Administration’s Quality System Regulations. Available in 100 count clear resealable bags.

Spore strips are in Schleicher & Schuell filter paper (#470) – size 6.4mm x 38.1mm – packaged in a peel open glassine paper pouch. Glassine paper is permeable to sterilant but resistant to moisture and air at ambient temperature/pressure. This allows the user to transport the strip within the glassine from the sterilizer to a laminar flow hood, where it can be transferred into recovery medium. Populations of strips are typically from 1.0 X 10n to 4.0 X 10n. Lot number and expiration date are printed on each glassine.

  • Geobacillus stearothermophilus* – For use in steam sterilization at 121.1°C (250° F) to 135°C (275° F), and Chemiclave®. After exposure to sterilant, incubate strips at 55-60°C.
  • Bacillus atrophaeus* – For use in Ethylene Oxide (600 mg/L) and Dry Heat Sterilization (D-value calculated at 160°C). After exposure to sterilant, incubate strips at 30-35°C.
  • Combined Species Spore Strips – G. stearothermophilus* (105) and B. atrophaeus* (106) on each strip. For use in Steam, EO, Dry Heat or Chemiclave® sterilizers.

* Derived from recognized reference strains as specified within USP, ISO or EN guidelines. These products are not certified as being representative of the reference strain and they should therefore not be used where a reference culture is specified.

24-Hour Incubation Claim

The Biological Spore Strips with Modified Tryptic Soy Broth with Bromocresol Purple (single species G. stearothermophilus ATCC #7953 or dual species G. stearothermophilus ATCC #7953 and B. atrophaeus ATCC #9372) are intended for use in testing the efficacy of steam sterilization cycles at 121°C-135°C. A reduced incubation time of 24 hours at 60°C +/- 2°C has been validated for steam sterilization when the Bacterial Spore Strip manufactured at Mesa’s Manufacturing Facility (either the single species G. stearothermophilus spore strip or the dual species spore strip) is used in conjunction with the Modified Tryptic Soy Broth with Bromocresol Purple also manufactured at Mesa’s facility.


Mail-In Service

Weekly biological monitoring (i.e., spore testing) is the standard of practice across the country for dental practitioners.

Mesa Labs is an industry leader in providing sterilizer monitoring solutions including mail-in and in-office spore testing, chemical indicators and record keeping. Learn more about achieving compliance with CDC, ADA and AAMI guidelines by clicking here.

Technical Specifications
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Technical Specifications

Mesa’s spore strips are certified for Species, Population, D-value, z-value (where appropriate) and Expiry.

Spore Strips Biological Indicator


24 Hours


  • Spore Strip for EO/Dry Heat: 24 months from date of manufacture
  • Spore Strip for Steam/Chemiclave® and Combined Species: 18 months from date of manufacture

EZTest® Steam / Flash

G. stearothermophilus

Species B. atrophaeus G. stearothermophilus G. stearothermophilus
Catalog# 1-6100 3-5100 3-6100
Units 100 100 100
Minimum Population








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