Industrial Use Biological Indicators
Standard Biological Indicators (BIs) are easy to use and are available for industrial or healthcare use. However, some manufacturing situations require a modified or specialty Biological Indicator to assist in validating the sterilization process. Manufacturers and validation specialists require unique tools where spore strips and ampoules are not suitable because of size, packaging or carrier material. Mesa offers a full line of Industrial Use BIs to address the unique requirements of the medical device and pharmaceutical industries.
Carriers
Discs have advantages over spore strips due to their size. Different materials may be compatible only with specific modes of sterilization. Discs can be used to monitor various sterilization methods and can be inoculated with any organism we manufacture. Several types and sizes of discs are available including: paper, borosilicate paper, and stainless steel. The user must determine the suitability of the indicator for their particular use.
| Steel Discs
Steel discs are representative of materials found in an isolator, and are compatible with vapor hydrogen peroxide. We strongly recommend our polished stainless steel to eliminate crevices in the carrier which can lead to tailing.
The oblong disc is inoculated with G. stearothermophilus1, catalog # 3A-6100ST for use in H202 vapor. Discs are packaged in a Tyvek/Tyvek® pouch and may be exposed in the pouch or an off-center hole in the disc allows them to be removed from their package and suspended throughout the isolator to insure proper flow. See Certificate of Analysis for resistance characteristics. Additional information on Peroxi-Disc
Paper discs have been used to validate sterilization of contact lenses in steam where placement of a strip was impossible due to its size. They are also suitable for EO, Dry Heat (up to 180°C) and radiation sterilization.
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| Woven Cotton Threads
Threads can be used to monitor various sterilization methods and can be inoculated with any organism we manufacture. Threads have been used at the interface of a syringe and plunger to show sterilant penetration and efficacy at that point. Other uses include placement in tubing and small vials.
Bio-threads are 100% cotton, 3/4" long, and can be inoculated with B. atrophaeus1, G. stearothermophilus1 or with another organism.
The device/lumen into which the thread is inserted affects its resistance characteristics.
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| Steel Wires
Wires can be inoculated with G. stearothermophilus spores and placed into very small lumens. Due to their rigid nature, they are easy to retrieve even if there is condensation within the lumen. Wires can also be made with a closed loop at one end, so a small wire can be attached to ease in retrieval.
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| ProSpore DH
ProSpore DH is a biological indicator (BI) specifically designed for Dry Heat sterilization and is uniquely suited for extremely high temperature processes. ProSpore DH won’t char or introduce particulates as a paper strip might. More info.
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| ProLine
Biological Indicator system designed for use in the validation or monitoring of steam or EO sterilization cycles of tubing ranging from 1/8" to 5/8" tubing ID. The ProLine PCD (Process Challenge Device) contains a filter paper disc inoculated with bacterial spores of Geobacillus stearothermophilus (steam) or Bacillus atrophaeus (EO). More info.
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| Steel Coupons
Steel Coupons (same size as our standard paper strip) are intended for use in dry heat ovens at depyrogenation temperatures.
Inoculated with 106 B. atrophaeus spores, they are used to correlate spore death (sterilization) with endotoxin reduction. Mesa does not sell endotoxin or other LAL reagents at this time.
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| Paper strips
Paper spores strips are available in our standard one and one-half inch length, half length, and 2mm x 10mm sizes and can be used in any sterilization method compatible with paper products. More info.
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| Steri-Chart
Steri-Chart is a set of strips with 5 different populations, all made from the same spore batch for use in cycle development. Expose the five test strips to determine what level of sterility is being delivered by a particular cycle (industrial use only).
A control strip is also included. Available with G. stearothermophilus (log 3, 4, 5, 6, & 7 test strips and a log 5 control) or B. atrophaeus (log 4, 5, 6, 7, & 8 test strips and a log 6 control).
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| Spore Suspensions
Are diluted aliquots from our primary spore crop (batch). They are used to directly inoculate (and therefore challenge) a material or solution with a known concentration of spores. US FDA requires pharmaceutical and medical device manufacturers to challenge their products directly with spores prior to approving them for sale. This challenge is intended to determine if the device's carrier material or pharmaceutical's properties (viscosity, salt content, etc.) has any sporicidal or preservative effect that will impact the manufacturer's ability to sterilize the product and to determine instructions on how the user can sterilize the device if reusable. More info.
Suspensions offered in a 40% ethanol solution or 100% deionized H2O.
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Species
Mesa manufactures many species of non-pathogenic spore-forming bacteria. Most are used for various types of sterilization, though some have other uses. Following is a brief description of the most common uses:
B. subtilis1 – Used to test the growth promotion ability of bacteriological media (specified in USP and other compendial monographs). We do not certify this organism with any resistance characteristics.
B. subtilis1 (called “ Designate 5230”) is used in steam sterilization procedures below 121C. Some pharmaceutical products are sterilized at 106° to 115°C for longer times because they are heat labile and would be damaged at 121°C or higher temperatures. This species has been used as a challenge to the lower temperatures in steam, where G. stearothermophilus would be too great a challenge. In using a lesser challenge (C. sporogenes species and environmental isolates are also used) it is necessary to have an extremely high level of control over the manufacturing process, environment, and bioburden of components. This organism is certified with a Steam D and z-value so its resistance at the lower temperatures can be determined.
G. stearothermophilus1 has been used for steam and other types of sterilization by several BI manufacturers. In particular, it has been used to validate Vapor Hydrogen Peroxide (VHP) sterilization of barrier isolators and clean areas in pharmaceutical production. To be able to provide a comparable product we also offer G. stearothermophilus1 and test it in H2O2 vapor. This product is typically inoculated onto steel carriers so it is compatible with the H2O2 process. This organism is certified with an H2O2 D-value.
G. stearothermophilus1 is used to detect residual antibiotics in dairy products. We do not certify this organism with any resistance characteristics.
B. thuringiensis1 – This species has a protein crystal on the spore coat that makes the spores toxic to various insect larvae. In Canada, some trees are sprayed with a spore suspension to protect them from certain larvae. Geneticists have engineered this protein to be expressed in some varieties of corn (referred to as Bt-corn). B. thuringiensis has also been used as a surrogate to B. anthracis or other more hazardous organisms in testing decontamination processes. We do not certify this organism with any resistance characteristics.
B. cereus and B. megaterium would be used in a similar manner to B. subtilis designate 5230 (lower temperature steam sterilization at 106° to 115°C). B. cereus is also used as a surrogate for B. anthracis and other more dangerous organisms in testing decontamination processes. We do not certify this organism with any resistance characteristics, but one can be provided upon request for a fee.
Packaging
Carriers can be packaged individually in glassine paper, a Tyvek® pouch, or in bulk plastic bags (no primary packaging). Carriers (individually wrapped) are sold in quantities of 100. Bulk packaged items are sold in quantities of 1,000. Steel Discs are only packaged individually in Tyvek® pouches.
Sterilization/Carrier compatibility:
Hydrogen peroxide (vapor or plasma) is not compatible with cellulosics (paper, wood pulp products), so Mesa’s spore strips and blue glassine packaging cannot be used with this type of sterilization. Tyvek packaging and steel carriers are recommended.
Depyrogenation temperatures (180° to 250°C) char or incinerate paper, so we recommend our steel strip carrier. This product is packaged in a Tyvek® pouch so the user can handle it without contaminating the lab with spores. Mesa does not offer a foil package for our steel strips, but recommends that the user wrap the strip in foil or place it inside a glass container prior to exposure in the depyrogenation tunnel/oven. This will assist aseptic transfer to media after the exposure.
Procedure for use (general)
Spore carrier may be removed or left in primary packaging. Place carrier into test environment. Within 4 hours (per USP) of completion of the sterilization cycle, aseptically transfer the spore carrier from the test unit into sterile Trypticase Soy Broth. An acid indicator may be used to facilitate detection of growth. Incubate at 55-60°C for G. stearothermophilus, 30-35°C for B. atrophaeus, for seven days. Check daily for growth and record growth as a failed sterilization cycle.
Certification
Mesa certifies the species and population of each lot. Some carriers may have D-value determined on the carrier in a particular packaging. Call for specific availability of resistance information. We can also provide resistance characteristics of the spores from the same batch on a paper strip packaged in glassine envelopes (Steam, Dry Heat, and EO) as a reference. Since the carrier will likely be removed from its package and placed inside a lumen or other environment, which may increase/decrease the resistance. The user must determine the suitability of the unit for their particular use. Actual D-value is dependent upon placement of the carrier and the accessibility of sterilant to that placement.
Storage
Store away from sterilants, out of direct sunlight, and in cool dry place (15°C-27°C, 30-70%RH).
Samples
Mesa is happy to provide samples so the user can determine the indicator’s suitability for their particular use.
Lab Services
Mesa performs Steam, EO and Dry Heat resistance studies, organism ID, and population verification on our BIs, your coupon or competitor's products. Contact Mesa for specific details.
Steam, Dry Heat, and EO D-value testing according to USP recommended procedures in our AAMI compliant BIER vessels. Raven can inoculate a coupon, inoculate and fill 1 to 20ml ampoules with your product, or verify a competitor's claim for population and D-value/z-value. Testing performed includes:
- Steam D-value on a commercially prepared BI
- EO D-value on a commercially prepared BI
- Population analysis of a commercially prepared BI
- Inoculation of client provided coupon with 106 G. stearothermophilus or B. atrophaeus
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- Custom filled ampoules
- Culturing of Biological Indicators
- Custom BI development
- Organism Identification (Biolog)
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Related Information
Note:
1 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.