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Product Inoculations

The product-inoculation service provides inoculated samples or carriers with specific test organisms that are used to test the ability to sterilize a device to a given sterilization cycle. This study is useful for research and development (R&D) and process development of different methods of sterilization, including ethylene oxide (EO), steam, dry heat, vaporized hydrogen peroxide, and other methods. Inoculations can be performed with various biological indicators (BI) configurations such as commercially prepared spore suspensions, paper strips, discs, wires, and sutures. Inoculation sites generally contain at least one million spores (106). Other populations can be achieved upon request. The products can be used for R&D cycles, comparative-resistance cycles (to determine the most resistant product location), or product D-value studies.

Note: To purchase BIs for your inoculation project, please complete a supply order form and submit it to eosupplies@nelsonlabs.com along with a copy of your PO. We recommend that BI orders be placed in advance in case Nelson Labs does not have the supply on hand.

Applicable Standards

  • ANSI/AAMI/ISO 11135
  • ISO 17665

Testing Locations

Study Outline

The product-inoculation study involves placing spores of the appropriate BI organism in various locations on the device, including those judged most difficult to sterilize. Inoculating the actual product in its most resistant location is the only definitive way to determine the resistance to sterilization. All types of products or components can be inoculated and then exposed to sterilization to determine the ability to sterilize the device. Different test organisms and different populations can also be used if requested.

All sterilization standards using the overkill method require the manufacturer to demonstrate inactivation of the target organism when inoculated in the most difficult-to-sterilize location with the appropriate indicator organism. For EO and dry heat, the correct organism is Bacillus atrophaeus, and for steam and vaporized hydrogen peroxide, the indicator organism is Geobacillus stearothermophilus.

Nelson Labs has extensive experience in product inoculation and can use your samples for further sterilization testing at the lab, or we can ship them back to the client or directly to the contract sterilizer for validation studies.

To submit product for inoculation, please include the following in your shipment:

  • Protocol and/or diagram of BI placement
  • Additional materials (e.g., BIs, packaging)
  • Completed Sample Submission Form
  • Purchase order

Note: If you are purchasing BIs from Nelson Labs, please complete a supply order form and submit it to eosupplies@nelsonlabs.com along with your PO. Advance purchase is recommended to avoid delays in scheduling your product inoculation. For guidance on completing the supply order form, you may download our reference sheet.

If you have additional questions about product inoculation test services or would like to consult with an expert at Nelson Labs, just send us a request or call us at +1 (801) 290-7500.