| General Causes | Testing the biocide against inappropriate microbes Insufficient contact times Incorrect preparation of the use-dilution
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| Inoculum | Poor viability of inoculum suspensions Incorrectly prepared fungal and bacterial spore suspensions Lethality after drying (e.g., Pseudomonas aeruginosa)
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| Surfaces | Porous or damaged surfaces Uneven inoculation or product coverage due to surface curvature or surface tension Incorrect procedure for cleaning and sterilizing coupons before use
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| Neutralization | |
| Recovery | |