Methods
The efficacy of MCDMH-Z for the odor control of 3M3MB was determined by solid-phase microextraction and gas chromatography mass spectrometry analysis, colorimetric analysis and a sensory panel. Enzyme inhibition was monitored by a colorimetric coupled assay for ammonia. The antimicrobial properties were measured by a reduction in colony-forming units (CFUs).
Results
3M3MB proved highly susceptible to modification by MCDMH-Z granules. Headspace above litter exposed to MCDMH-Z showed no detectable 3M3MB; levels >59 ng were detected in commercially available products. Urease activity decreased by >97% after incubation with MCDMH-Z to 0.14 mg/ml. Cat litter F showed comparable inhibition (0.13 mg/ml); others showed less inhibition, producing up to 4.8 mg/ml of ammonia. MCDMH-Z reduced the CFUs of Proteus vulgaris by six log reduction values in 30 mins; in the same amount of time, no reduction was seen with commercial products tested. The odor control capability of the MCDMH-Z granules was further supported by a sensory panel scoring 3M3MB-spiked litters. Conclusions and relevance: Samples of commercially available litter products showed an effect on malodor, or inhibition of urease, or contained antimicrobial activity; no samples were capable of accomplishing these concurrently. In contrast, MCDMH-Z granules were effective in all three test categories. Control of felinine-derived odors, in particular, has the potential to improve cat owner satisfaction, and may beneficially affect cat behaviors provoked by pheromonally active sulfurous metabolites deposited in the litter.