Evaluation of bacterial multiplication in cleaning cloths containing different quantities of organic matter

Abstract

Introduction: To determine a proper length of time for cleaning cloth usage, the present work aimed to evaluate bacterial multiplication in artificially contaminated cleaning cloths containing different amounts of organic matter.

Methodology: Cloths containing 1%, 5%, and 10% of bovine albumin were contaminated with Salmonella enteritidis 3091/05, Escherichia coli ATCC 25972, Staphylococcus aureus ATCC 25923, and Shigella sonnei CC07. They were incubated for different time periods at 30°C. Microbial multiplication was evaluated by bacterial counts and the ATP bioluminescence increase was monitored at sampling points. An ampicillin-resistant recombinant HSα E. coli strain was used as a pathogen surrogate to investigate the potential of microbial cloth dispersion.

Results: None of the strains showed expressive growth up to two hours of incubation. At three hours, the microorganisms demonstrated a slight increase, with E. coli ATCC 25972 showing a significant increase in cells (p < 0.05).  The ATP bioluminescence did not increase during the incubation period and confirmed the microbial count results, demonstrating that the amounts of organic matter tested did not interfere with bacterial multiplication during the first three to four hours of incubation. The dispersion experiment indicated that a cleaning cloth contaminated with 10⁴ CFU/cm² was able to spread 10² CFU/cm² of recombinant E. coli onto a stainless steel surface.

Conclusion: Based on these results, we suggest that an appropriate period of time for using disinfected cleaning cloths is around two hours, not exceeding three hours of usage.