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Updated: Oct 2, 2026

In Vitro Evaluation of the Potentiating Effects of Plant-Derived Molecules on Conventional Biocides
Published on: May 8, 2026
[Benzalkonium chloride: unacceptable to sterilize or disinfect medical or dental instruments]
E Acosta-Gío1, A Herrero-Farías, V H Mata-Portuguez
1Laboratorio de Microbiología y Control de Infecciones, División de Estudios de Posgrado e Investigación, Facultad de Odontología, Universidad Nacional Autónoma de México (UNAM), México, D.F. acostag@servidor.unam.mx
Objective:
To compare the sporicidal activity of benzalkonium chloride (BKC) with that of glutaraldehyde.
Material And Methods:
A comparative study was conducted at the microbiology laboratory of Facultad de Odontología, Universidad Nacional Autónoma de México. Bacillus subtilis ATCC 9372 spores were exposed to these germicides (1 spore x mL) on a 0.22 mm filter. After completing the contact time the spores were washed and the filters were incubated on nutrient agar for 72 h at 37 degrees C.
Results:
BKC did not eliminate B. subtilis spores at the concentration used, not even after increasing contact time to 15 h (900-fold the recommended time). Two percent glutaraldehyde destroyed spores only after 10 h of contact. Urea and sodium chloride showed no sporicidal activity.
Conclusions:
The results confirm that BKC lacks sporicidal activity and confirm that this quaternary ammonium compound is not able to "sterilize" or "disinfect" medical and dental instruments.
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