Journal of Food: Microbiologia, Segurança e Higiene
Acesso livre

Abstrato

Ultrasound Treatment Effects on Staphylococcus aureus Cell

Akila A, Nadir A, Nouara OK, Amine B, Kamelia K, Khodir M

The aim of this study was to obtain valuable information about the effect of ultrasonic irradiation with a frequency of 20 kHz while discontinuing pulsation (10 s off, 5 s on) on the inactivation capability of Staphylococcus aureus ATCC 25923, in physiologic water samples.

Ultrasonic irradiation of bacterial samples with different populations of 10⁸, 10¹⁰ and 10¹² colony-forming units/mL by varying the volumes of the bacterial suspension (15 mL, 30 mL and 45 mL) was performed at a constant frequency with different amplitude levels 60%, 80% and 100%, various treatment times and temperatures 20, 30 and 50°C ± 2°C. The linear section of a plot showing a survival ratio logarithm vs. sonication time was used to determine the rate constant for ultrasonic inactivation. In spite of the fact that ultrasonic therapy resulted in a large mortality rate at 80% and 100%, contrary to predictions, a rise in S. aureus populations was seen at 60%.

The findings of this study suggest that ultrasound irradiation is a suitable method for the elimination of the main pathogen, such as S. aureus, at high amplitude 80% at temperatures that reach 50°C, given the widespread use of ultrasound for the sterilization of tools and equipment used in hospitals.