RESUSCITATION OF VIABLE BUT NON-CULTURABLE (VBNC) STAPHYLOCOCCUS AUREUS AS A RESULT OF ELECTROLYZED WATER (EW) ON FOOD CONTACT SURFACE

Khalid Tolba*, Huda Elsayed*, Al-Shaimaa T. Hanafy, Sarah Abbas and Nesreen Eleiwa

ABSTRACT

The use of electrolytically generated acidic water (SAcEW) as a standalone sanitizer for food contact surfaces, or in sequence with electrolytically generated alkaline water (SAlEW) as a potent cleaning agent due to its sodium and potassium hydroxide content, effectively eliminated Staphylococcus aureus contamination and demonstrates promise as a broad-spectrum, high-performance bactericide in the food production industry. This study investigated the disinfection efficacy of SAlEW, SAcEW, and their combined application against S. aureus, including quantification of dead cells and Viable but Non-Culturable (VBNC) cells post-resuscitation. SAcEW treatment significantly reduced S. aureus populations by 4–6 log CFU/g and achieved a 100% reduction on stainless steel and plastic surfaces. Sequential treatments with SAlEW followed by SAcEW resulted in a 100% reduction across all three tested surfaces (stainless steel, glass, and plastic), whereas SAlEW alone eliminated a portion, but not all, of the S. aureus population. Post-resuscitation analysis revealed the following percentages of VBNC and dead cells, respectively: SAlEW—40.65% and 22.58% (SS), 38.95% and 22.42% (glass), 34.68% and 29.5% (Plastic); SAcEW—9.68% and 74.19% (SS), 24.22% and 46.16% (Glass), 21.1% and 78.9% (Plastic); and the combined SAlEW/SAcEW treatment—0.0% and 100%, 19.64% and 80.36%, and 0.0% and 100%, respectively. The public health implications of the VBNC state of S. aureus are discussed.

Keywords: Viable but Non-Culturable Staph. aureus (VBNC), Electrolyzed water (SAlEW & SAcEW), Resuscitation, RT-PCR, Propidium iodide (PI).