Effect of slightly acidic electrolyzed water against pathogenic microorganisms inoculated on chicken skin

Introduction: Slightly Acidic Electrolyzed Water (SAEW) has emerged as an environmentally friendly disinfectant in food safety. Its antimicrobial action, due to the presence of chlorinated compounds makes it suitable for reduction of pathogenic microorganisms in fresh meat.

Methods: SAEW was produced by the electrolysis of 5g NaCl/L using an AquaVolta® Water Tractor to obtain a solution of pH 6. Subsequently, different concentrations of active chlorine (5, 25, and 100 ppm) were prepared. Chicken skin pieces were inoculated with 5×10⁶ cfu/ml of a microbial cocktail (Cocktail A: Escherichia coli and Staphylococcus aureus; Cocktail B: Salmonella Typhimurium and Listeria monocytogenes) standardized by OD600 nm. After 15 minutes, the samples were immersed in 45 ml of SAEW for 5 minutes. Then, decimal dilutions were prepared and spread-plated onto selective agar plates for enumeration in days 0, 1, 3, 7 and 9. Drinking water was used as negative control and drinking water inoculated was used as positive control. Results were expressed as log cfu/g.

Results: Treatment of inoculated chicken skin with SAEW proved effective in reducing the pathogenic microorganisms. For Escherichia coli, an initial reduction in counts was observed, with absence of detection in day 7 (25 and 100 ppm) and day 9 (5 ppm). For S. aureus, 100 ppm was the most effective treatment, achieving a 2.06 log cfu/g reduction. SAEW at 100 ppm was the most effective treatment against Salmonella Typhimurium, eliminating it by day 9 with a 3.18 log cfu/g reduction. For L. monocytogenes, higher chlorine concentrations achieved reductions of up to 2 log cfu/g, despite no significant changes during storage (p > 0.05).

Conclusions: SAEW demonstrated effective antimicrobial activity on chicken skin, notably against E. coli and Salmonella Typhimurium, moderate efficacy on S. aureus, and limited effect on L. monocytogenes, highlighting its potential as a sustainable decontamination method.