NEUTRAL ELECTROLYSED WATER COMBINED WITH ULTRASOUND TREATMENT FOR SANITISING STAINLESS STEEL COUPONS

Abstract

Ultrasound coupled with low concentration neutral electrolysed water (free available chlorine: 4 mg/L), was proposed for sanitising stainless steel coupons. For planktonic cells, NEW could reduce survival population of Escherichia coli ATTC 25922 and Pichia pastoris GS115 for 5 min and 3 min. For air-dried attached microbial cells, no more than 1.2 log CFU/coupon was reduced by NEW. In the AFM study, both E. coli ATTC 25922 and P. pastoris GS115 showed visible cell damage after NEW treatment. When NEW was combined with ultrasound, the air-dried cells of the three strains on coupons were reduced below 2 log CFU/coupon. The increased protein leakage suggests the combined treatment could intensify microbial cells? membrane permeability. In the case of biofilms, NEW combined with ultrasound also significantly reduced the survival cells for all three strains. The results suggest that NEW combined with ultrasound is a promising approach to sanitise food equipment effectively.