The effects of low-concentration electrolysed water (LcEW) (4 mg/L free available chlorine) combined with mild heat on the safety and quality of fresh organic broccoli (Brassica oleracea) were evaluated. Treatment with LcEW combined with mild heat (50 C) achieved the highest reduction in naturally occurring microorganisms and pathogens, including inoculated Escherichia coli O157:H7 and Listeria monocytogenes (P < 0.05). In terms of the antioxidant content of the treated broccoli, the total phenolic levels and ferric reducing antioxidant power remained unchanged however, the oxygen radical absorbance capacity of the treated broccoli was higher than that of the untreated control. In addition, mild heat treatment resulted in an increase in firmness. The increased firmness was attributed to changes in the pectin structure, including the assembly and dynamics of pectin. The results revealed that mild heat induced an antiparallel orientation and spontaneous aggregation of the pectin chains. This study demonstrated that LcEW combined with mild heat treatment was effective to reduce microbial counts on fresh organic broccoli without compromising the product quality.
39″ target=”_blank” rel=”noopener”>ABSTRACT – Full Text PDFThe effect of acidic electrolyzed water (AEW) on inactivating Escherichia coli O104:H4, Listeria monocytogenes, Aeromonas hyrol possible unhygienic practices during production and processing of shellfish without apparent changes in the quality of the shellfish.
The sanitising effect of low concentration neutralised electrolysed water (LCNEW, pH: 7.0, free available chlorine (FAC): 4 mg/L) combined with ultrasound (37 kHz, 80 W) on food contact surface was evaluated. Stainless steel coupon was chosen as attachment surface for Escherichia coli ATCC 25922, Pichia pastoris GS115 and Aureobasidium pullulans 2012, representing bacteria, yeast and mold, respectively. The results showed that although LCNEW itself could effectively reduce survival population of E. coli ATCC 25922, P. pastoris GS115 and low concentration A. pullulans 2012 in planktonic status, LCNEW combined with ultrasound showed more sanitising efficacy for air-dried cells on coupons, with swift ificantly reduced the survival cells both on coupons and in suspension for all three strains. The results suggest that LCNEW combined with ultrasound is a promising approach to sanitise food equipment.
Electrolysed oxidising water (E.O. water) is produced by electrolysis of sodium chloride to yield primarily chlorine based oxidising products. At neutral pH this results in hypochlorous acid in the un-protonated form which has the greatest oxidising potential and ability to penetrate microbial cell walls to disrupt the cell membranes. E.O. water has been shown to be an effective method to reduce microbial contamination on food processing surfaces. The efficacy of E.O. water against pathogenic bacteria such as Listeria monocytogenes, Escherichia coli and Vibrio parahaemolyticus has also been extensively confirmed in growth studies of bacteria in culture where the sanitising agent can have direct contact with the bacteria. However it can only lower, but not eliminate, bacteria on processed seafoods. More research is required to understand and optimise the impacts of E.O. pre-treatment sanitation processes on subsequent microbial growth, shelf life, sensory and safety outcomes for packaged seafood products.