The following is an excerpt from a recent study published by Oxford Academic titled - “Red cabbage washing with acidic electrolysed water: effects on microbial quality and physicochemical properties”. Published 10 November 2018.

Study Background

Fresh-cut produce markets have increased steadily over the last 20 years worldwide, mainly because fresh-cut produces containing higher nutrients, greater taste, and being easier to prepare. Red cabbage is one of the world’s most widely consumed fresh-cut vegetables with high nutritional values relating to the antioxidants and anti-inflammatory activity of anthocyanins, vitamins, and minerals.

However, frequent incidence of food disease outbreaks associated with the consumption of fresh-cut vegetables and fruits have also been a major concern. Therefore, using effective decontamination processes to remove bacterial contaminants in fresh-cut red cabbage is essential to ensure its safe consumption.

The Risks of poor treatment

Moreover, it is well known that anthocyanins are very unstable and easily degradable since they are sensitive to factors like oxygen, temperature, pH, light, etc. Therefore, it is important to select proper treatment that are not only effective to inactivate pathogenic bacteria but also minimize the loss of nutrients and antioxidant activity of red cabbage.

Poor cleaning and sanitizing processes may increase the risk of foodborne outbreaks leading to public health concerns. In addition, economic losses may occur to the food industry due to product recalls, legal, and customer claims.

Under these pressures, the fresh-cut produce industries are seeking for effectiveness, environmentally friendly, and economical sanitation processes. Electrolysed water (EW) as ‘green’ process and technology is a relatively novel disinfecting solution that has been shown to effectively reduce pathogenic bacteria on fresh produces without any chemical residues.

Acidic Electrolysed Water

The acidic electrolysed water (AEW) contains hypochlorous acid, a weak acid. It has strong oxidation potential, and a shortage of electrons giving it the ability to oxidize and destroy microbes as well as toxins. Therefore, AEW can be used as a disinfectant and an antimicrobial agent.

It is well known that the treatments with AEW have many advantages in the decontamination of vegetables and fruits including without impact on the tissue pH, surface colour, general appearance, customer acceptance, and no off-odour or off-flavour production.  

In recent years, AEW as ‘green’ process and technology has gained interest as a bactericide against a variety of microorganisms, to remove pesticide residues, and to reduce mycotoxin attributes on the applications of agriculture harvest, supermarket, and food industry.

Results of Study

In the present study, the effects of ACC of AEW and treatment time on the inactivation efficacy of native microflora and artificially inoculated S. typhimurium DT104 on the red cabbage and in the processed washing water were evaluated.

The distilled water control (DW) treatments did not show statistically significant effects on the inactivation of all microbial cells compared with the untreated samples. In contrast, after the red cabbages were treated by AEW, the populations of native aerobic bacteria, and molds and yeasts, on the surfaces of red cabbage were significantly reduced 2.33–6.72 log CFU/g, and 0.94–3.48 log CFU/g, respectively. The most suitable ACC of AEW for washing red cabbage was 100 mg/L for 3 min. In these optimal process conditions, most of the native microflora were inactivated, and artificially inoculated S. typhimurium DT104 on the red cabbage were reduced by 40.2 per cent (3.67 log CFU/g), also the washing water has not been cross-contaminated, and could be recycled. The surface colour, pH, and total phenolic contents of red cabbage were not significantly affected by 3 min washing with the 100 mg/L of AEW. Although the anthocyanin contents and antioxidant activities of red cabbage were significantly reduced by 18.5 per cent for cyanidin, and 22.1 per cent for pelargonidin, and 11.2 per cent for DPPH radical scavenging activity, the impacts on the nutritional benefits of red cabbage were considered as limited and acceptable.

Therefore, 100 mg/L of AEW washing solution can be used as an alternative environmentally friendly sanitizer in fresh-cut food industry to prolong red cabbage shelf life. The results generated from the present study could provide useful information to the fresh produces and the fresh-cut produce industry to optimize processing conditions using AEW.

To read the full study, please follow this link