# Non-Thermal Methods for Ensuring the Microbiological Quality and Safety of Seafood
## 6 Electrolyzed Water--EW
### Microbiological Quality and Safety  
EW application offers great antimicrobial effect and can be used in association or not with other methods [197, 216] and antimicrobial agents such as bacteriocins [217] to achieve high microbial reduction numbers and extend the shelf life of fish and seafood products. Linked with those mentioned above, American shad (_Alosa sapidissima_) can be stored at 4 \({}^{\circ}\)C for 25 days, coated with chitosan (CH) solution (2% \(w\)/\(v\); pH 3.7) after washing with EOW (pH 2.4; ORP = 1185 mV; free chlorin, 70-80 ppm). The results revealed that EOW+CH was more effective than either treatment alone [218] ([PERSON] et al., 2014). During refrigeration, the total microbial population of untreated samples surpassed the 7-log CFU/g on day 10. At the same time, EOW, CH, or EOW+CH-treated samples did not reach this value until day 15 or 20, respectively. The lower numbers of TVC bacteria reported may be due to the formation of hypochlorous acid (HOCI) and the low pH of the EW leading to the cells' outer membrane damage [219] and the ability of CH to disrupt the lipopolysaccharide vascularizer of the outer membrane of Gram-negative microorganisms [220]. These findings can also be used to serve as comparisons with other studies showing that after treatment of fish with EW, the total microbial counts reduced and extended the shelf life [221, 222, 223, 224]. EW is also known for its efficacy against foodborne pathogens commonly found on seafood or seafood processing surfaces [207, 208, 209, 210]. Regarding this, [PERSON] et al. (2016) [202] investigated the effect of strong (SAEW) and weak (WEAW) electrolyzed water on _E. coli_ O104:H4, _L. monocytogenes, A. hydrophilia, V. parahaemolyticus_, and _Campylobacter jejuni_ inoculated on the surface of live clam (_Venerupis philippinarum_) and mussel (_M. edulis_). This study revealed the potential to use EW with strong ORP and chlorine concentration of 10-20 mg/L to inhibit the activity of pathogenic bacteria from important aquaculture shellfish, which are known to be contaminated or even accumulate these microorganisms by filtering the environmental water [225, 226]. EW studies on _E. coli_ O157:H7 and \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Types of EW** & **pH** & **ORP (mV)** & **ACC (mg/L)** & **Dilute Solution** & **References** \\ \hline AEW & 2.22 & 1137 & Approx. 41 & NaCl 0.1\% & [195] \\ AEWice 1 & 2.30 & \textgreater{}1100 & 38 & KCl 0.1\% & [196] \\ AEWice 2 & 2.64 & 1124 & 26 & NaCl 0.1\% & [197] \\ AEW 2 & 11.40 & \textgreater{}795 & NT & NaCl 12.0\% & [198] \\ NEW & 6.80 & 786 & 60 & NT & [199] \\ SAEW & 6.37 & 980 & 30 & NaCl 0.5\% and HCl 0.05\% & [200] \\ SAEWice 1 & 6.48 & 882 & 25 & NaCl 0.2\% and HCl 0.04\% & [201] \\ WAEW 1 & 3.55 & 950 & 10 & NaCl 40 mg/L & [202] \\ ECAS4 3 & 7.00 & 850 & 300 & NaCl 0.4-0.5\% & [203] \\ \hline \hline \end{tabular}  
* NT—variable was not included; 1 after generation, the EW is poured to freeze at –18 to –20 \({}^{\circ}\)C; 2 AIEW means alkaline EW; 3 WAEW means weak or weakly AEW.  
\end{table} 
Table 4: Types and physicochemical properties of electrolyzed water EW used on fish and seafood products. _L. monocytogenes_ inoculated on raw salmon fillets also showed comparable results as the shellfish findings from this study, with [PERSON] and [PERSON] (2006) [198] reporting reductions ranging from 0.47 to 1.07 log CFU/g and 0.40 to 1.12 log CFU/g, respectively. The maximum decrease was with acidic EW at 35 \({}^{\circ}\)C, pH 2.6, ORP 1150 mV, and 90 ppm free chlorine. [PERSON] et al. (2018) [199] investigated the effect of different electrolyzed water solutions (AEW and NEW) in combination with mild thermal treatment at 50, 55, 60, or 65 \({}^{\circ}\)C for 2, 6, or 10 min to reduce _L. monocytogenes_ on Atlantic salmon (_S. salar_). They observed that the NEW application for 10 min at 65 \({}^{\circ}\)C reduced the counts of _L. monocytogenes_ by 5.60 log CFU/g. These results comply with other authors also presented a high reduction in _L.