The advantages and disadvantages of EO water

The main advantage of EO water is its safety. EO water which is also a strong acid, is different to hydrochloric acid or sulfuric acid in that it is not corrosive to skin, mucous membrane, or organic material. On the other hand, sodium hypochlorite was proved to have a strong toxicity, such as skin irritation, membrane irritation, acute toxicity, and so on (Mori et al., 1997; Sekiya, Ohmori, & Harii, 1997; Shigeto et al., 2000). Currently used hatchery sanitizers

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(formaldehyde gas and glutaraldehyde) are noxious to humans and chicks, and may pose a serious health risk (Russell, 2003). Furthermore, the use of formaldehyde gas and glutaraldehyde are gradually being limited because of the adverse effects this chemical has on the environment. Sakurai et al. (2003) also stated that EO water provides a useful means of cleaning and disinfecting digestive endo- scopes between patients. It is safe for the human body and for the environment. In addition, the cost of using EO water is much less expensive (5.3 yen/L) compared with glutaraldehyde (1200 yen/L) (Sakurai et al., 2003).

When EO water comes into contact with organic matter, or is diluted by tap water or reverse osmosis (RO) water, it becomes ordinary water again. Thus, it’s less adverse impact on the environment as well as users’ health. More- over, compared with other conventional disinfecting tech- niques, EO water reduces cleaning times, is easy to handle, has very few side effects, and is relative cheap (Tanaka et al., 1999). Chemicals used for cleaning and dis- infection are expensive and represent an operating expense for the dairy producer. Once the initial capital investment is made to purchase an EO water generator, the only oper- ating expenses are water, salts and electricity to run the unit (Walker et al., 2005b).

The main disadvantage of EO water is that the solution rapidly loses its antimicrobial activity if EO water is not continuously supplied with H+, HOCl and Cl2 by electrol- ysis (Kiura et al., 2002). EO water is gaining a reputation in various fields as a more capable disinfectant than conven- tional chemical disinfectants. However, problems, such as chlorine gas emission, metal corrosion, and synthetic resin degradation, due to its strong acidity and free chlorine con- tent have been a matter of concern. Although metal corro- sion and synthetic resin degradation occurred, they were not serious on hemodialysis equipment (Tanaka et al., 1999). Ayebah and Hung (2005) also indicated that EO water did not have any adverse effect on stainless steel, it can still be safely used as a sanitizer to inactivate bacteria on food contact surfaces made from stainless steel in food processing. After disinfection, washing food equipment with sterile water can completely avoid metal corrosion. During the EO water generation process, chlorine ions are generated, and thus chlorine gas is emit- ted. This necessitates the use of standard-type extractor fan.