Research Journal of Biotechnology Vol. 13 (4) April (2018) Res. J. Biotech 51 Acidic electrolyzed water, hydrogen peroxide, ozone water and sodium hypochlorite influence quality, shelf life and antimicrobial efficacy of cherry tomatoes Mohammad Zahirul Islam 1,2 , Mahmuda Akter Mele 1 , Khalid Abdallah Hussein 3 and Ho-Min Kang 1,2 * 1. Division of Horticulture and Systems Engineering, Program of Horticulture, Kangwon National University, Chuncheon 24341, KOREA 2. Agriculture and Life Science Research Institute, Kangwon National University, Chuncheon 24341, KOREA 3. Botany and Microbiology Department, Faculty of Science, Assiut University, 71516 Assiut, EGYPT *hominkang@kangwon.ac.kr Abstract To maintain the quality and shelf life of cherry tomatoes, microbial decontamination is essential. The objective of this study was to determine the effect of acidic electrolyzed water (AcEW), hydrogen peroxide (H2O2), ozone water (O3) and sodium hypochlorite (NaClO) on quality, shelf life and microbial decontamination of cherry tomatoes. Water was used as control. AcEW, H2O2, O3 and NaClO were sprayed one day prior to harvest. Afterwards, tomato fruits were stored at 5 ˚C to determine their quality, shelf life and microbial activity. Respiration (p ≤ 0.001) and ethylene production (p ≤ 0.01) were significantly lower in O3 -treated tomato fruits compared to those in other treatments. The lowest fresh weight loss and the longest shelf life 20 days (p ≤ 0.05) were found for O3 -treated tomato fruits. Their fungal incidence rate (p ≤ 0.001) and microbial activity were the lowest. However, fruits firmness 13.36N (p ≤ 0.01) was significantly retained for O3 -treated tomato fruits. Color development, lycopene content and fructose and glucose contents suppressed by O3 -treatment might have prolonged the shelf life of tomato fruits. Based on comprehensive results of physiological, physicochemical and microbiological analysis, O3 - treated tomato fruits prolonged shelf life and maintained their quality at 5˚C. Therefore, O3 - treatment might have great potential to be used for long time storage of cherry tomatoes. Keywords: Firmness, Fungal incidence, Sterilization, Vitamin C. Introduction Acidic electrolyzed water (AcEW), hydrogen peroxide (H2O2), ozone water (O3) and sodium hypochlorite (NaClO) have achieved massive acceptance as sterilizing agents to maintain fruits quality and storability while decreasing microbial activity over several decades. To reduce microbial contamination from fresh fruits and vegetables, single or combined methods with acidified sodium chloride, alkaline- based sanitizers, chlorine, chlorine dioxide, electrolyzed water, high pressure, hydrogen peroxide, mild heat, organic acid formulations, oscillating magnetic fields, ozonated water, peroxyacetic acid, pulsed electric field, ultrasound and ultraviolet radiation might be effective 1 . However, most of these methods are harmful to human health and the environment 2 . Therefore, safe antimicrobial agents are needed for fresh fruits, vegetables and organic foods for the food industry 3 . AcEW is a strong sterilizing agent in agriculture (fruits, vegetables, seafood, eggs, poultry, raw meat and carcasses). It has bactericidal, fungicidal and virucidal effects, thus maintaining the quality and the shelf life of agricultural products in pre- and post- harvest applications 4 . H2O2 works as a signaling molecule. It generates reactive oxygen species (ROS) in plants, thus increasing oxidative stress due to more ROS compared to metabolism 5 . The entire chemical generates free radical and transfers single electron for cavitations during the cooling phase. It is known that hydrogen atoms and hydroxyl radicals recombined with H2O2 have bactericidal properties 6 . O3 -treatment during fruits and vegetable preservation can increase antimicrobial and antioxidant activities as well as vitamin C and phenolic contents. However, its efficacy is influenced by production, application duration, application method, commodity, concentration, microbes and storage condition 7 . Although NaClO is the most widespread disinfection agent, it has limitation against pathogens. In addition, it generates carcinogenic compounds 8 . Moreover, hypochlorite-based systems are prohibited for fresh fruits and vegetables in many European countries due to high risk of cancer. Therefore, preservation technologies that are safe for consumers are increasingly needed 9 . Pre-harvest applications of sterilizing agents may be effective for fresh tomato fruits decontamination. In addition, they might minimize packing time. Research on sanitization method of fresh cherry tomato that is environment-friendly and effective in reducing microbial activity while increasing their quality and shelf life is limited. Therefore, the objective of this study was to determine the effect of acidic electrolyzed water, hydrogen peroxide, ozone water and sodium hypochlorite on quality, shelf life and microbial decontamination of cherry tomato fruits at storage temperature of 5˚C. Material and Methods Tomato samples preparation and storage: Cherry tomatoes (Solanum lycopersicum cv. “Unicorn”) were