Effect of Ozone Treatment on Shelf-life of Refrigerated Potato Strips

Abstract

Surface pasteurization with hot water is an effective method used for refrigerated fruits and vegetables to destroy microorganisms and sometimes improve quality. However, microbial recontamination and resulting growth will occur unless a near-aseptic environment is provided during packaging. Therefore, hot water treatment alone is not an option to extend shelf-life of refrigerated potato strips. Ozone is a strong antimicrobial agent which has been used to treat food. In this study, ozone gas was used, as an alternative to near-aseptic packaging, to extend shelf-life of refrigerated potato strips based on microbiological quality. Potato strips were blanched in 0.5% CaCl2 solution at 60°C for 10 min to improve texture by activating pectin methyl-esterase, blanched in boiling water for 5 min to further reduce microbial load and improve color by inactivating polyphenol oxidase, and then packaged into polyethylene bags. Ozone gas (5% wt/wt) was injected into the bag. Strips were treated as batch ozone for 20 s and continuous ozone for 5, 15 and 30 min. Treated strips were stored at 7°C for 28 days. Microbial growth was observed the following day for bags with no ozone treatments. Continuous ozone treatment was effective in extending shelf-life of refrigerated potato strips compared to batch ozone treatment. No spoilage was observed even after 28 days for 30 min continuous ozone treated strips. Fifteen minute continuous ozone treatment provided 21 days shelf life without microbial growth. Since potato strips were blanched, ozone treatment did not affect the quality; color. No difference was observed between the color of blanched strips and ozone treated blanched strips.