Ozone application to extend shelf life of vegetables by microbial growth inhibition

¹ Diponegoro University, Center for Plasma Research, Faculty of Science and Mathematics, Semarang, Indonesia
² Diponegoro University, Physics Department, Faculty of Science and Mathematics, Semarang, Indonesia

^* Corresponding author: adeika.susan@st.fisika.undip.ac.id

Abstract

Ozone has been used to extend the shelf life of vegetables by inhibiting the decomposing microbial growth. The study was conducted using six types of vegetables; i.e. broccoli, tomato, mustard, celery, leek, and lettuce; treated and stored using ozonation techniques. The six types of vegetables were divided into two treatment groups, i.e. ozone-washed and not washed, and stored in ozone-filled cold storage at a dose of 15 gr/m³ per day. Total microbial testing was performed to determine the number of microbes in each vegetable sample. In addition, proximate testing was performed to observe the decreasing rate in nutrient content during storage time. The results showed that ozone-washed tomatoes is the most durable varieties which can stay fresh until day-12 with TPC and YMC values of 4.8x10⁵ CFU/g and 13x10⁵ CFU/g respectively. While the control tomato has a TPC and YMC value of 2.0x10⁶ CFU/g and 85x10⁶ CFU/g respectively. In addition, the proximate test results showed that the nutrient content in each ozone-washed samples didn't decrease significantly compared with the control samples. These results indicate that ozone-washing treatment can extend the shelf life of vegetables while still maintaining their nutritional value.