Reduction of date microbial load with ozone

Davood Farajzadeh, Ali Qorbanpoor, Hasan Rafati, Mohsen Saberi Isfeedvajani


  • Background: Date is one of the foodstuff s that are produced in tropical areas and used worldwide. Conventionally, methyl bromide and phosphine are used for date disinfection. The toxic side effects of these usual disinfectants have led food scientists to consider safer agents such as ozone for disinfection, because food safety is a top priority. The present study was performed to investigate the possibility of replacing common conventional disinfectants with ozone for date disinfection and microbial load reduction.
  • Materials and Methods: In this experimental study, date samples were ozonized for 3 and 5 hours with 5 and 10 g/h concentrations and packed. Ozonized samples were divided into two groups and kept in an incubator which was maintained at 25°C and 40°C for 9 months. During this period, every 3 month, microbial load (bacteria, mould, and yeast) were examined in ozonized and non-ozonized samples.
  • Results: This study showed that ozonization with 5 g/h for 3 hours, 5 g/h for 5 hours, 10 g/h for 3 hours, and 10 g/h for 5 hours leads to about 25%, 25%, 53%, and 46% reduction in date mold and yeast load and about 6%, 9%, 76%, and 74.7% reduction in date bacterial load at baseline phase, respectively. Appropriate concentration and duration of ozonization for microbial load reduction were 10 g/h and 3 hours.
  • Conclusion: Date ozonization is an appropriate method for microbial load reduction and leads to an increase in the shelf life of dates.
  • Key words: Date, food safety, methyl bromide, microbial load, ozone

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