Identification of contaminated juice microorganism by ۱۶s rRNA sequencing and decontamination by PEF

Background and Aim: Survival and growth of bacterial pathogens is one of the main concern in the juice industry. Thermal pasteurization is the most common method to eliminate spoilage microorganism in juices. However, some kind of bacteria are heat-resistance, survive after pasteurization and reduce the taste, color or odor of juices. Non-thermal pasteurization methods have been employed in fruit juices to overcome the negative effects of thermal pasteurization. Due to the observation of non-pathogenic and heat-resistant microbial contamination in some products of Iranian-made liquids, this project was designed to identify the type of contamination and provide a suitable solution for its control.Methods: The bacterial type was identified by analysis of ۱۶S rRNA gene, obtained by colony PCR amplifications. Two physical methods for eliminating pollution were considered: ۱) simple UV light treatment and ۲) pulsed electric field (PFE).Results: The bacteria was identified as Alicyclobacillus acidoterrestris. According to the results UV not only did not decrease the number of spores but also induce the sporulation. Furthermore, UV-generated ozone can reduce the antioxidant properties of the juice. In the next step, the Pulsed Electric Fields (PEF) method was tested. PEF technology has been extensively studied for the inactivation of various microorganisms. The results indicated that this FDA-approved method successfully reduced the bacterial counts.Conclusion: In conclusion, ۱۶s rRNA sequencing successfully identified the bacterial type. PEF method was verified as an effective method for elimination of this contamination.

Keywords:

Pasteurization , Food Irradiation , Fruit Juices , Alicyclobacillus acidoterrestris