Reduction of microbial population of fresh vegetables (carrot, white radish) and dried fruits (dried fig, dried peach) using atmospheric cold plasma and its effect on physicochemical properties

Abstract

Non-observance of hygiene principles during storage causes excessive growth of microorganisms in these products and the return of export products to the manufacturer. The purpose of this research is to examine the antimicrobial effects of the jet cold plasma device and its impact on the physicochemical and sensory characteristics of a carrot, white radish, dried fig, and dried peach. For this purpose, the samples were inoculated with Escherichia coli O157:H7, Enterococcus faecalis, and Aspergillus niger. Then samples were treated with atmospheric cold plasma in the form of a jet probe and DC pulse source with 17 KV and 2.26A for 0, 3, 6, 9, and 12 min. The results showed that the rate of inactivation of microorganisms increases with increasing exposure time to atmospheric cold plasma. The maximum reduction of the microbial load was observed at 17 kV and 12 min. The resistance of microorganisms in dried fig and dried peach was higher than in carrot and white radish due to lower humidity. Also, A. niger showed the highest resistance to cold plasma compared with E. coli O157:H7, and E. faecalis. By comparing the average indices of a, and b, no significant change was observed between the treated and the control samples (p > 0.05). The texture structure remained intact after plasma application, and the plasma had no destructive effect on the texture. The samples treated with cold plasma did not show a significant effect on the physicochemical and sensory characteristics of different food products. Therefore, atmospheric cold plasma technology can be used as an efficient maintenance technique to enhance the shelf life of food products.

Keywords

• Aspergillus
• Cold plasma
• Dried fruits
• Enterococcus
• Fresh vegetables
• Inactivation