# Simultaneous Study of the Combined Effect of Gliding Arc Plasma and Zataria multiflora Essential Oil on Pathogens Inactivation and Quality Changes in Sliced Iranian White Cheese

## TL;DR

This study explores combining plasma treatment and essential oil to reduce pathogens and preserve sliced Iranian white cheese.

## Contribution

The novel contribution is demonstrating that combining gliding arc plasma with Zataria multiflora essential oil effectively inhibits pathogens in cheese.

## Key findings

- Combining 2 min of GAP and 100 ppm ZEO most effectively inhibited E. coli and L. monocytogenes.
- 5 min of GAP combined with ZEO showed the highest inhibition of Aspergillus flavus.
- Cheese treated with 2 min of GAP and 100 ppm ZEO had the highest sensory acceptance.

## Abstract

This study aimed to inactivate
Escherichia coli O

111
,
Listeria monocytogenes
, and Aspergillus flavus on sliced Iranian white cheese by using the combination of gliding arc nonthermal plasma (GAP) and Zataria multiflora essential oil (ZEO). The cheese samples were exposed to different levels of GAP (0, 2, and 5 min) and ZEO (0 and 100 ppm) and stored at 4°C for 60 days. The extraction yield of ZEO based on dry weight was 1.66%. Carvacrol (33.85%) was the most important compound in ZEO. During the storage period,
E. coli
and
L. monocytogenes
counts increased in all samples. However, the most effective inhibition of
E. coli
and
L. monocytogenes
was observed in samples treated with 100 ppm ZEO combined with 2 min of GAP, and 100 ppm ZEO combined with 5 min of GAP, respectively, resulting in increases of only 1.35 and 1.8 log CFU/g over the storage period. In terms of the growth inhibition percentage of
A. flavus
, the lowest inhibition was detected in the presence of essential oil alone, while the highest inhibitory effect resulted from 5 min of plasma treatment combined with essential oil. GAP treatment also reduced the pH value of the cheese while increasing thiobarbituric acid reactive substances (TBARS). The control sample showed the lowest pH and the highest TBARS during storage. The highest overall acceptance sensory properties score was observed in cheese samples treated with 2 min of GAP and 100 ppm ZEO. According to the results of microbial, chemical, and sensory tests, Iranian white cheese samples treated with 2 min of GAP and 100 ppm ZEO can be used as a novel technique for sterilization and extending the shelf life of white cheese.

This study aimed to inactivate two pathogens on Iranian white cheese by using the combination of gliding arc nonthermal plasma (GAP) and Zataria multiflora essential oil (ZEO). The cheese samples were exposed to different levels of GAP and ZEO, and samples were stored. According to the results, Iranian white cheese samples treated with 2 min of GAP and 100 ppm ZEO can be used as a novel technique for sterilization and extension of the shelf life of white cheese.