Cold plasma is implemented in the food industry for protecting the agricultural product from foodborne pathogens. In this case, dielectric barrier discharge cold plasma pen (DBD-CP) was applied to study its efficiency in inactivation of bacterial on oyster mushroom. The surface of the fresh oyster mushroom was treated with 5 kV of AC voltage with variable of treatment times (0-4 min). Data showed sufficient energy by DBD-CPP has inactivated the existence of bacterial on the oyster mushroom surface with undetectable of bacteria colony. The reactive species generated by cold plasma undoubtedly irreversibly damage the deoxyribonucleic acid, ribonucleic acid, and enzymes of gram bacterial, which eventually causes cell death. Above all, an understanding of the microorganism cell structure, the food surface types, and roughness is an essential in manipulating cold plasma processing parameters to achieve the maximum rate of microbial inactivation.
TopIntroduction
As the awareness of food safety and quality increases among consumers, demand for fresher, safer, and higher quality foods is increasing (Ji et al., 2018). High production and consumption of fresh crops, “ready to eat” such as vegetables and fruits, have resulted in the rise of agricultural associated foodborne outbreaks worldwide (Castro-Ibáñez et al., 2017). A wide range of fresh fruits and vegetables were implicated with foodborne diseases (FBD) due to the consumption of raw and minimally processed foods that do not meet the food safety and hygiene standard practices in a food supply chain (Shah et al., 2019). FBD caused either by infectious agents or their toxins that enter the body through the ingestion of food (Bayliss, 2012; Bastien et al., 2019). Viruses causing FBD attack cells of the digestive tract and propagate inside them subsequently they attack other cells of the digestive tract or enter other organs such as the liver or central nervous system and cause disease (Vasickova et al., 2005; O’Shea et al., 2019).
Several techniques were introduced to inactivate microorganisms during postharvest processing which includes the use of aqueous chemical sanitizers such as chlorine (Gabriel et al., 2016; Ramos et al., 2020) and organic acids (Sabillón et al., 2020), gaseous sanitizers (Rodríguez et al., 2017), non-thermal processing techniques such as high hydrostatic pressure, ozone and gamma irradiation, nanotechnology and electro-spraying of water (Atungulu et al., 2012; Neetoo & Chen, 2014). However, the use of these techniques have resulted in lower consumer acceptance, reduction in the nutritional values, affected the quality attributes of foods, increase the acid concentration and their reaction with organic matter can produce various toxic disinfection by-products (Ramos et al., 2020; Giaouris et al., 2018). Some postharvest handling techniques are not safe for consumers and environment, for example, quarantine crops in Japan are fumigated with methyl bromide for pesticide control although the fumigant is an ozone-depleting substance (Sakudo et al., 2017). In this respect, safe and effective alternative technology is needed to protect crops from pathogens without using biocides.
New intervention technology, cold plasma (CP) was reported to achieve more desirable inactivation of different microbial species without comprising food product quality (Jiang et al., 2017; Charoux et al., 2020). Cold plasma is an ionized gas characterized by active particles such as electrons, ions, free radicals and atoms that is produced by applying energy to a gas or a mixed system with gas (Han et al., 2019; Zhao et al., 2020). Severe bombardment by CP reactive species provokes surface lesions of the microorganism living cells (Chizoba Ekezie et al., 2017). The chemical species of plasma responsible for microorganism inactivation are primarily active radicals, which also tend to react with food components via physical and chemical routes (Misra, 2016). The advantage of cold plasma treatment over conventional methods includes non-thermal, non-toxic, in-package, rare side-effect since cold plasma could be performed at atmospheric conditions (Zhao et al., 2020).