Assessing the Biological Safety of Atmospheric Cold Plasma Treated Wheat Using Cell and Insect Models.

Agata Los,Daniela Boehm,Dana Ziuzina,Robin Van Cleynenbreugel,Paula Bourke

doi:10.3390/foods9070898

Abstract

Atmospheric cold plasma (ACP) is under investigation for an extensive range of biocontrol applications in food biosystems. However, the development of a novel intervention technology requires a thorough evaluation of the potential for negative effects and the implications for the human and animal food chains’ safety. The evaluations were performed using a contained, high-voltage, dielectric barrier discharge plasma system. The cytotoxicity of two types of food models—a liquid model (wheat model medium (WMM)) vs. a solid model (wheat grain extract (WGE)) was compared in vitro using the mammalian cell line CHO-K1. The residual toxicity of ACP treatment of grains for food purposes was assessed using the invertebrate model Tribolium castaneum, by feeding the beetles with flour produced from ACP-treated wheat grains. The cytotoxic effects and changes in the chemistry of the ACP-treated samples were more pronounced in samples treated in a liquid form as opposed to actual wheat grains. The feeding trial using T. castaneum demonstrated no negative impacts on the survivability or weight profiles of insects. Investigations into the interactions of plasma-generated species with secondary metabolites in the food matrices are necessary to ensure the safety of plasma for food applications.

Highlights

The disruptive potential of cold plasma for the safety and quality enhancement of a wide range of food products, with an emerging focus on the earlier stages of food production chains including agricultural pre-treatments for seeds, water or soil, is under increased investigation
When the cell culture media was supplemented with untreated Wheat Model Medium (WMM) at 2 or 5% (v/v), it stimulated cell growth slightly by 7.9% and 6.4%, respectively
The negative effect of supplementation with untreated wheat grain extract (WGE) on cell growth was more pronounced for all % levels, where 5% and 10% (v/v) levels significantly decreased cell growth by 22.0% and 25.7%, respectively (Figure 2b, right panel)

Summary

Introduction

The disruptive potential of cold plasma for the safety and quality enhancement of a wide range of food products, with an emerging focus on the earlier stages of food production chains including agricultural pre-treatments for seeds, water or soil, is under increased investigation. Research performed in the context of biomedical applications of plasma has demonstrated the cytotoxic properties of plasma-treated solutions (both water and more complex media, containing carbohydrates, lipids and/or proteins) in mammalian cell models [1,2]. The cytotoxic and mutagenic effects of plasma-treated, protein-based solutions and produce-based solutions have been reported [3,4,5]. Water, phosphate-buffered saline and phosphate buffer solution exposed to plasma for 10 min resulted in cell. Foods 2020, 9, 898 to plasma for 10 min resulted in cell death in more than 50% of cells [1]. Foetal bovine serum treated with plasma for 5 or 10 min caused strong growth inhibition of HeLa cells, and exhibited increased mutagenic potential death in more than 50%

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