High voltage atmospheric cold plasma treatment of fresh cantaloupe to improve safety and quality

Raw agricultural products naturally contain a diverse surface population of microbial organisms. Cantaloupes, like other agricultural products, rarely undergo antimicrobial treatment before reaching the consumer, and are most often consumed raw. Many consumers fail to wash this fruit prior to consumption, contributing to the recent outbreaks of foodborne illness (1). This, along with poor handling practices makes it a desirable model for decontamination treatments. The goal of this research was to evaluate High Voltage Atmospheric Cold Plasma (HVACP) treatment for the reduction of surface microbial load on fresh cantaloupe. HVACP is a novel in-package atmospheric cold plasma process developed at Purdue University by Keener et al. Previous research (2) has shown HVACP is effective at eliminating spores (>6 log₁₀), reducing microbial load (3-5 log₁₀ of E. coli O157:H7 on lettuce; Salmonella spp. on tomatoes and spinach (3)) while extending shelf life. It indirectly exposes packaged, sliced cantaloupe to a high voltage / low power (90 Kv / 200W) HVACP field for 180 seconds, followed by 24 hours of room temperature (21 C) storage. During the 24 hour storage the reactive gas species (RGS) generated during HVACP treatment slowly convert back to their more forms (O2 and N2). Measurements include microbial load analysis, oxygen, nitrous oxides, and ozone concentrations. Consequent analysis of the cantaloupe exocarp by BARDOT (BActerial Rapid Detection using Optical light scattering Technology), showed a 2-3 log₁₀ reduction in microbial load across treated samples and 74% reduction in microbial diversity. Results indicate that this HVACP process effectively reduces microbial populations on fresh, raw cantaloupe surfaces.