Evaluation of Radiant Catalytic Ionization in Reducing Escherichia Coli, Listeria Innocua and Salmonella Typhimurium on Representative Food Contact Surfaces

Abstract

Escherichia coli, Listeria spp. and Salmonella typhimurium are common food pathogens and responsible for frequent and widespread outbreaks of foodborne illness annually. This study examines the potential of radiant catalytic ionization (RCI) as a food decontamination technology through its reduction of inoculations of these bacteria on representative food items (apples, cantaloupes, and spinach). RCI exposure resulted in ≥99% reduction in the recovery of these bacteria within a 90-min exposure, with two exceptions (E. coli and S. typhimurium inoculated on cantaloupe: 94% reduction; 88% reduction, respectively). When E. coli, L. innocua and S. typhimurium were inoculated onto apple slices, the percentages remaining after exposure to RCI for 0, 30, 60 and 90 min were: 100, 2, 0, 0; 100, 30, 9, 0.01; and 100, 21, 0.004, 0.02, respectively. When E. coli, L. innocua and S. typhimurium were inoculated onto the rough outer skin of cantaloupes, the percentages remaining after exposure to RCI for 0, 30, 60 and 90 min were: 100, 19, 15, 6; 100, 9, 10, 1; and 100, 24, 22, 12, respectively. When E. coli, L. innocua and S. typhimurium were inoculated onto spinach leaves, the percentages remaining after exposure to RCI for 0, 30, 60 and 90 min were: 100, 16, 0.001, 0.002; 100, 19, 11, 0.005; and 100, 0.007, 0, 0, respectively (SE = ± 0.1 maximum). These results indicate that RCI is an effective technology for reducing foodborne pathogens.

The Antimicrobial Effect of Radiant Catalytic Ionization on the Bacterial Attachment and Biofilm Formation by Selected Foodborne Pathogens under Refrigeration Conditions

“…According to Ortega et al [25], the reduction of different microorganisms, including foodborne pathogens, on stainless steel surfaces subjected to 24 h of RCI treatment reached at least 90%. RCI efficacy against Salmonella on food contact surfaces and animal food products was also confirmed [28,40]. The present research showed the inhibition of C. jejuni, L. monocytogenes, and S. Enteritidis strains on a glass surface after RCI treatment.…”

“…The antimicrobial efficiency of RCI is attributed to the cell damaging effect of oxidative gases, including ozone and peroxide, generated by the RCI cell [25,28]. The inhibition of pathogenic microorganisms on various surfaces was confirmed by our previous studies [8,26,27].…”

“…Skowron et al [27] noted a similar level of L. monocytogenes and S. Enteritidis reduction after RCI treatment. Mannozzi et al [28] observed lower sensitivity of Escherichia coli, as compared to Listeria innocua and S. Typhimurium after 60 min of RCI treatment; however, after 90 min no differences were reported. In the present study, in most cases, we observed no significant differences in the resistance to RCI exposure between C. jejuni, L. monocytogenes, and S. Enteritidis.…”

“…The time of ionization affects the irradiation efficiency and, generally, the greater reduction is associated with the longer time exposure [25,28,44]. According to Grinshpun et al [45], approximately 75% of B. subtilis spores were inactivated in 10 min, and about 90% after 30 min of photocatalytic oxidation.…”

Antimicrobial effect of radiant catalytic ionization

“…The photocatalysis process with UV radiation and TiO 2 as a catalyst as a method of inactivation of microorganisms (Lactobacillus acidophilus, Saccharomyces cerevisiae cerevisiae and Escherichia coli) in water was first used by Matsunaga et al (1988). The effectiveness of photocatalysis for water sterilization has been demonstrated by many researchers (Saito et al 1992;Wei et al 1994;Sunada et al 1998;Maness et al 1999;Marug an et al 2008). The results of these studies were satisfactory as they were characterized by a high level of bacterial inactivation.…”