*Article* **Effect of Radiant Catalytic Ionization and Ozonation on** *Salmonella* **spp. on Eggshells**

**Katarzyna Grudlewska-Buda 1, Natalia Wiktorczyk-Kapischke 1, Ewa Wałecka-Zacharska 2, Joanna Kwieci ´nska-Piróg 1, Grzegorz Gry ´n 3, Karolina Jadwiga Skowron 4, Jakub Korkus 2, Eugenia Gospodarek-Komkowka 1, Jarosław Bystro ´n 2, Anna Budzy ´nska 1, Stefan Kruszewski 5, Zbigniew Paluszak 6, Małgorzata Andrzejewska 7, Monika Wilk <sup>1</sup> and Krzysztof Skowron 1,\***


**Abstract:** Three *Salmonella enterica* strains were used in the study (serovars: *S. enteritidis*, *S. typhimurim* and *S. virchow*). This study evaluated the efficacy of radiant catalytic ionization (RCI) and ozonation against *Salmonella* spp. on eggshell (expressed as log CFU/egg). The egg surface was contaminated three different bacterial suspension (103 CFU/mL, 10<sup>5</sup> CFU/mL and 10<sup>8</sup> CFU/mL) with or without poultry manure. Experiments were conducted at 4 ◦C and 20 ◦C in three different time period: 30 min, 60 min and 120 min. Treatment with RCI reduced *Salmonella* numbers from 0.26 log CFU/egg in bacterial suspension 10<sup>8</sup> CFU/mL, 4 ◦C and 20 ◦C, with manure for 30 min to level decrease in bacteria number below the detection limit (BDL) in bacterial suspension 105 CFU/mL, 20 ◦C, with or without manure for 120 min. The populations of *Salmonella* spp. on eggs treated by ozonizer ranged from 0.20 log CFU/egg in bacteria suspension 108 CFU/mL, 20 ◦C, with manure for 30 min to 2.73 log CFU/egg in bacterial suspension 105 CFU/mL, 20 ◦C, with manure for 120 min. In all treatment conditions contamination with poultry manure decrease effectiveness the RCI and ozonation. In summary, RCI technology shows similar effectiveness to the ozonation, but it is safer for poultry plant workers and consumers.

**Keywords:** eggs; *Salmonella* spp.; radiant catalytic ionization; ozonation; disinfection
