ARS | Publication request: Cold plasma reduces Salmonella on sliced roma tomatoes: efficacy of air versus nitrogen

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 25, 2012
Publication Date: June 25, 2012
Citation: Niemira, B.A. 2012. Cold plasma reduces Salmonella on sliced roma tomatoes: efficacy of air versus nitrogen. Meeting Abstract.Institute of Food Technologies Annual Meeting., Las Vegas, NV., June 25-28, 2012., Volume 1, Page 1.

Technical Abstract: A rapid, waterless, contact-free method of decontamination for tomatoes and tomato slices is of interest to processors and the food service industry. Cold plasma is a novel antimicrobial treatment for fresh and fresh-cut fruits and vegetables. Slices of Roma tomatoes were spot inoculated with three different isolates of Salmonella: S. Enteritidis PT30, S. Anatum and S. Stanley. Inoculation spots were in the center of the tomato slices and around the perimeter. The inoculated slices were treated with cold plasma from a gliding arc plasma jet operating at a pulse frequency of 47kHz, with a power consumption of 549W. The treatment variables were: 1) distance from the cold plasma jet (2 cm, 4 cm or 6 cm); 2) duration of rapid exposure (10 s or 20 s); 3) feed gas used to generate the cold plasma (filtered air or nitrogen). Rapid treatments with cold plasma were able to significantly reduce Salmonella on sliced Roma tomatoes, with the greatest reduction being 0.712 log cfu/g. For all isolates tested, the greatest efficacy was seen at the closest spacing (2 cm). Treatment time of 20 s was significantly more effective than 10 s at a spacing of 2 cm, but was not significantly more effective at 4 cm or 6 cm. Air was generally more effective as a cold plasma feed gas for S. Enteritidis PT30 and S. Anatum, but not for S. Stanley. In general, S. Stanley was more sensitive to cold plasma under both air and nitrogen. These results indicate that cold plasma has potential as a nonthermal antimicrobial treatment for sliced tomatoes.