Cold plasma-activated hydrogen peroxide aerosol inactivates Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria innocua and maintains quality of grape tomato, spinach and cantaloupe.
The purpose of this study was to investigate the efficacy of aerosolized hydrogen peroxide in inactivating bacteria and maintaining quality of grape tomatoes, baby spinach leaves and cantaloupes. Stem scars and smooth surfaces of tomatoes, spinach leaves, and cantaloupe rinds, inoculated with Escherichia coli O157:H7, Salmonella Typhimurium and Listeria innocua, were treated for 45s followed by additional 30min dwell time with hydrogen peroxide (7.8%) aerosols activated by atmospheric cold plasma. Non-inoculated samples were used to study the effects on quality and native microflora populations. Results showed that two ranges of hydrogen peroxide droplets with mean diameters of 40nm and 3.0μm were introduced into the treatment chamber. The aerosolized hydrogen peroxide treatment reduced S. Typhimurium populations by 5.0logCFU/piece, and E. coli O157:H7 and L. innocua populations from initial levels of 2.9 and 6.3logCFU/piece, respectively, to non-detectable levels (detection limit 0.6logCFU/piece) on the smooth surface of tomatoes. However, on the stem scar area of tomatoes, the reductions of E. coli O157:H7, S. Typhimurium, and L. innocua were only 1.0, 1.3, and 1.3 log, respectively. On the cantaloupe rind, the treatment reduced populations of E. coli O157:H7, S. Typhimurium and L. innocua by 4.9, 1.3, and 3.0logCFU/piece, respectively. Under the same conditions, reductions achieved on spinach leaves were 1.5, 4.2 and 4.0 log for E. coli O157:H7, S. Typhimurium and L. innocua, respectively. The treatments also significantly reduced native aerobic plate count, and yeasts and mold count of tomato fruits and spinach leaves. Furthermore, firmness and color of the samples were not significantly affected by the aerosolized hydrogen peroxide. Overall, our results showed that the efficacy of aerosolized hydrogen peroxide depended on type of inoculated bacteria, location of bacteria and type of produce items, and aerosolized hydrogen peroxide could potentially be used to sanitize fresh fruits and vegetables.
Key Laboratory of Food Nutrition and Safety (Tianjin University of Science and Technology), Ministry of Education, Tianjin 300457, China.
Yunbin
Y
Jiang
U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 E. Mermaid Lane, Wyndmoor, PA 19038, USA.
Kimberly
K
Sokorai
Center for Nanotechnology and Nanotoxicology, Harvard School of Public Health, Boston, MA 02115, USA.
Georgios
G
Pyrgiotakis
Center for Nanotechnology and Nanotoxicology, Harvard School of Public Health, Boston, MA 02115, USA.
Philip
P
Demokritou
Key Laboratory of Food Nutrition and Safety (Tianjin University of Science and Technology), Ministry of Education, Tianjin 300457, China.
Xihong
X
Li
U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 E. Mermaid Lane, Wyndmoor, PA 19038, USA.
Sudarsan
S
Mukhopadhyay
U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 E. Mermaid Lane, Wyndmoor, PA 19038, USA.
Tony
T
Jin
U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 E. Mermaid Lane, Wyndmoor, PA 19038, USA. Electronic address: xuetong.fan@ars.usda.gov.
Xuetong
X
Fan
D000336:Aerosols; D015169:Colony Count, Microbial; D028463:Cucumis melo / Q000382:microbiology*; D019453:Escherichia coli O157 / Q000187:drug effects*; D005516:Food Microbiology / Q000379:methods; D005519:Food Preservation / Q000379:methods*; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry / Q000494:pharmacology*; D008087:Listeria / Q000187:drug effects*; D018551:Solanum lycopersicum / Q000382:microbiology*; D058626:Plasma Gases / Q000737:chemistry; D012486:Salmonella typhimurium / Q000187:drug effects*; D018724:Spinacia oleracea / Q000382:microbiology*; D014675:Vegetables / Q000382:microbiology
D000336:Aerosols; D058626:Plasma Gases; D006861:Hydrogen Peroxide
Aerosolization; Foodborne pathogen; Hydrogen peroxide; Native microflora; Quality