Effects of the Cold Atmospheric Plasma Treatment Technology on Staphylococcus Aureus and Escherichia Coli Populations in Raw Milk

Document Type : Research Paper


1 Department of Food Hygiene, Faculty of Veterinary Medicine, Science and Research Branch, Islamic Azad University, Tehran, Iran.

2 Department of Biology, Faculty of Converging Sciences and Technologies, Islamic Azad University, Science and Research Branch, Tehran, Iran

3 Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran, Iran


Today, various sterilization methods are used for the removal of microorganisms, some of which are based on thermal methods that have negative effects on the physicochemical properties of milk. The present study aimed to investigate the effects of cold plasma at atmospheric pressure on the population of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) in raw milk. Initially, a plasma jet filled with argon gas was used to evaluate the antibacterial effects of cold plasma. Following that, pasteurized milk samples (1.5% and 3% fat) were infected with standard strains of E. coli and coagulase-positive S. aureus and irradiated with cold plasma at the frequency of 22, 28, and 33 kHz and voltage of 20, 12.5, and 10 kV for five minutes. The results of statistical analysis and Tukey’s test indicated that the E. coli and S. aureus microbial load was significantly lower in the 1.5% fat milk compared to the control group (P<0.05). In addition, the milk samples exposed to plasma at 20 kV and 28 kHz showed the most significant reduction in the number of E. coli bacteria compared to the control samples (P<0.05). The milk samples exposed to 10 kV and 33 kHz also showed the most significant reduction in the S. aureus microbial load. According to the results, cold plasma could decrease the microbial load of milk containing 1.5% fat more significantly compared to the 3% fat milk. Therefore, plasma could be a proper alternative to thermal decontamination methods for raw milk. However, its application requires further studies to determine the intensity and duration of the exposure of microorganisms to cold plasma at atmospheric pressure.


  1. Karimnezhad F, Razavilar V, Anvar AA, Eskandari S. Study the antimicrobial effects of chitosan-based edible film containing the Trachyspermum ammi essential oil on shelf-life of chicken meat. Microbiol Res. 2017;8(2):7226.
  2. Foroughi S, Dabbagh MA, Ahari H, Akbarein H, Anvar A, Aghazadeh MM, et al. A Survey on the shelf life extension of foods with nanofilms. 2011; 81-6.
  3. Namvar Rad M, Razavilar V, Anvar SAA, Akbari‐Adergani B. Selected bio‐physical factors affecting the efficiency of Bifidobacterium animalis lactis and Lactobacillus delbrueckii bulgaricus to degrade aflatoxin M1 in artificially contaminated milk. J Food Saf. 2018; 38(4): e12463.
  4. Poghossian A, Geissler H, Schöning MJ. Rapid methods and sensors for milk quality monitoring and spoilage detection. Biosens Bioelectron. 2019; 140: 111272.
  5. Júnior JR, De Oliveira A, Silva FdG, Tamanini R, De Oliveira A, Beloti V. The main spoilage-related psychrotrophic bacteria in refrigerated raw milk. J Dairy Sci. 2018;101(1):75-83.
  6. Maes S, Heyndrickx M, Vackier T, Steenackers H, Verplaetse A, Reu Kd. Identification and spoilage potential of the remaining dominant microbiota on food contact surfaces after cleaning and disinfection in different food industries. J Food Prot. 2019;82(2):262-75.
  7. Alves de Aguiar Bernardo Y, Kaic AlvesdDo Rosario D, Adam Conte-Junior C. Ultrasound on Milk Decontamination: Potential and Limitations Against Foodborne Pathogens and Spoilage Bacteria. Food Rev Int. 2021:1-14.
  8. Wedel C, Konschelle T, Dettling A, Wenning M, Scherer S, Hinichs J. Thermally induced milk fouling: Survival of thermophilic spore formers and potential of contamination. Int Dairy J. 2020;101:104582.
  9. Coutinho NM, Silveira MR, Rocha RS, Moraes J, Ferreira MVS, Pimentel TC, et al. Cold plasma processing of milk and dairy products. Trends Food Sci Technol. 2018; 74: 56-68.
  10. Bourke P, Ziuzina D, Boehm D, Cullen PJ, Keener K. The potential of cold plasma for safe and sustainable food production. Trends in biotechnology. 2018;36(6):615-26.
  11. Pankaj SK, Wan Z, Keener KM. Effects of cold plasma on food quality: A review. Foods. 2018;7(1):4.
  12. Ekezie F-GC, Sun D-W, Cheng J-H. A review on recent advances in cold plasma technology for the food industry: Current applications and future trends. Trends Food Sci Technol. 2017; 69:46-58.
  13. Mandal R, Singh A, Singh AP. Recent developments in cold plasma decontamination technology in the food industry. Trends Food Sci Technol. 2018; 80:93-103.
  14. Pankaj SK, Keener KM. Cold plasma: Background, applications and current trends. Curr Opin Food Sci. 2017; 16:49-52.
  15. Laroussi M. Cold plasma in medicine and healthcare: The new frontier in low temperature plasma applications. Front Phys. 2020; 8:74.
  16. Pervez M, Begum A, Laroussi M. Plasma based sterilization: Overview and the stepwise inactivation process of microbial by non-thermal atmospheric pressure plasma jet. Int J Eng Technol. 2014;14(7).
  17. Panchal H, Patel J, Chaudhary S. A comprehensive review of solar milk pasteurization system. J Sol Energy Eng. 2018;140(1).
  18. Ng SW, Lu P, Rulikowska A, Boehm D, O'Neill G, Bourke P. The effect of atmospheric cold plasma treatment on the antigenic properties of bovine milk casein and whey proteins. Food Chem. 2021; 342:128283.
  19. ASLAN Y. The Effect of Dielectric Barrier Discharge Plasma Treatment on the Microorganisms Found in Raw Cow’s Milk. Türkiye Tarım Araşt Derg. 2016;3(2):169-73.
  20. Hajhoseini A, Sharifan A, Yousefi H. Effects of atmospheric cold plasma on microbial growth of Listeria innocua and Staphylococcus aureus in ready-to-eat fish products. Iran J Fish Sci. 2020;19(1):262-71.
  21. Jayasena DD, Kim HJ, Yong HI, Park S, Kim K, Choe W, et al. Flexible thin-layer dielectric barrier discharge plasma treatment of pork butt and beef loin: Effects on pathogen inactivation and meat-quality attributes. Food Microbiol. 2015; 46:51-7.
  22. Hong Y, Kang J, Lee H, Uhm H, Moon E, Park Y. Sterilization effect of atmospheric plasma on Escherichia coli and Bacillus subtilis endospores. Lett Appl Microbiol. 2009;48(1):33-7.
  23. Basaran P, Basaran-Akgul N, Oksuz L. Elimination of Aspergillus parasiticus from nut surface with low pressure cold plasma (LPCP) treatment. Food Microbiol. 2008;25(4):626-32.
  24. Afshari R, Hosseini H. Non-thermal plasma as a new food preservation method, its present and future prospect. Arch Biol Sci. 2014;5(1).
  25. Wang R, Nian W, Wu H, Feng H, Zhang K, Zhang J, et al. Atmospheric-pressure cold plasma treatment of contaminated fresh fruit and vegetable slices: inactivation and physiochemical properties evaluation. Eur Phys J D. 2012;66(10):1-7.
  26. Laroussi M. Nonthermal decontamination of biological media by atmospheric-pressure plasmas: review, analysis, and prospects. IEEE Trans Plasma Sci. 2002;30(4):1409-15.
  27. Fidler N, Sauerwald TU, Koletzko B, Demmelmair H. Effects of human milk pasteurization and sterilization on available fat content and fatty acid composition. J Pediatr Gastroenterol Nutr. 1998; 27,3:317-22.
  28. Senhaji AF, Loncin M. The protective effect of fat on the heat resistance of bacteria (I).  Int J Food Sci Technol. 1977;123:203-16.
  29. Niemira BA. Cold plasma decontamination of foods. Annu Rev Food Sci Technol. 2012;3:125-42.
  30. Rezaei Mehr A, Sohbatzadeh F, Siadati Sen, Alavi Sa. Use of cold plasma atmospheric pressure in Escherichia coli disinfection of milk. Third National Conference on Food Science and Industry.2014:10(11)80-86.
  31. Hosseinzadeh Ca, Deylami M, Sohbatzadeh F, Siadati S. The effects of scanning cold atmospheric plasma jet on bovin’s milk and its inoculated candida albicans. 2017; 103-11.
  32. Gurol C, Ekinci F, Aslan N, Korachi M. Low temperature plasma for decontamination of E. coli in milk. Int J Food Microbiol. 2012;157(1):1-5.
  33. Tyczkowska-Sieron E, Markiewicz J, Grzesiak B, Krukowski H, Glowacka A, Tyczkowski J. Cold atmospheric plasma inactivation of Prototheca zopfii isolated from bovine milk. J Dairy sci. 2018;101(1):118-22.
  34. Wu X, Luo Y, Zhao F, Mu G. Influence of dielectric barrier discharge cold plasma on physicochemical property of milk for sterilization. Plasma Process Polym. 2021;18(1):1900219.