Antimicrobial Treatment of Escherichia coli and Staphylococcus aureus in Herbal Tea Using Low-Temperature Plasma

• DOI: 10.4315/0362-028x.jfp-18-062
• Publication Date: 2018-08-15T13:53:13Z
• Authors: Artit Chingsungnoen; Sujira Maneerat; Poramate Chunpeng; Phitsanu Poolchar...; Rachanee Nam-Matra
• Keywords: Staphylococcus aureus; Microbial Viability; 0404 agricultural biotechnology; Anti-Infective Agents; Plasma Gases; Escherichia coli; Temperature; 04 agricultural and veterinary sciences; 0405 other agricultural sciences; Teas, Herbal; 6. Clean water; 3. Good health

A low-pressure capacitively coupled discharge was used to study antimicrobial treatment in herbal tea. Ambient air with a relative humidity of 40% was used as a precursor gas and fed into the chamber via a perforated power electrode. An electrical discharge plasma was produced at a radio frequency of 10 kHz and power of 80 W. The operating pressure during treatment was kept constant at 260 Pa. The target microorganisms, Escherichia coli and Staphylococcus aureus, isolated from the herbal tea were inoculated on nutrient agar petri dishes and exposed to the plasma for 0.5, 1.0, 1.5, and 2.0 min. All treatments were carried out in triplicate for different exposure times to calculate the D-value by the enumeration method. D-values of 0.73 and 0.67 min were obtained corresponding to E. coli and S. aureus reduction, respectively.