title: Inactivation of Staphylococcus aureus by pulsed UV-light sterilization.
abstract: Pulsed UV light is a novel technology to inactivate pathogenic and spoilage microorganisms in a short time. The efficacy of pulsed UV light (5.6 J/cm2 per pulse) for the inactivation of Staphylococcus aureus as suspended or agar seeded cells was investigated. A 12-, 24-, or 48-ml cell suspension in buffer was treated under pulsed UV light for up to 30 s, and 0.1 ml of sample was surface plated on Baird-Parker agar and incubated at 37 degrees C for 24 h to determine log reductions. Also, 0.1 ml of cell suspension in peptone water was surface plated on Baird-Parker agar plates, and the plates were treated under pulsed UV light for up to 30 s. The treated and untreated plates were incubated in the conditions described above. A 7- to 8-log CFU/ml reduction was observed for suspended and agar-seeded cells treated for 5 s or longer. In the case of suspended cells, the sample depth, time, treatment, and interaction were significant (P < 0.05). In the case of agar-seeded cells, the treatment time was significant (P < 0.05). Our results clearly indicate that pulsed UV technology has potential for the inactivation of pathogenic microorganisms.
authors.affiliation: Department of Agricultural and Biological Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Kathiravan
authors.initials: K
authors.lastname: Krishnamurthy
authors.forename: Ali
authors.initials: A
authors.lastname: Demirci
authors.forename: Joseph
authors.initials: J
authors.lastname: Irudayaraj
mesh_terms: D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D005514:Food Irradiation; D005516:Food Microbiology; D006801:Humans; D013211:Staphylococcus aureus / Q000528:radiation effects*; D013696:Temperature; D013997:Time Factors; D014466:Ultraviolet Rays