title: Comparison of inactivation of Listeria monocytogenes within a biofilm matrix using chlorine dioxide gas, aqueous chlorine dioxide and sodium hypochlorite treatments.
abstract: The present research compared the effect of chlorine dioxide (CD) gas, aqueous CD and aqueous sodium hypochlorite (SHC) treatments on the inactivation of a five strain mixture of Listeria monocytogenes - containing biofilms. Four day old biofilms were developed on a stainless steel (SS 304) coupon by using a mixture of five cultures of L. monocytogenes (Scott A, N1-227, 103M, 82 and 311) using a 100% relative humidity (RH) dessicator for incubation at room temperature (22 ± 2 °C). After biofilm development, coupons were rinsed and dried for 2 h and treated with 0.3 mg/l CD gas at 75% RH, 7 mg/l of aqueous CD and 50 mg/l SHC. Initial log(10) population of biofilm cells before CD gas, aqueous CD and SHC treatment was 4.80, 5.09 and 4.95 log(10) CFU/cm(2). The Weibull model was used to fit non-linear survivor curves. Treatments and time points of 0.3 mg/l CD gas and 7 mg/l aq. CD solution were significantly different (p < 0.05). A 10 min treatment of 0.3 mg/l CD gas, 7 mg/l of aq. CD, and 50 mg/l SHC resulted in reductions of 3.21, 3.74 and 3.09 log(10) CFU/cm(2), respectively. At 10 min, all treatments were not statistically different (p > 0.05). Low levels of CD (0.3 mg/l CD gas and 7 mg/l aq. CD solution) for 10 min resulted in similar log reductions compared to 50 mg/l SHC.
authors.affiliation: Department of Food Science, Purdue University, West Lafayette, IN 47907-2009, USA.
authors.forename: Richa
authors.initials: R
authors.lastname: Vaid
authors.forename: Richard H
authors.initials: RH
authors.lastname: Linton
authors.forename: Mark T
authors.initials: MT
authors.lastname: Morgan
mesh_terms: D018441:Biofilms / Q000187:drug effects*; D017606:Chlorine Compounds / Q000737:chemistry / Q000494:pharmacology*; D004202:Disinfectants / Q000494:pharmacology*; D008089:Listeria monocytogenes / Q000187:drug effects* / Q000254:growth & development; D050296:Microbial Viability / Q000187:drug effects*; D010087:Oxides / Q000737:chemistry / Q000494:pharmacology*; D044367:Phase Transition; D012973:Sodium Hypochlorite / Q000494:pharmacology*
chemical_list: D017606:Chlorine Compounds; D004202:Disinfectants; D010087:Oxides; C025109:chlorine dioxide; D012973:Sodium Hypochlorite