title: Chlorine inactivation of Salmonella Kentucky isolated from chicken carcasses: evaluation of strain variation.
abstract: The current study was undertaken to evaluate chlorine resistance among strains of Salmonella Kentucky isolated from chicken carcasses. Selected strains (n = 8) were exposed to 30 ppm of chlorine in 10% buffered peptone water (pH 7.4) for 0 to 10 min at 4°C and 150 rpm. The initial level (mean ± SD) of Salmonella Kentucky was 6.18 ± 0.09 log CFU/ml and did not differ (P > 0.05) among strains. A two-way analysis of variance indicated that the level of Salmonella Kentucky in chlorinated water was affected (P < 0.05) by a time by strain interaction. Differences among strains increased as a function of chlorine exposure time. After 10 min of chlorine exposure, the most resistant strain (SK145) was 5.63 ± 0.54 log CFU/ml, whereas the least resistant strain (SK275) was 3.07 ± 0.29 log CFU/ml. Significant differences in chlorine resistance were observed for most strain comparisons. Death of Salmonella Kentucky was nonlinear over time and fitted well to a power law model with a shape parameter of 0.34 (concave upward). Time (minutes) for a 1-log reduction of Salmonella Kentucky differed (P < 0.05) among strains: >10 min for SK145, 6.0 min for SK254, 1.5 min for SK179, and 0.3 to 0.65 min for other strains. Results of this study indicate that strain is an important variable to include in models that predict changes in levels of Salmonella Kentucky in chlorinated water.
authors.affiliation: Food Science and Technology Program, Department of Agriculture, Food and Resource Sciences, Room 2111, Center for Food Science and Technology, University of Maryland Eastern Shore, Princess Anne, Maryland 21853, USA.
authors.forename: T M
authors.initials: TM
authors.lastname: Mohamed
authors.affiliation: Food Science and Technology Program, Department of Agriculture, Food and Resource Sciences, Room 2111, Center for Food Science and Technology, University of Maryland Eastern Shore, Princess Anne, Maryland 21853, USA. sparveen@umes.edu.
authors.forename: S
authors.initials: S
authors.lastname: Parveen
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Residue Chemistry and Predictive Microbiology Research Unit, Room 2111, Center for Food Science and Technology, University of Maryland Eastern Shore, Princess Anne, Maryland 21853, USA.
authors.forename: J B
authors.initials: JB
authors.lastname: Ludwig
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Residue Chemistry and Predictive Microbiology Research Unit, Room 2111, Center for Food Science and Technology, University of Maryland Eastern Shore, Princess Anne, Maryland 21853, USA.
authors.forename: T P
authors.initials: TP
authors.lastname: Oscar
mesh_terms: D000818:Animals; D002645:Chickens; D002713:Chlorine / Q000494:pharmacology*; D015169:Colony Count, Microbial; D024881:Drug Resistance, Bacterial; D005506:Food Contamination / Q000032:analysis; D007629:Kentucky; D008460:Meat / Q000382:microbiology*; D050296:Microbial Viability / Q000187:drug effects; D019779:Salmonella enterica / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*
chemical_list: D002713:Chlorine