title: Effectiveness of cleaners and sanitizers in killing Salmonella Newport in the gut of a free-living nematode, Caenorhabditis elegans.
abstract: Caenorhabditis elegans, a free-living nematode found in soil, has been shown to ingest human enteric pathogens, thereby potentially serving as a vector for preharvest contamination of fruits and vegetables. A study was undertaken to evaluate the efficacy of cleaners and sanitizers in killing Salmonella enterica serotype Newport in the gut of C. elegans. Adult worms were fed nalidixic acid-adapted cells of Escherichia coli OP50 (control) or Salmonella Newport for 24 h, washed, placed on paper discs, and incubated at temperatures of 4 or 20 degrees C and relative humidities of 33 or 98% for 24 h. Two commercial cleaners (Enforce and K Foam Lo) and four sanitizers (2% acetic acid, 2% lactic acid, Sanova, and chlorine [50 and 200 microg/ml]) were applied to worms for 0, 2, or 10 min. Populations of E. coli and Salmonella Newport (CFU per worm) in untreated and treated worms were determined by sonicating worms in 0.1% peptone and surface plating suspensions of released cells on tryptic soy agar containing nalidixic acid. Populations of Salmonella Newport in worms exposed to 33 or 98% relative humidity at 4 degrees or 33% relative humidity at 20 degrees C were significantly (P < or = 0.05) lower than the number surviving exposure to 98% relative humidity at 20 degrees C. In general, treatment of desiccated worms with cleaners and sanitizers was effective in significantly (P < or = 0.05) reducing the number of ingested Salmonella Newport. Results indicate that temperature and relative humidity influence the survival of Salmonella Newport in the gut of C. elegans, and cleaners and sanitizers may not eliminate the pathogen.
authors.affiliation: Center for Food Safety and Department of Food Science and Technology, University of Georgia, 1109 Experiment Street, Griffin, Georgia 30223-1797, USA.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Kenney
authors.forename: Gary L
authors.initials: GL
authors.lastname: Anderson
authors.forename: Phillip L
authors.initials: PL
authors.lastname: Williams
authors.forename: Patricia D
authors.initials: PD
authors.lastname: Millner
authors.forename: Larry R
authors.initials: LR
authors.lastname: Beuchat
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000382:microbiology*; D015169:Colony Count, Microbial; D004199:Disease Vectors; D004202:Disinfectants / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development; D005506:Food Contamination; D005516:Food Microbiology; D006813:Humidity; D019779:Salmonella enterica / Q000187:drug effects* / Q000254:growth & development; D012988:Soil Microbiology; D013696:Temperature; D014867:Water / Q000378:metabolism
chemical_list: D004202:Disinfectants; D014867:Water