title: Prevalence of Escherichia coli O157:H7 and Salmonella on Inshell California Walnuts.
abstract: Inshell walnuts collected from California walnut handlers over four harvests were evaluated for the presence of Escherichia coli O157:H7 and Salmonella. E. coli O157:H7 was not detected in any of 2,903 375-g samples evaluated in 2011, 2012, and 2013 (<0.034% prevalence; 95% confidence interval [CI], 0 to 0.13%). Salmonella was not isolated from any of the 935 samples in 2010 (100 g evaluated; <0.11% prevalence; 95% CI, 0 to 0.41%) but was isolated from 2 of 905 (375 g; 0.22% prevalence; 95% CI, 0.061 to 0.80%), 1 of 998 (375 g; 0.10% prevalence; 95% CI, 0.018 to 0.56%), and 1 of 1,000 (375 g; 0.10% prevalence; 95% CI, 0.018 to 0.56%) samples in 2011, 2012, and 2013, respectively, for an average annual prevalence of 0.14% (375 g; 95% CI, 0.054 to 0.35%). The levels of Salmonella in positive samples determined by a modified most-probable-number (MPN) method were estimated to be 0.32 to 0.42 MPN/100 g (95% CI, 0.045 to 3.6 MPN/100 g).
authors.affiliation: Department of Food Science and Technology, University of California, Davis, One Shields Avenue, Davis, California 95616, USA.
authors.forename: Gordon R
authors.initials: GR
authors.lastname: Davidson
authors.affiliation: Department of Food Science and Technology, University of California, Davis, One Shields Avenue, Davis, California 95616, USA.
authors.forename: John C
authors.initials: JC
authors.lastname: Frelka
authors.affiliation: DFA of California, 1855 South Van Ness Avenue, Fresno, California 93721, USA.
authors.forename: Mai
authors.initials: M
authors.lastname: Yang
authors.affiliation: DFA of California, 1855 South Van Ness Avenue, Fresno, California 93721, USA.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Jones
authors.affiliation: Department of Food Science and Technology, University of California, Davis, One Shields Avenue, Davis, California 95616, USA. ljharris@ucdavis.edu.
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Harris
mesh_terms: D002140:California; D019453:Escherichia coli O157 / Q000254:growth & development / Q000302:isolation & purification*; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology; D031324:Juglans / Q000382:microbiology*; D012475:Salmonella / Q000254:growth & development / Q000302:isolation & purification*; D012703:Serotyping