title: Persistence of Indicator and Pathogenic Microorganisms in Broccoli following Manure Spreading and Irrigation with Fecally Contaminated Water: Field Experiment.
abstract: In 2011 and 2012, trials consisting of experimental plots were carried out to evaluate the presence of pathogenic (Listeria monocytogenes, Salmonella) and prevalence of indicator (Escherichia coli) microorganisms in broccoli fertilized with liquid hog manure or mineral fertilizers and irrigated zero, one, or two times with E. coli-contaminated water. In 2011, results showed that E. coli contamination in broccoli heads was affected by the interval between irrigation and sampling (P = 0.0236), with a significant decrease between the first and third day following irrigation (P = 0.0064). In 2012, irrigation frequency significantly increased E. coli prevalence in broccoli samples (P = 0.0499). In 2012, E. coli counts in the soil were significantly influenced by the type of fertilizer applied, as plots receiving liquid hog manure showed higher bacterial counts (P = 0.0006). L. monocytogenes was recovered in one broccoli sample, but geno-serogrouping differentiated the isolate from those recovered in manure and irrigation water. The L. monocytogenes serogroup IIA, pulsotype 188 strain was found in six soil samples and in irrigation water applied 5 days before soil sampling. This study highlights the link between E. coli levels in irrigation water, irrigation frequency, and interval between irrigation and harvest on produce contamination. It also demonstrates that L. monocytogenes introduced into the soil following irrigation can persist for up to 5 days.
authors.affiliation: Research and Development Institute for the Agri-Environment (IRDA), 335 Vingt-Cinq East Road, Saint-Bruno-de-Montarville, Québec, Canada J3V 0G7. mylene.genereux@irda.qc.ca.
authors.forename: Mylène
authors.initials: M
authors.lastname: Généreux
authors.affiliation: Research and Development Institute for the Agri-Environment (IRDA), 335 Vingt-Cinq East Road, Saint-Bruno-de-Montarville, Québec, Canada J3V 0G7.
authors.forename: Marie Jo
authors.initials: MJ
authors.lastname: Breton
authors.affiliation: OIE Reference Laboratory for Escherichia coli (EcL), Faculty of Veterinary Medicine, Université de Montréal, 3200 Sicotte Street, Saint-Hyacinthe, Québec, Canada J2S 2M2.
authors.forename: John Morris
authors.initials: JM
authors.lastname: Fairbrother
authors.affiliation: NSERC Industrial Research Chair in Meat Safety, Faculty of Veterinary Medicine, Université de Montréal, 3200 Sicotte Street, Saint-Hyacinthe, Québec, Canada J2S 2M2.
authors.forename: Philippe
authors.initials: P
authors.lastname: Fravalo
authors.affiliation: Research and Development Institute for the Agri-Environment (IRDA), 335 Vingt-Cinq East Road, Saint-Bruno-de-Montarville, Québec, Canada J3V 0G7.
authors.forename: Caroline
authors.initials: C
authors.lastname: Côté
mesh_terms: D001937:Brassica / Q000382:microbiology*; D015169:Colony Count, Microbial; D004926:Escherichia coli / Q000302:isolation & purification; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology; D008089:Listeria monocytogenes / Q000302:isolation & purification; D008372:Manure / Q000382:microbiology*; D012475:Salmonella / Q000302:isolation & purification; D012988:Soil Microbiology; D014871:Water Microbiology
chemical_list: D008372:Manure