title: Microbial quality of irrigation water used in leafy green production in Southern Brazil and its relationship with produce safety.
abstract: Irrigation water has been recognized as an important microbial risk factor for fruits and vegetables in many production areas, but there is still a lack of information about how the microbiological quality of different irrigation water sources and climatic conditions influence the safety of vegetables produced in Brazil. This study evaluated the distribution of generic E. coli and the prevalence of E. coli O157:H7 in two different water sources (ponds and streams bordering farmlands and urban areas) used for irrigation and on commercially produced lettuces in Southern Brazil. We also evaluated the effect of agricultural factors and meteorological conditions in the potential contamination of water and produce samples. A longitudinal study was conducted on four farms during a year (July 2014 to August 2015). The results showed generic E. coli prevalence of 84.8% and 38.3% in irrigation water samples and on lettuces, respectively, indicating irrigation water as an important source of contamination of lettuces. No significant differences were detected in the counts of E. coli between the two different surface water sources. The climatic conditions, particularly rainfall and environmental temperature, have influenced the high concentration of E. coli. The highest loads of E. coli in irrigation water and on lettuces were found during the warmest time of the year. E. coli O157:H7 was detected by qualitative polymerase chain reaction (qPCR) in 13 water samples but only 4 were confirmed by isolation in culture media.
authors.affiliation: Laboratório de Microbiologia e Controle de Alimentos, Instituto de Ciência e Tecnologia de Alimentos, Universidade Federal do Rio Grande do Sul (ICTA/UFRGS), Av. Bento Gonçalves 9.500, prédio 43212, Campos do Vale, Agronomia, CEP: 91501-970, Porto Alegre, RS, Brazil.
authors.forename: Luana Tombini
authors.initials: LT
authors.lastname: Decol
authors.affiliation: Laboratório de Microbiologia e Controle de Alimentos, Instituto de Ciência e Tecnologia de Alimentos, Universidade Federal do Rio Grande do Sul (ICTA/UFRGS), Av. Bento Gonçalves 9.500, prédio 43212, Campos do Vale, Agronomia, CEP: 91501-970, Porto Alegre, RS, Brazil.
authors.forename: Letícia Sopeña
authors.initials: LS
authors.lastname: Casarin
authors.affiliation: Laboratório de Microbiologia e Controle de Alimentos, Instituto de Ciência e Tecnologia de Alimentos, Universidade Federal do Rio Grande do Sul (ICTA/UFRGS), Av. Bento Gonçalves 9.500, prédio 43212, Campos do Vale, Agronomia, CEP: 91501-970, Porto Alegre, RS, Brazil.
authors.forename: Claudia Titze
authors.initials: CT
authors.lastname: Hessel
authors.affiliation: Laboratório de Microbiologia e Controle de Alimentos, Instituto de Ciência e Tecnologia de Alimentos, Universidade Federal do Rio Grande do Sul (ICTA/UFRGS), Av. Bento Gonçalves 9.500, prédio 43212, Campos do Vale, Agronomia, CEP: 91501-970, Porto Alegre, RS, Brazil.
authors.forename: Ana Carolina Fösch
authors.initials: ACF
authors.lastname: Batista
authors.affiliation: Research Group on Quality, Safety and Bioactivity of Plant Foods, Department of Food Science and Technology, CEBAS-CSIC, Campus Universitario de Espinardo, 30100, Murcia, Spain. Electronic address: aallende@cebas.csic.es.
authors.forename: Ana
authors.initials: A
authors.lastname: Allende
authors.affiliation: Laboratório de Microbiologia e Controle de Alimentos, Instituto de Ciência e Tecnologia de Alimentos, Universidade Federal do Rio Grande do Sul (ICTA/UFRGS), Av. Bento Gonçalves 9.500, prédio 43212, Campos do Vale, Agronomia, CEP: 91501-970, Porto Alegre, RS, Brazil.
authors.forename: Eduardo César
authors.initials: EC
authors.lastname: Tondo
mesh_terms: D057914:Agricultural Irrigation / Q000592:standards*; D058491:Bacterial Load; D001938:Brazil; D002980:Climate; D015169:Colony Count, Microbial; D019453:Escherichia coli O157 / Q000235:genetics / Q000302:isolation & purification; D000072480:Farms; D005516:Food Microbiology; D059022:Food Safety / Q000379:methods*; D018545:Lactuca / Q000382:microbiology; D008137:Longitudinal Studies; D018515:Plant Leaves / Q000382:microbiology*; D060888:Real-Time Polymerase Chain Reaction; D014675:Vegetables / Q000382:microbiology*; D014871:Water Microbiology
keywords: Foodborne pathogens; Fresh produce; Indicator microorganisms; Irrigation water; Primary production