title: Microbial Indicator Profiling of Fresh Produce and Environmental Samples from Farms and Packing Facilities in Northern Mexico.
abstract: To compare microbiological indicator and pathogen contamination among different types of fresh produce and environmental samples along the production chain, 636 samples of produce (rinsates from cantaloupe melons, jalapeño peppers, and tomatoes) and environmental samples (rinsates from hands of workers, soil, and water) were collected at four successive steps in the production process (from the field before harvest through the packing facility) on 11 farms in northern Mexico during 2011 and 2012. Samples were assayed for enteric pathogens (Escherichia coli O157:H7, other Shiga toxigenic E. coli, Salmonella, and Listeria monocytogenes) and microbial indicators (coliforms, other E. coli strains, and Enterococcus spp.). Salmonella was the only pathogen detected; it was found in one preharvest jalapeño sample (detection limits: 0.0033 CFU/ml in produce and hand samples, 0.0013 CFU/ml in water, and 0.04 CFU/g in soil). Microbial indicator profiles for produce, worker hands, and soil from jalapeño and tomato farms were similar, but cantaloupe farm samples had higher indicator levels (P < 0.05 for all comparisons) on fruit (6.5, 2.8, and 7.2 log CFU per fruit) and hands (6.6, 3.1, and 7.1 log CFU per hand) for coliforms, E. coli, and Enterococcus, respectively, and lower E. coli levels in soil (<1 CFU/g). In water from tomato farms, E. coli indicators were significantly more prevalent (70 to 89% of samples were positive; P = 0.01 to 0.02), and geometric mean levels were higher (0.3 to 0.6 log CFU/100 ml) than those in cantaloupe farm water (32 to 38% of samples were positive, geometric mean <1 CFU/100 ml). Microbial indicators were present during all production steps, but prevalence and levels were generally highest at the final on-farm production step (the packing facility) (P < 0.03 for significant comparisons). The finding that microbial contamination on produce farms is influenced by produce type and production step can inform the design of effective approaches to mitigate microbial contamination.
authors.affiliation: Departamento de Microbiología e Inmunología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo Léon, Apostado Postal 124-F, San Nicolás, Nuevo Léon 66451, México.
authors.forename: Norma
authors.initials: N
authors.lastname: Heredia
authors.affiliation: Departamento de Microbiología e Inmunología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo Léon, Apostado Postal 124-F, San Nicolás, Nuevo Léon 66451, México.
authors.forename: Cindy
authors.initials: C
authors.lastname: Caballero
authors.affiliation: Departamento de Microbiología e Inmunología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Apostado Postal 124-F, San Nicolás, Nuevo León 66451, México.
authors.forename: Carmen
authors.initials: C
authors.lastname: Cárdenas
authors.affiliation: Departamento de Microbiología e Inmunología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Apostado Postal 124-F, San Nicolás, Nuevo León 66451, México.
authors.forename: Karina
authors.initials: K
authors.lastname: Molina
authors.affiliation: Departamento de Microbiología e Inmunología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Apostado Postal 124-F, San Nicolás, Nuevo León 66451, México.
authors.forename: Rafael
authors.initials: R
authors.lastname: García
authors.affiliation: Departamento de Microbiología e Inmunología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Apostado Postal 124-F, San Nicolás, Nuevo León 66451, México.
authors.forename: Luisa
authors.initials: L
authors.lastname: Solís
authors.affiliation: Hubert Department of Global Health, Rollins School of Public Health, Emory University, 1518 Clifton Road N.E., Atlanta, Georgia 30322, USA.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Burrowes
authors.affiliation: Hubert Department of Global Health, Rollins School of Public Health, Emory University, 1518 Clifton Road N.E., Atlanta, Georgia 30322, USA. faith.bartz@gmail.com.
authors.forename: Faith E
authors.initials: FE
authors.lastname: Bartz
authors.affiliation: Hubert Department of Global Health, Rollins School of Public Health, Emory University, 1518 Clifton Road N.E., Atlanta, Georgia 30322, USA.
authors.forename: Anna Fabiszewski
authors.initials: AF
authors.lastname: de Aceituno
authors.affiliation: Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, 339-A Schaub Hall, Raleigh, North Carolina 27695, USA.
authors.forename: Lee-Ann
authors.initials: LA
authors.lastname: Jaykus
authors.affiliation: Departamento de Microbiología e Inmunología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Apostado Postal 124-F, San Nicolás, Nuevo León 66451, México.
authors.forename: Santos
authors.initials: S
authors.lastname: García
authors.affiliation: Hubert Department of Global Health, Rollins School of Public Health, Emory University, 1518 Clifton Road N.E., Atlanta, Georgia 30322, USA.
authors.forename: Juan
authors.initials: J
authors.lastname: Leon
mesh_terms: D015169:Colony Count, Microbial; D019453:Escherichia coli O157; D000072480:Farms; D005516:Food Microbiology; D005638:Fruit / Q000382:microbiology; D008800:Mexico; D012475:Salmonella