title: Contamination of tomatoes with coliforms and Escherichia coli on farms and in markets of northwest Nigeria.
abstract: Although recent reports indicated that produce contamination with foodborne pathogens is widespread in Nigeria, the sources and magnitude of microbial contamination of fruits and vegetables on farms and in markets have not been thoroughly identified. To ascertain possible pathways of contamination, the frequency and magnitude of coliform and Escherichia coli contamination of tomatoes produced in northwest Nigeria was assessed on farms and in markets. Eight hundred twenty-six tomato fruit samples and 36 irrigation water samples were collected and assessed for fecal indicator organisms. In addition, the awareness and use of food safety practices by tomato farmers and marketers were determined. Median concentration of coliforms on all field- and market-sourced tomato fruit samples, as well as in irrigation water sources, in Kaduna, Kano, and Katsina states exceeded 1,000 most probable number (MPN) per g. Median E. coli counts from 73 (17%) of 420 field samples and 231 (57%) of 406 market tomato fruit samples exceeded 100 MPN/g. Median E. coli concentrations on tomato fruits were higher (P < 0.01) in the rainy season (2.45 Log MPN/g), when irrigation was not practiced than in the dry (1.10 Log MPN/g) and early dry (0.92 Log MPN/g) seasons. Eighteen (50%) of 36 irrigation water samples had E. coli counts higher than 126 MPN/100 ml. Median E. coli contamination on market tomato fruit samples (2.66 Log MPN/g) were higher (P < 0.001) than those from tomatoes collected on farms (0.92 Log MPN/g). Farmers and marketers were generally unaware of the relationship between food safety practices and microbial contamination on fresh produce. Good agricultural practices pertaining to food safety on farms and in local markets were seldom used. Adoption of food safety practices on-farm, during transport, and during marketing could improve the microbial quality of tomatoes available to the public in this region of the world.
authors.affiliation: Food Animal Health Research Program, The Ohio State University OARDC, 1680 Madison Avenue, Wooster, Ohio 44691, USA; Departments of Crop Protection, Ahmadu Bello University, Zaria, KD 810001, Nigeria.
authors.forename: Kenneth C
authors.initials: KC
authors.lastname: Shenge
authors.affiliation: Microbiology, Ahmadu Bello University, Zaria, KD 810001, Nigeria.
authors.forename: Clement M Z
authors.initials: CM
authors.lastname: Whong
authors.affiliation: Agricultural Economics, Ahmadu Bello University, Zaria, KD 810001, Nigeria.
authors.forename: Lydia L
authors.initials: LL
authors.lastname: Yakubu
authors.affiliation: Agricultural Economics, Ahmadu Bello University, Zaria, KD 810001, Nigeria.
authors.forename: Raphael A
authors.initials: RA
authors.lastname: Omolehin
authors.affiliation: International Programs in Agriculture Office, The Ohio State University, 2120 Fyffe Road, Columbus, Ohio 43210, USA.
authors.forename: J Mark
authors.initials: JM
authors.lastname: Erbaugh
authors.affiliation: Department of Plant Pathology, The Ohio State University OARDC, 1680 Madison Avenue, Wooster, Ohio 44691, USA.
authors.forename: Sally A
authors.initials: SA
authors.lastname: Miller
authors.affiliation: Food Animal Health Research Program, The Ohio State University OARDC, 1680 Madison Avenue, Wooster, Ohio 44691, USA. lejeune.3@osu.edu.
authors.forename: Jeffrey T
authors.initials: JT
authors.lastname: LeJeune
mesh_terms: D057914:Agricultural Irrigation; D000383:Agriculture; D000818:Animals; D003132:Commerce; D004755:Enterobacteriaceae / Q000254:growth & development; D004926:Escherichia coli / Q000254:growth & development*; D005243:Feces / Q000382:microbiology*; D005516:Food Microbiology; D059022:Food Safety; D006235:Hand Disinfection; D006801:Humans; D018551:Solanum lycopersicum / Q000382:microbiology*; D008372:Manure / Q000382:microbiology; D009549:Nigeria; D014871:Water Microbiology
chemical_list: D008372:Manure