Research ArticleOpen Access

Detection of Escherichia Coli in Freshly Harvested Spinach Samples Collected from Five different markets in Zaria

Karaye GP1*, Karaye KK2, and Kaze PD1

1Department of Veterinary Parasitology and Entomology, University of Jos, Jos, PMB 2084, Plateau State, Nigeria.
2Central Diagnostic Laboratory, National Veterinary Research Institute, Vom Plateau State, Nigeria.

*Corresponding Author: 
Karaye GP
  Department of Veterinary Parasitology and Entomology
  University of Jos, Jos, PMB 2084
  Plateau State, Nigeria.
  Ph: +2348060926642
  E-mail: [email protected]

Citation: Karaye GP, Karaye KK and Kaze PD (2019) Detection of Escherichia Coli in Freshly Harvested Spinach Samples Collected from Five different markets in Zaria. J Microbes Microbio Techni 2(1): 101


Escherichia coli, though, normal flora of the digestive tract of human and animals have over the years evolved the ability to cause a wide range of disease. A total of 100 freshly harvested and ready to sale spinach samples in five selected market in Zaria, Kaduna State were collected and analysed for E.coli 0157:H7. Twenty (20) samples each were collected from Sabon Gari, Palladan, Samaru, Hayin Dogo and PZ. Isolates were screened using the conventional biochemical characterization for E. coli O157: H7. Twelve (12) gram of spinach leaves each was washed with sterile distilled water. Five (5) mls of each washing was inoculated into 5 mls of double strength MacConkey broth and inoculated for 24 hours at 370C. A loop full of the positive colonies was sub cultured on EMB Agar and incubated for 24 hrs at 370C a greenish metallic sheen on the surrounding medium were observed. These presumptive positive colonies were stored in nutrient Agar slant at 40C until it was required for biochemical test. E.coli was confirmed by biochemical test and the growth on EMB Agar. Out of the 100 samples collected, Isolates were screened using the conventional biochemical characterization for E. coli O157: H7. A total of 119 (47.6%) E. coli O157: H7 and 16 (6.4%) E. coli O157 was isolated respectively. Therefore, there is need to characterize the E.coli from spinach in local markets in Zaria, so as to checkmate and create awareness on the spread of E.coli especially 0157:H7 infection in livestock and humans in Zaria and Kaduna State.

Keywords: Escherichia Coli; Spinach; Zaria; Biochemical test; EMB Agar


Escherichia coli are natural predominant facultative anaerobes common in the lower intestines of endothermic animals and it grows in most laboratory media at an incubation temperature of (37℃) optimum (Feng et al., 2011). They colonize the gastro intestinal tract hours after birth or days after (Lans et al., 2002). Nevertheless, some strains have evolved the capability to cause both intestinal and extra intestinal illnesses (Nataro et al., 2011; Quinn et al., 2011). Not all the strains are harmless, as some can cause debilitating and sometimes fatal diseases in humans as well as mammals and birds (Belanger et al., 2012). Faecal–oral transmission is the major route through which pathogenic strains of the bacterium cause disease. Cells of the bacteria can survive outside the body for a limited amount of time, which makes them potential indicator organisms to test environmental samples for faecal contamination. (Feng, 2002; Thompson et al., 2007 ). In Zaria, Tijani et al., (2006); Kabiru et al., (2015) reported the prevalence of Escherichia coli 0157:H7 in spinach grown around abattoir waste dumpsite, manure farm and soil, irrigated with raw abattoir waste water. This suggests that spinach are vegetables that can potentially harbor Escherichia coli when manured with contaminated faeces. The use of raw manure or slurry (liquid manure) on or near fruit and vegetable crops, particularly those to be eaten raw is a potential hazard for Escherichia coli especially 0157:H7 (Tijani et al., 2006) and hence the need for work to be done on the prevalence of E.coli in spinach meant for human consumption in Zaria and its environs. Studies have shown that Escherichia coli especially 0157:H7 can survive in faeces for extensive periods of 70-100 days at the temperature in the region of 45℃, (Dahiru et al., 2008). Thereby establishing that faeces serving as manure to most subsistence and commercial farmers growing spinach at backyard or irrigational farms at dry season may be a potential vehicle for transmission of the organism into the environment (Wang et al., 1999).

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