Microbes in Irrigation Water and Fresh Vegetables

Abstract

Irrigated fresh vegetables are a potential portal for dissemination of human pathogens that may be associated with irrigation water source. This study investigated the quality of irrigation water and the fresh vegetables produced in regard to pathogenic bacteria found at a selected vegetable farm in southwestern Nigeria. Enumeration and characterization of total heterotrophic bacteria and potential pathogens (mostly enteric bacteria) were done with international procedures. Susceptibility of the potential pathogens to antibiotics was by disk diffusion techniques, while plasmid profile was by polymerase chain reaction-based DNA fingerprinting. The mean values for total heterotrophic bacteria in irrigation water and fresh vegetable samples were, however, statistically comparable (P ¼ .86). The corresponding comparison for coliform also showed no significant difference (P ¼ .07). The isolated pathogenic bacteria genera from the irrigation water and fresh vegetable samples include Citrobacter, Enterobacter, Escherichia, Klebsiella, Pseudomonas, and Salmonella. In sum, 67.2% of the isolates were obtained from irrigation water samples, compared with 32.8% in the vegetable samples; 54.1% of the isolates were resistant to >1 antibiotic with a multiple antibiotic resistance index >0.2, suggesting an antibiotic pressurized environment. Resistance to ampicillin was very high (98.36%), whereas resistance to ciprofloxacin was very low (0.0%); 27.9% of the multiresistant enteric isolates harbored !1 plasmids. There is a possibility of increased numbers of pathogens on irrigated vegetables as a direct consequence of poor irrigation water quality in the study site. The use of pathogen-free irrigation water and good agricultural practices has the potential to eliminate microbial hazards in fresh vegetables.

Contamination Alert: Microbial and Heavy Metal Levels in Green Vegetables

“…As for the bacteria of the genus Klebsiella, their very sticky pink colonies appeared fermenting the sugar lactose on the MacConkey medium, and as for the E.M.B medium, they appeared in a slightly pinkish-orange color. This is consistent with the results of the study [19]. In microbial examination, the isolates were examined in the optical microscope, the results were all Gram-negative bacteria, rod-shaped and short, as shown in Figure .…”

Evaluation of the Effect of Wastewater Irrigation on the Microbiological Quality of Vegetables in Northeast Ethiopia: Implication for Food-Borne Infection and Intoxications

“…The mean TBC of the irrigation water sample in the present study was 4.2 log CFU/mL. Higher results (5.5 and 7.1 log CFU/mL) were reported in Ibadan, Nigeria, 41 and Hawassa, Ethiopia 9 respectively. The TC level of 3.9 log CFU/mL in the present study is slightly lower than the study reported by Akinde et al, 41 where the mean TC in the irrigation water sample was found to be 4.1 log CFU/mL.…”

“…Higher results (5.5 and 7.1 log CFU/mL) were reported in Ibadan, Nigeria, 41 and Hawassa, Ethiopia 9 respectively. The TC level of 3.9 log CFU/mL in the present study is slightly lower than the study reported by Akinde et al, 41 where the mean TC in the irrigation water sample was found to be 4.1 log CFU/mL. Zavadil 11 also reported higher TC and FC (6.2 and 5.4 log CFU/mL, respectively) values from the irrigation wastewater.…”

“…Muinde and Kuria 43 also agreed that wastewater from the bathroom, kitchen, and laundry used in the cultivation of these vegetables is the most common source of bacterial contamination. In addition, Akinde et al 41 indicated that microbial contamination of vegetables occurs throughout the life cycle, from cultivation to consumption, including the irrigation water sources. 3,42…”

Preharvest Transmission Routes of Fresh Produce Associated Bacterial Pathogens with Outbreak Potentials: A Review

“…Irrigation is the application of water to the soil during agricultural production of farm produce to maximize the yield of fresh produce, and this is especially done during the dry seasons [90]. Irrigation water is used to supplement inadequate rainfall in many regions of the world, and being a critical requirement for the optimum production of farm produce, it is necessary to irrigate plants whenever needed [91].…”