Purpose: This study determined the microbial quality of some leafy green vegetables from irrigated vegetable farms in selected urban areas of Accra, Ghana.
Methods: Two exotic (lettuce and cabbage) and four indigenous (Amaranthus sp., Solanum macrocarpon, Hibiscus sabdariffa, and Corchorus olitorius) leafy green vegetables (n=175) were collected in duplicate from 50 farms in 12 farming areas in urban areas of Accra, Ghana from March to December, 2016. The vegetables rinses (0.1M phosphate buffered saline) were inoculated onto tryptic soy agar, MacConkey agar, Enterococcus agar, and potato dextrose agar and resulting microbial colonies were enumerated. Presumptive Salmonella colonies were isolated using the FDA BAM protocol.
Results: Average total aerobic bacteria, yeast and mold, fecal coliform, and enterococcus counts on collected vegetables ranged from 8.20 to 9.65, 4.22 to 5.20, 3.96 to 5.02 and 2.71 to 3.13 log CFU/g, respectively. Exactly 143 vegetables from 48 farms tested positive for fecal coliforms and 136 vegetables from 48 farms tested positive for enterococcus. Seven vegetable samples tested positive for presumptive Salmonella. Farming area and vegetable type had significant influence (p≤0.05) on average aerobic bacteria and yeast and mold counts. Farming area and farm had a significant influence (p≤0.05) on fecal coliform and enterococus counts. Cabbages had the highest aerobic bacteria counts, whilst lettuce had the lowest. The indigenous vegetables were higher in yeast and mold counts than cabbage and lettuce. Amaranthus sp. and cabbage had the lowest fecal coliform counts.
Significance: The results of this study suggested that leafy green vegetables cultivated in urban areas of Ghana were associated with high microbial counts. Consumption of fresh leafy green vegetables without sanitizing or heat treatment should be discouraged.