Microbial Qualities of Vegetables, Water and Soils from Vegetable Gardens in Lagos State, Nigeria

Abstract

The presence of coliforms in vegetables, water and soil samples from gardens in Lagos State was assayed for. The vegetables sampled were cabbage, waterleaf, carrot, lettuce and cucumber collected from five sites representing five geograpical zones. The isolates obtained were cultured on MacConkey (MAC) agar, Sorbitol MacConkey agar, Eosine Methylene Blue (EMB) agar and Salmonella-Shigella (SSA) agar. They were identified using morphological, biochemical and Analytical Profile Index 20E and 20SA kit. Hemolytic activity of the isolates was assayed for using Blood agar. The aerobic plate counts of soil, water and vegetable samples ranges from 8.80 x 107 to 8.00 x 109 cfu/g, 3.90 x 109 to 6.15 x 109 cfu/ml, and 3.30 x 109 to 1.08 x 1010 cfu/g, respectively. Coliforms were the predominant bacteria isolated from the sites. The coliform counts of cabbage, waterleaf, carrot, lettuce and cucumber were5. 01 x 109cfu/g, 6.76 x 107cfu/g, 5.49 x 107cfu/g, 1.58 x 108cfu/g and 4.67 x 104cfu/g respectively. The fecal colifom population range was between 2.51 x 103 and 1.31 x 108 cfu/g, while Salmonella and Shigella species ranged from 1.38 x 102-3.09 x 104 cfu/g. Escherichia coli 0157: H7 was not isolated from any of the sites. The study showed that washed vegetableswere contaminated with high microbial load especially coliforms.