Bacterial and Heavy Metals Contaminations of Some Vegetables in Mali

Abstract

Fresh vegetables eaten raw can be agents of transmission of microbes and heavy metals. The frequency and variability of microbes and heavy metals on 96 vegetables from some large production sites in Mali were evaluated. These sites were Bamako, Kati, Baguineda, Samanko, Sikasso and Niono. Among all sites, lettuce, tomato and cucumber from Sikasso were the least contaminated, and the concentrations of total microflora, total and faecal coliforms and Staphylococcus aureus on lettuce were respectively 19.88 × 104 CFU/g; 0.85 × 104 CFU/g; 0.73 × 104 CFU/g and 0.48 × 104 CFU/g. The concentrations of microorganisms on tomato following the order of the previous line were respectively 12.48 × 104 CFU/g; 0.24 × 104 CFU/g; 0.00 CFU/g and 0.97 × 104 CFU/g. The contamination of cucumber, still following the same order were 51.15 × 104 CFU/g; 13.33 × 104 CFU/g; 4.24 × 104 CFU/g and 11.03 × 104 CFU/g.. Vegetables from Kati were the most contaminated and the concentrations of lettuce were 145.58.104 CFU/g for the total microflora; 56.36 ×104 CFU/g for total coliforms; 23.03 × 104 CFU/g for faecal coliforms, 27.88 × 104 CFU/g for Staphylococcus aureus, 0.87 × 104 for Clostridium perfringens and 31.15 × 104 for Listeria monocytogenes. The concentrations of tomato were respectively 85.33 × 104 CFU/g; 12.48 × 104 CFU/g; 9.58 × 104 CFU/g; 17.94 ×104 CFU/g; 0.24 × 104 and 18.67 × 104 CFU/g. And the concentrations of cucumber were 67.64 × 104 CFU/g; 13.70 × 104 CFU/g; 9.82 × 104 CFU/g; 0.61 × 104 CFU/g; 1.28 × 104 and 14.42 × 104 CFU/g, respectively. Among vegetables, lettuce was the most contaminated at all sites except Sikasso and Baguineda where cucumber was the most contaminated.