Microbiological Quality Of Organic Vegetables Cultivated In Soils Treated With Organic Manure

ABSTRACT

Microbiological quality of vegetables cultivated in soils treated with poultry manure was determined. Four vegetables: waterleaf, pumpkin, cucumber, and tomatoes were used. Samples were examined for microbial contamination and bacterial isolates: Escherichia coli, Staphylococcus aureus, Klebsiella spp., Bacillus subtilis, Salmonella spp. and Shigella spp. were recovered from the soils and vegetables. The total bacterial count of the soil samples ranged from 75x10cfu/ml (S3) to 5.9x10cfu/ml (S4) while the total bacterial count for the vegetable samples ranged from 2.65x 10cfu/ml (P) to 1.50x10°cfu/ml (W). The total coliform count of the experimental soil samples ranged from 1.65x 10'cfu/ml (S3) to 6.9x10cfu/ml (S4) while that of vegetable samples ranged from 1.20x10cfu/ml (P) to 7.2x10cfu/ml (W). S1 was significantly different from S2 and S4 for the total bacteria count for the soil samples while P and W were significantly different for the vegetable samples (P< 0.05). For Salmonella-Shigella plate counts, SI and S4 were significantly different and S2 and S3 were same (P< 0.05); while the vegetable samples, P, W, C and T were significantly different (P< 0.05). S 1, S2, S3, and were significantly different for the total coliform count for the soil samples and same for P, W and C (P<0.05). Sensitivity screening for the isolates showed that Bacillus subtillis was most sensitive to Ofloxacin (25mm) while Staphylococcus aureus was most sensitive to Ofloxacin (22mm). Shigel/a was most sensitive to Ciprofloxacin (25mm) while E. coli showed highest sensitivity to Ciproflacin (25mm) and Ofloxacin (25mm). In addition, Klebsiella was most sensitive to Ciprofloxacin (23mm) and Ofloxacin (23mm) and Salmonella showed resistance to the antibiotics. This study demonstrated that there is a high level of microbial contamination associated with the cultivation of vegetables in soils in which organic manure has been applied to which is of risk to the consumers