Effect of Charcoal on Microbial Flora of Blended Vigna unguiculata

Bacterial colony count was carried out to ascertain the efficacy of charcoal as a preservative of Vigna unguiculata (Beans) paste. Microbiological analysis of bacteria associated with spoilage of the paste was done. The paste was homogenized and serially diluted. Spread plate method was used to inoculate, and isolate the bacteria. The microorganisms were incubated at 37°C for 24 hours. Bacterial species isolated were; Bacillus cereus, Bacillus subtilis, Bacillus licheniformis, Bacillus lentus, Alkaligens spp, Bacillus alvae, Staphylococcus aureus. Isolation of Bacillus cereus and Staphylococcus aureus was particularly of interest, because they are associated with public health problem, particularly food poisoning. The same Bacterial species were isolated both in the presence and absence of charcoal. However, the bacterial colony count in the presence of charcoal was much less (6.0 x 10³ CFU/ml) at 5hrs, than when charcoal was not used (5.0 x 10⁴ CFU/ml).