Microbiological Evaluation of Locally Processed Herbal Drugs Sold in Benin City

Plants that are referred to as “herbs” are not used as a food, but are grown and consumed as a garnishment for flavour enhancement, seasoning, and sometimes for alleged healing properties. This study investigates the microbiological quality of common herbal drugs sold in Benin City and antibacterial susceptibility profile of the Isolates. Herbal concoctions were purchased from various traditional medicine sales outlet in Benin City, Nigeria, coded as HA to HJ. Bacterial were cultured on Nutrients Agar while fungi were cultured on Potato Dextrose Agar. The highest bacterial count was 2.90 ± 0.20×104 cfu/mL (HB and HH) while the lowest was 9.50± 0.20 × 103 cfu/mL (HF). The fungal counts of herbal concoction samples analysed were found to have the highest value of 1.80± 0.20 ×104 cfu/mL (HF) and least 6.00± 0.0 ×103cfu/mL (HI). The identified bacterial isolated from the herbal concoctions were Bacillus licheniformis, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Staphylococcus epidermidis. The fungal isolates included Penicillium sp, Aspergillus flavus, Aspergillus niger and Rhizopus sp. Pseudomonas aeruginosa had the highest resistance to all tested antibiotics while the most sensitive isolates were Bacillus licheniformis and Staphylococcus epidermidis. Bacterial count in the herbal preparations were below the stated acceptable limit, but their presence represents a potential risk of infectious diseases. Therefore, appropriate standards in herbal medicinal preparations and all medicinal plants should be adhered to in order to reduce the risks of infections to consumers in Nigeria.