In-vitro antibacterial activity of garlic cloves and ginger rhizomes on food-borne pathogens

The antibacterial activity of ginger (Zingiber officinale) and garlic (Allium sativum) extracts was investigated on selected food borne pathogens using Agar well diffusion method. The organisms are Escherichia coli, Staphylococcus aureus, Salmonella species and Bacillus cereus. Two different extracts (cold water and ethanol) were obtained from the garlic bulbs and ginger rhizomes. The results indicated that the different bacteria species demonstrated different levels of sensitivity to the extracts. The cold water extract of the ginger produced maximum activity against Salmonella species (13.10mm), Staphylococcus aureus (9.67mm), Bacillus cereus (6.67mm) and no inhibition on Escherichia coli (0.0mm). The ethanolic extract produced maximum activity against Staphylococcus aureus (13.05mm), Salmonella species (10.09mm) and no inhibition on Escherichia coli (0.0mm) and Bacillus cereus (0.0mm). The extracts of garlic (cold water and ethanolic) produced the maximum inhibitory effect towards Staphylococcus aureus (38.67mm and 31.00mm), Bacillus cereus (36.67mm and 30.21mm) respectively. The cold water extract produced an inhibition of 26.00mm on E. coli and 27.33mm on Salmonella species while the ethanolic extract on E. coli (20.10mm) and Salmonella species (19.32mm). The minimum inhibitory concentration (MIC) of cold water and ethanol extracts of ginger were respectively 75% and 50% (S. aureus), 50% and 25% (Salmonella species), 100% and resistant (B. cereus) while E. coli was resistant to both extracts. The MIC (%) of the cold water and ethanol extract of garlic were respectively 25% and 75% (B. cereus), 25% and 50% (S. aureus) and 75% for both extracts on E. coli and Salmonella species respectively. The result revealed that garlic extracts were more effective against the test organisms than ginger extracts. However both plants can serve as potential inhibitors of food pathogens and can increase the shelf life of foods if properly incorporated.