COMPARATIVE STUDIES OF ANTIBACTERIAL POTENTIAL OF BLACK PEPPER, GARLIC AND GINGER ON FOOD SPOILAGE BACTERIA

ABSTRACT Microorganisms that are used to spoil food also present considerable economic and health hazards to all populations as they impair quality and safety of food products. This paper compared the comparative antibacterial effect of extracts of ginger (Zingiberofficinale), garlic (Allium sativum) and black pepper (Piper nigrum) against a collection of food spoilage pathogens using agar well diffusion method. Zones of inhibition were also generated by using garlic ethanolic extracts which had a range of 10 to 13mm against Micrococcus spp., Streptococcus spp. and Proteus mirabilis at a concentration of 50mg/ml with a minimum inhibitory concentration (MIC) of 40-45mg/ml. Garlic aqueous extracts were found to be inhibitory in Bacillus subtilis, Pseudomonas aeruginosa, Mirococcusspp, and Staphylococcus epidermidis at the same levels of MIC. Ginger ethanolic extracts showed moderate inhibitory effects against staphylococcus spp. and P. mirabilis with MIC of 40 mg/ml but black pepper extracts did not show any inhibitory effects on any of the test isolates. Phytochemical analysis was done to yield presence of terpenoids, flavonoids and saponins in some samples. In general, ginger and garlic show promise as natural preservatives, however, they still need to be refined in order to improve bactericidal activity and secure countermeasures to resistance in food systems.