Comparative study of the antimicrobial activity between raw and powdered spices

Abstract

Currently, pathogen-led infectious diseases and food poisoning caused by microbial spoilage are some of the biggest concerns for human health all over the world. However, the efficiency level of some antimicrobial agents that inhibit disease-causing microorganisms has weakened over time. This has given rise to the need for discovering new antimicrobial agents that can lower the rate of harmful microorganisms in food and medicine. This study focuses on the commonly consumed spices and investigates their antimicrobial effect on various multidrug-resistant organisms. Furthermore, it focuses on comparing the effectiveness of raw and powdered spices. Four every day consumed spices (Turmeric, Ginger, Cinnamon, and Black Pepper) were tested against a total of eight organisms (ETEC, EIEC, Klebsiella pneumonia, Acinetobacter baumannii, Bacillus cereus, Staphylococcus aureus, Staphylococcus saprophyticus and Pseudomonas aeruginosa), following three different protocols (non-standardized disc diffusion, non-standardized well diffusion and standardized disc diffusion). On an overall observation, the only spice that showed antimicrobial activity in all 3 methods and against almost every bacteria, is Ginger. It is more effective in the non-standardized methods compared to the standardized methods. This led us to believe that abundance encourages effect for Ginger. Observations also concluded that powdered Ginger is effective in all methods whereas raw Ginger is not. The second most effective spice was Turmeric. However, it only showed antimicrobial activity in non-standardized disc diffusion. The highest zone of inhibition was found in Staphylococcus aureus (Raw = 21 mm, Powder = 26 mm). Cinnamon showed the weakest results across all 3 methods. Only in a few cases zones were observed in Bacillus cereus (21 mm) and Staphylococcus aureus (15 mm) for raw Cinnamon. On the other hand, powder Cinnamon showed inhibition for Bacillus cereus (20 mm), Staphylococcus aureus (15 mm), and ETEC (18 mm). To summarize the study according to our goal, powdered spices were more effective under various conditions in comparison to raw unprocessed spices. Ginger can be labeled as the most effective antimicrobial spice.