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Abstract

This paper presents the antimicrobial activity of instant coffee, a prevalent beverage utilized by millions of people worldwide every day. Several studies have shown that instant coffee contains many useful bioactive compounds, the most important: caffeine, trigonelline, chlorogenic acid, ferulic acid, caffeic acid, nicotinic acid, and phenolic compounds which are responsible for the antimicrobial activity. In this study, six strains of resistant bacteria were selected as follows (Methicillin-resistant Staphylococcus aureus MRSA, S. aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumonia, and Acinetobacter baumannii). The antibiotic sensitivity test revealed that the most tested bacterial strain was utterly resistant to the selected antibiotic discs. The antimicrobial activity of instant coffee was evaluated at different concentrations (20, 40, 60, and 80 mg/ml) against tested multi-drug resistant bacteria (MDR) and the fungi (A. niger and A. flavus). The results of antibacterial effect of instant coffee showed that the inhibition zone ranged between (7.6±0.5 and 19.6±0.5 mm). While the minimum inhibitory concentration (MIC) ranged between (62.5 and 32.25 mg/ml) against tested bacteria. Moreover, the instant coffee significantly inhibited the mycelial growth of A. flavus and the spore germination of A. niger. Based on the results obtained in this research, several future studies can propose to evaluate the biological activity of coffee, such as the molecular effect of coffee bioactive compounds against human microbiome. In addition to various medical and industrial applications.