Antimicrobial activities of phenolic extracts of coffee mucilage

The inhibition exerted by ethanolic extracts of coffee mucilage on the growth of bacteria was studied by microdilution in agar. The growth inhibition effect was evaluated for pathogenic or food spoilage related bacteria (Pseudomonas aeruginosa (ATCC 27853), Alcaligenes sp. (UCR277), Serratia sp. (UCR299), Micrococcus luteus (ATCC4698), Escherichia coli (ATCC35150), Staphylococcus aureus (ATCC25923), Bacillus cereus (ATCC14579), Salmonella enterica subsp. enterica (ATCC 13311) and Listeria monocytogenes (SLCC4013)) and for bacteria associated with human intestinal biota (Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus rhamnosus, Lactiplantibacillus plantarum subsp. plantarum). The most effective growth inhibition was observed for B. cereus (ATCC14579). The content of chlorogenic acid and caffeine in the ethanolic extracts was quantified by HPLC/ DAD. The chlorogenic acid content in the extracts ranged from 2.67 to 4.76 mg/ml, while the caffeine content ranged from 1.24 to 6.48 mg/ml. Although ethanolic extracts of coffee berry mucilage inhibited the growth of B. cereus, this inhibition does not seem to be related to the caffeine or chlorogenic acid contents.