Antimicrobial activity of coconut shell liquid smoke

Coconut shell liquid smoke is produced from the pyrolysis and condensation of smoke from the burning process of coconut shell. It is known to have considerably high content of polyphenol. Beside acting as antioxidant, polyphenol is also a good antimicrobial. This research was conducted in order to study the antimicrobial activity of coconut shell liquid smoke. Coconut shell liquid smoke used in this study was produced from three different processing stages, which obtained three different grades of liquid smoke (grade 1, 2 and 3). Each sample of coconut shell liquid smoke was extracted using ethyl alcohol and petroleum ether. The extract was then analyzed for its antimicrobial activity against S. aereus, E. coli and C. albicans using well diffusion method. Total phenol and microbial microscopic structure of the liquid smoke were also examined. The results showed that there was influence of coconut shell liquid smoke on the inhibition of S. aureus, E. coli and C. albican growth. This fact was marked by the forming of clear area surrounding the well on the dish agar media. The highest percentage of inhibition showed by the extract of grade 3 coconut shell liquid smoke. This may be explained by the highest total phenol content in grade 3 liquid smoke. Microscopic examination showed that there was a breakage of microbial cell walls caused by the antimicrobial property of the liquid smoke. It was concluded that coconut shell liquid smoke was beneficial as antimicrobial agent, and while all grades of liquid smoke contains polyphenol, the content was influenced by the processing stage and thus influenced its level of microbial growth inhibition.