Antimicrobial Effects of Herb Extracts and Their Applications in Edible Films

Abstract

Crude extracts from dried fingerroot, garlic, cloves and cinnamon were studied for their antimicrobial activity against Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus and Pseudomonas aeruginosa. Extract from cinnamon showed the highest activity with minimum inhibitory concentration (MIC) ranging from 31.25 to 100 mg/ml, followed by extracts from cloves and fingerroot with MICs of 100-250 and 200-500 mg/ml, respectively. Garlic extract showed no inhibitory effect against these bacteria. The inhibitory activity of the extracts decreased over the storage period of 8 weeks at 4°C. However, cinnamon and cloves extracts still possessed considerable inhibitory activity with slightly higher MICs of 100-250 and 200-500 mg/ml, respectively. Carrageenan films incorporated with cinnamon and cloves extracts of one five and ten times their MICs were tested for their antimicrobial effects against the test microorganisms and those taken from dried salted fish, called cocktail microorganisms. Higher concentrations than their MICs were observed and cinnamon extract gave better results than cloves extract. The inhibitory effects were promising against cocktail microorganisms, evidenced by the fact that neither bacterial nor yeast and mold growth was shown with cinnamon extract of five times and at their MICs, respectively. Additionally, cloves extract could inhibit the growth of cocktail yeast and mold at its MIC.