Antibacterial activity of several Malaysian leaves extracts on the spoilage bacteria of yellow alkaline noodles

Abstract

Yellow alkaline noodle (YAN) is very susceptible to spoilage and has ashort shelf life due to the high moisture content. This study wasconducted to isolate and identify spoilage bacteria of YAN in an attemptto apply local plant extracts that possess antibacterial activity inextending the shelf life of YAN. Thirty colonies were isolated fromspoiled YAN and were identified using the Biolog GEN III system. Eightbacteria which consisted of five Gram-positive (GP) and threeGram-negative (GN) (Bacillus pumilus, Clavibacter agropyri,Corynebacterium urealyticum, Corynebacterium jeikeium, Enterobactercloaceae, Pseudomonas aeruginosa, Serratia marcescens and Staphylococcussciuri) were identified. E. cloaceae and S. sciuri were the mostabundant bacteria on YAN with percentage values of 23 and 26%,respectively. The antibacterial activities of ethanol and water extractsof six types of leaves (Centella asiatica, Jasminum sambac, Pereskiableo, Cosmos caudatus caudatus, Murraya koenigii, and Melicope lunu)against all the identified bacteria were studied. The ethanol extractsof M. koenigii are most effective extract that possess the highestantibacterial activity against all the eight spoilage bacteria studied.