ABSTRACT
Tropical fruit and vegetable wastes become great potential natural resources of bioactive compounds for antimicrobial. The aim of the study was to determine the effect of antimicrobial extracted from tropical fruit and vegetable waste to inhibit foodborne pathogenic bacteria (Aeromonas hydrophilla, Bacillus cereus, Escherichia coli, Listeria monocytogenes, Salmonella Typhimurium, Staphylococcus aureus, Vibrio parahaemolyticus). A total of six tropical fruit waste (peel of pineapple, jackfruit, durian, coffee, mangosteen, and cacao pods) and five tropical vegetable waste (stem of sembukan, lamtoro pods, jengkol shell, bitter bean pods, Indian marsh fleabane leave) was extracted by using maceration method. The antimicrobial activity of extracts was carried out by using disc diffusion assay and Minimum Inhibitory Concentration. The flavonoids in extract were identified and quantified by using Liquid Chromatography-Mass Spectrometry. The highest antimicrobial activity against Gram-positive bacteria (B. cereus, L. monocytogenes and S. aureus) was shown by jengkol, bitter bean and mangosteen waste extract in the range of 0,00038 to 4,2% for MIC. The highest antimicrobial activity inhibits Gram-negative bacteria (A. hydrophilla, E. coli, S. Typhimurium and V. parahaemolyticus) was shown by jengkol, bitter bean, mangosteen, sembukan and lamtoro waste extract in the range of 0,00038 to 3,1% for MIC which have apigenin, catechin, coumaric acid, gallic acid, genistein, hydroxybenzoic acids, luteolin, myricetin, naringenin dan quercetin as bioactive compounds. Total phenol of those waste extracts was in the range of 0.663 to 4,441 mg GAE/g. Jengkol, bitter bean, mangosteen, sembukan and lamtoro waste extract shown to be a potential natural antimicrobial to inhibit food-borne pathogenic bacteria.
ABSTRACT
A total of 43 Salmonella enterica isolates belonging to different serovars (Salmonella Albany, Salmonella Agona, Salmonella Corvallis, Salmonella Stanley, Salmonella Typhimurium, Salmonella Mikawasima, and Salmonella Bovismorbificans) were isolated from catfish (Clarias gariepinus) and tilapia (Tilapia mossambica) obtained from nine wet markets and eight ponds in Penang, Malaysia. Thirteen, 19, and 11 isolates were isolated from 9 of 32 catfish, 14 of 32 tilapia, and 11 of 44 water samples, respectively. Fish reared in ponds were fed chicken offal, spoiled eggs, and commercial fish feed. The genetic relatedness of these Salmonella isolates was determined by random amplified polymorphic DNA PCR (RAPD-PCR) using primer OPC2, repetitive extragenic palindromic PCR (REP-PCR), and pulsed-field gel electrophoresis (PFGE). Composite analysis of the RAPD-PCR, REP-PCR, and PFGE results showed that the Salmonella serovars could be differentiated into six clusters and 15 singletons. RAPD-PCR differentiated the Salmonella isolates into 11 clusters and 10 singletons, while REP-PCR differentiated them into 4 clusters and 1 singleton. PFGE differentiated the Salmonella isolates into seven clusters and seven singletons. The close genetic relationship of Salmonella isolates from catfish or tilapia obtained from different ponds, irrespective of the type of feed given, may be caused by several factors, such as the quality of the water, density of fish, and size of ponds.
