In-Viro Inhibitory Effects Of Bacteriocin From Lactic Acid Bacteria Against Food Spoilage Organism:- Nwagiri, Prince C

ABSTRACT ix Bacteriocin was discovered more than a century ago (Basseet al., 2015) as heterogeneous ribosomally synthesized proteinaceous molecules with strong antibiotic activity at precise concentrations (Chikindase/ al., 2018). They are generally defined as peptides or proteins ribosomal synthesized by bacteria that inhibit or kill other related or unrelated microorganisms (Leroy and De Vuyst, 2004; Cotter et al., 2015). The work studied the in-vitro inhibitory effect of bacteriocin of Lactic Acid Bacteria (LAB) from ugba against spoilage bacteria of carrot (Daucus carrota). Seven bacteria species were isolated from randomly selected spoilt carrot tubers from the local daily market at Ahiaeke Ndueme, Umuahia North LGA, Abia State. The isolates and their respective occurrences include Staphylococcus aureus (100%), Bacillus sp. (80%), Pseudomonas sp. (60%), Enterobacter (20%), Escherichia coli (40%), Shigella (20%) and Campylobacter (40%). Four Lactic Acid Bacteria (LAB) which include Lactobacillus plantarum, Lactobacillus fermentum, Leuconostoc sp. and Streptococcus sp. were isolated from ugba and their crude bacteriocin extracts were used for tests. Result ofpathogenecity tests showed that four ofthe seven bacteria isolates which include Enterobacter, Bacillus, Campylobacter and Pseudomonas effected rot in the healthy carrots and were adjudged to be pathogenic. Campylobacter was the most pathogenic causing a main rot of 54.37% while Bacillus had the least pathogenecity of 43.4% rot. Pseudomonas and Enterobacter had 53.23% and 51.16% rots respectively. The potentials ofthe crude bacteriocin extracts from Lactic Acid Bacteria controlling spoilage bacteria was observed notwithstanding their lower entity relative to standard antibiotic. It was concluded, from the obtained results oftests and analysis in the project work, that spoilt carrot is inhibited by many different bacteria species some of which may cause diseases. Also, not all the harbored bacterial isolates ofspoilt carrot could cause disease to healthy carrot thus leading to the suspicious that some then be transient in the vegetable.