Efficacy of Bacteriocin Producing Lactic Acid Bacteria Isolated from Ugba and Okpiye Against some Selected Bacterial Food Spoilage Agents

Abstract

Numerous food products owe their production and characteristics to the fermentative activities of microorganisms. Bacteriocins are antimicrobial proteins produced by bacteria that kill or inhibit the growth of other related species. Lactic acid producing bacteria were isolated from Ugba and Okpiye using standard methods. The test organisms used were Staphylococcus aureus, Pseudomonas aeruginosa (VRFPA04) and Escherichia coli (ST2747) Fifty (50) samples of Ugba and Okpiye were collected and evaluated for the presence of bacteriocin lactic acid producers using a selective medium; De Mann Rogosa Sharpe (MRS) agar. A total of 288 isolates was isolated from the two traditional food condiments; 148 from ugba and 140 from Okpiye. It was observed that the total lactic acid bacterial count in Ugba ranges from 5.80 x 104 to 1.7 x 107 cfu/ml on MRS medium; while that of Okpiye ranges from 5.0 x 104 to 2.0 x 107 cfu/ml on MRS medium. Lactic acid bacterial count was higher in Ugba than in Okpiye
considering the mode of storage in the market. The highest inhibitory activity was demonstrated against E. coli in Ugba sample while the least activity was demonstrated against P. aeuroginosa, also a significant high level of inhibition was shown against S. aureus while P. aeuroginosa and E. coli had little or no inhibitory activities recorded for Okpiye samples. The bacteriocin producers isolated from Ugba and Okpiye (U5, U6, OK1, OK2, OK3 and OK4) were identified as Lactobacillus sp and Lactococcus sp based on their morphological and biochemical characteristics. The antibacterial activity of the bacteriocins produced by the lactic acid bacteria has potential for use in biopreservation of condiments against food spoilage agents.