Abstract

Bacteriocins are antimicrobials produced mainly by lactic acid bacteria as well other genera, a property which can be exploited in food biopreservation. However, narrow spectrum of activity of these bacteriocins is a limitation for their use in different food systems. Various approaches are being pursued to increase their antimicrobial efficacy like use of increased dosage, use of highly purified form in combination with other preservative techniques such as HPP, ultrasonic waves, use of a combination of bacteriocins, etc. Bacteriocins from two producers namely Lactobacillus plantarum MTCC 1407 and Bacillus coagulans MTCC 492 were used in the present study. Partially purified form of bacteriocin produced by them was tested individually as well as in combination with antimicrobial activity in liquid medium against food spoilage agents, Gram positive organisms such as Streptococcus thermophilus, Leuconostoc mesenteroides, Micrococcus flavus and also Gram negative organisms such as Escherichia coli and Pseudomonas aeruginosa. They were all susceptible to antimicrobial action of these bacteriocins, 26 to 72% inhibition was recorded with turbidometric method of assessment of bacteriocin activity. However, bacteriocins when used in combination of 1:1 (v/v) did not result in increased inhibition.

Key words: Bacteriocins, synergy, Lactobacillus sp., Bacillus sp., food spoilage agents.