Abstract

Tomato fruit undergoes rapid deterioration due to microbial spoilage caused mainly by fungi. The aim of this work is to determine the inhibitory effect of Lactobacillus plantarum and Lactobacillus fermentum against spoilage fungi of tomato fruit Lactobacillus plantarum and Lactobacillus fermentum were isolated from five different yoghurt samples and three different ogi samples by plating on MRS agar plates. Spoilage fungi of tomato were isolated on PDA and were identified as Aspergillus niger, Rhizopus stolonifer and Mucor sp. using their colonial morphology and microscopic characteristics. The antifungal activity of Lactobacillus plantarum and Lactobacillus fermentum against the isolated spoilage fungi of tomato was determined using the agar well diffusion technique. The result showed that after 24h of incubation, Aspergillus niger was inhibited by Lactobacillus plantarum with zone of inhibition of 2mm while Lactobacillus fermentum showed a higher inhibition of 4mm. Rhizopus stolonifer was only inhibited by Lactobacillus plantarum with a zone of inhibition of 2mm and Mucor sp. was also inhibited by Lactobacillus plantarum with zone of inhibition of 1mm. The antifungal activity exhibited by Lactobacillus plantarum and Lactobacillus fermentum showed that they are highly effective against eliminating spoilage fungi of tomato. However, further studies should be conducted to determine the metabolite responsible for the antifungal activity and methods designed so that they can be used as aerosols or used in modified atmosphere packaging of tomato so as to increase the shelf life of tomatoes. Keywords: antifungal, lactic acid bacteria, spoilage fungi, tomato fruit.