ABSTRACT

Tomato (Solanum lycopersicum), a plant of the nightshade family (Solanaceae) is cultivated extensively for its edible fruits. It is labelled as a vegetable for nutritional purposes. Tomatoes are a good source of vitamin C and the phytochemical lycopene. Ripe tomato fruits can stay for 3-5 days before spoilage, therefore, the need to investigate local method of preservation to increase the shelf life. The present study was aimed at investigating the antibacterial activity of some plant extracts, including Azadirachta indica (neem), Allium sativum (garlic) and Zingiber officinale (ginger) against pathogenic bacteria isolated from diseased tomato fruits. Cultural and biochemical tests, which included gram staining, catalase test, and citrate test were used to identify the bacterial isolates. The antibacterial activity of the various leaf extracts was tested against the isolated pathogenic bacteria using the agar well diffusion technique. The results of the cultural and biochemical tests showed that the bacterial isolates from the diseased tomato included species of Bacillus sp and Micrococcus luteus. The highest level of zone of inhibition in the antimicrobial sensitivity test was observed in the 80 g/l of garlic extract. Meanwhile, there was no zone of inhibition in the other treatments. The findings of this study suggest that aqueous extract of 80 g/l of Garlic (Allium sativum) had antibacterial activity and may be explored in the preservation of tomatoes.