Antibacterial Activity and Phytochemical Screening of Turmeric Extracts on Bacteria Associated With Spoilage of Prepared Tomato Concentrate

Abstract

Food substances can be classified as either perishable or non-perishable, with tomatoes being one of the most common perishable items. The preservation of perishable foods is essential for extending their shelf life, maintaining quality, and preventing spoilage. Bacteria were isolated from stored tomato concentrate, characterized and identified. Antibacterial screening of methanolic, n-hexane and aqueous extracts of the turmeric was done using the agar-well diffusion method. The qualitative phytochemical contents of the extracts were assessed using standard methods. Isolates were identified as Staphylococcus sp., Bacillus sp., Streptococcus sp., Clostridium sp., and Lactobacillus sp. The n-hexane extract was significantly effective against two of the test bacteria with zones of inhibition of 15.00 and 16.00 mm against Staphylococcus sp. and Clostridium sp. respectively at a concentration of 128 µg/ml. Similarly, the methanolic extract inhibited the growth of Staphylococcus sp. and Streptococcus sp., with zones of 14.00 and 19.00 mm respectively at 128 µg/ml. The MIC values ranged between 625 µg/ml and 1 mg/ml, while MBC values were generally higher, between 1 mg/ml and 2 mg/ml, indicating a concentration-dependent antibacterial effect. The phytochemical analysis revealed the presence of terpenoids, alkaloids, flavonoids, and steroids, which may contribute to the observed antibacterial activities. These findings suggest that turmeric extracts are effective against spoilage bacteria and could potentially be used to prevent the spoilage of tomato concentrate.