Effect of Blanching and Oil Marination on Bacteriological Quality of Tomato

Abstract

Tomato has suffered a great yield loss owing to microbial contaminations, especially fungi and bacteria. This study was carried out to know the effect of blanching and oil marination on the total bacterial count and isolates present in tomato. Fresh tomato samples were collected from Kasuwan Daji, Sokoto state. The tomato was divided into three groups; two groups were processed into blanched and un-blanched marinated into oil. The bacteria analyses of both the fresh and preserved stored samples were carried out at day 1 for fresh and after 2 days interval for preserved tomatoes for a period of 14 days. The bacterial load of the fresh sample was 5.06 ± 0.900Log10cfu/g and that of the blanched sample ranges from 4.63 ± 0.702 to 5.31 ± 0.915 Log10cfu/g while that of the un-blanched sample ranges from 5.31 ± 0.950 to 5.66 ± 0.960 Log10cfu/g. There is no significant difference in the total bacterial load of both the blanched and un-blanched samples with that of the fresh P>0.05, but load increases with time while the bacterial load of the un-blanched sample is higher compared to the fresh and also increases with time. The pH value of the blanched sample over the 14 days ranges from 7.00 to 6.52 while that of the un-blanched sample ranges from 6.90 to 5.92. A total of three bacteria were isolated from the samples, they are Bacillus lacterosporus, Listeria monocytogenes and Staphylococcus hominis. Bacillus lacterosporus and Listeria monocytogenes were isolated from the fresh sample, Listeria monocytogenes was isolated from the blanched sample while Staphylococcus hominis and Bacillus lacterosporus were isolated from the un-blanched sample. Blanching is effective in reducing microbial load and increase the shelf life of tomato coupled with oil marination.