Isolation and identification of Bacillus stearothermophilus and study the inhibition effect of squeezed grape waste extract on it.

Abstract

The aim of this study was to know the inhibition activity of squeezed grape waste extract on Bacillus stearpthermophilus by using three different tempretures degree 40, 60 and 80c, in order to reduce the time exposure of food for preservation. This study include two branchs: First: isolation and identification of Bacillus stearothermophilus from soil, 5 sample were collected from the soil of the college agriculture/Baghdad university. Samples were cultured on nutrient agar, microscopic and culturing tests were conducted and many biochemical tests were done. The isolates were cultivated at 55 c and 65 c for differentiate it from Bacillus coagulans which is can^'t grow at 65 c^o. The choosed isolate was identified as B. stearothermophilus which is bacilli, spore forming, g+ve ,motile and with 0.71-3 µm diameter. Second studying the inhibition activity of squeezed grape waste extract against isolated bacteria (in vitro) by using different temp mentioned above at differenttimes(0, 10, 30, 40 and 50) min with 500 ppm conc. Of the extract. The number of cells at 40 c for control were 4 x 10² cfu after 50 min, the number was decreased to 2.88 x 10² cfu with the extract. This decreasion was increased as the time progress for three temp. The best decreasing was 4 x 10 cfu at 60 c with extract and 3 x 10² cfu for control after 50 min. At 80 c^o it was higher a little bit at 60 c, it was 5 x 10¹ cfu with grape waste extract and 2.1 x 10² cfu for control.