A method of making sampling tubes containing culture growth media by loading the sample tubes containing culture media into a tray that holds the sample tubes, placing the sample tube trays into a rack with shelving to hold the trays and tubes at a predetermined angle, and sterilizing and cooling the sample tubes in an autoclave or inspissator. The culture growth media solidifies at the predetermined slant angle and the sample tube trays are loaded into the packaging box used for shipment. The trays are subsequently used by the end user for processing microbial growth, including storing and collecting data about microbial samples.