Yogurt: A Yummy Bacterial Experiment

Until the 1800s microbial diseases were a mystery. This all changed after robert koch worked with diseases. He developed a postulate that we use today. It consists of identifying a disease, isolating it, implementing it into a healthy subject and successfully take out bacteria of the same origion now in the once healthy person. This can be used for good bacteria as well especially because most bacteria are not harmful. They are also the most populous form of life. Bacteria don't have a nucleus and move with tiny flagella. There are three types of bacteria, round, rod, and spiral shaped. Bacteria divide as fast as 15 minutes and can become billions overnight. In our lab we will be dealing with bacteria with different types of cell walls as well. The lactic acid bacteria that make the yogurt are gram positive, while the ecoli we are adding in a separate container is gram negative. We are using anaerobic bacteria that make lactic acid and do not require oxygen. This keeps harmful bacteria from eating the yogurt because it's acidic. In most countries a product may only be called yogurt only if the finishing project contains live bacteria. In our lab we will experiment with bacterial strains found in the yogurt sample and use it to create more yogurt out of fresh milk. There will be four tubes the first containing just milk, the second containing just yogurt, the third will contain yogurt and ampicilin which is an antibiotic and finally the fourth tube will contain ecoli in the milk solution. For my hypothesis I believe that the solution with milk only will remain unchained, the tube with milk and yogurt will begin to change, the tube with ampicilin and yogurt will kill of the yogurt bacteria, and the ecoli and milk will begin to smell rotten