Frontiers Of Biology

Yogurt the Yummy Bacteria

Most people associate bacteria with diseases and illnesses. But there are other kinds of bacteria that are helpful to humans and one of these is yogurt. Yes, yogurt is made from bacteria, specifically the Lactobacillus bulgaricus. This bacterium is actually only one of the several bacteria used in making yogurt.

How is it helpful to people, you ask. The bacterium feeds on milk and produces lactic acid. Lactic acid also helps preserve the milk. It then breaks down lactose. This is most helpful to people who are lactose intolerant because their digestive systems lack the enzyme to break down lactose to simple sugars. While fermenting milk, Lactobacillus bulgaricus produces a chemical known as acetaldehyde, which gives yogurt is yummy. Now, let us try making a batch of these helpful and yummy bacteria at home.

First, you need a starter. This can be bought at the grocery or at the health stores. If you can not find one, a cup of plain, unflavored yogurt can also be used as long as it has live cultures in it. The labels will tell you if there are live cultures in it or not. So read the labels before buying and save yourself the trip of going back to the store to exchange the product.

Next, heat up four cups of milk until hot but do not let it boil. Make sure the temperature is only between 95-120 degrees, just enough to kill some of the harmful bacteria present in milk. After which, let it cool down slightly before adding the live yogurt or starter.

Put the mixture in a sterilized jar or container and cover it. To sterilize a container, run them through dishwasher or wash it with very hot water.
After doing this, you are now all set to culture your homemade yogurt mixture. See, there are two ways in culturing yogurt mixture. You can either place the covered container in a clean plastic cooler and fill with hot water until it reaches just below the top of the containers or wrap the container in a heating pad and towels and set the heating pad on low to medium heat. On the first method, you need to constantly refill the cooler with hot water to ensure the temperature of the yogurt stays consistent. It is very important to keep the temperature consistent.

Heat the mixture and check it after about 3 1/2 to 4 hours. By this time, the mixture should have set-up. It means that it has a smooth, creamy consistency similar to a store-bought yogurt. If it still has not set-up, heat it again for 1-2 hours. You can then add your own flavoring, like vanilla, chocolate and you can even add your favorite fruits. After doing so, store in the refrigerator. It should keep for a couple of weeks. Now, you are ready to enjoy the fruits of your labor. A word of caution though, do not eat yogurt that has separated or has changed its consistency.