Yogurt, also known as sour milk, is a health dairy product popular for its rich nutrients and unique flavor. In 1875, French microbiologist Pasteur studied the fermentation process of fresh milk. He found many tiny creatures in sour milk, among which was lactobacillus. It was later discovered that lactobacillus was essential in the process of making yogurt during which lactobacillus decomposes the lactose in milk into lactic acid. That is to say, whenever we drink yogurt, we are drinking a lot of bacteria.

Crops are an integral part of our everyday diet. In order for crops to produce better yield and quality, fertilization is commonly used in the agriculture industry. A nitrogen-fixing bacterium has become a useful aid in boosting agricultural production. Plants cannot directly absorb nitrogen in the air, but with the help of this bacterium, plants will be able to feed on the nitrogenous fertilizer converted by the bacterium. As a result, we should thank bacteria for providing delicious food to us.

Baijiu, or Chinese spirits, is a specialty liquor in China with wide regional variations. Each type of baijiu uses a distinct type of bacteria during the fermentation process for the characteristic flavor profile. For example, lactobacillus added to mashed grains can produce a vast amount of lactic acid and ethyl lactate, which can be distilled into the liquor to present a unique flavor. Another example would be Clostridium anaerobic, which is the major contributor to the making of a type of baijiu with strong aroma. It is these tiny microbes that give unique tastes to our beloved liquors.

Penicillin is a drug we are all familiar with. It is an important antibiotic with high efficacy, low toxicity and wide clinical application. It has immensely protected us from bacterial infection and spearheaded the development of the antibiotic family. It was concentrated from a bacterium called Penicillium. As tiny as it is, the bacterium has saved tens of millions of human lives, making indelible contribution to human health.