List of Terms: B
Return to Comprehensive List of Terms
>Bacteria (plural) or Bacterium (singular)
Food Safety Implication: Most bacteria are harmless and can even be beneficial, such as those used to make yogurt. However, harmful bacteria can cause foodborne illness in humans. In fact, out of all the micro-organisms of concern for food safety, bacteria pose the greatest threat to human health. Food can become contaminated with foodborne bacteria mainly from:
Where They Live: Bacteria are found everywhere. They live on and in the human body. For example, about 600 types of bacteria live on the skin, and saliva contains about 6 different kinds of bacteria. Water, wind, insects, plants, and animals can carry bacteria. They also live on clothes, human hair, room-temperature foods, and surfaces in our homes, schools, and workplaces.
How They Grow: Most bacteria multiply through a process called binary fission, a form of asexual reproduction in which the deoxyribonucleic acid (DNA) that holds all of the cell's genetic information doubles, the cell splits, and two independent cells are formed. One cell can double within 20 to 30 minutes.
You can't see, taste, or smell bacteria in food, but they can be present in food and multiply rapidly under the right conditions. That's why it's important to properly handle all foods.
To Survive and Reproduce, Bacteria Need:
How to Control Bacteria in Foods: One way is to keep cold food cold, meaning below the temperature where bacteria can grow. Usually, this is below 40° F (4° C), but some pathogenic bacteria can grow slowly at 32° F (0° C), the temperature at which water freezes.
Good Bacteria: Most bacteria are beneficial to us in our everyday lives, both inside our bodies and in other applications. Here are some examples of good bacteria:
Bacteria also assist with the production of certain foods such as cheese, buttermilk, sauerkraut, vinegar, and pickles. In certain crop plants like legumes, bacteria can take nitrogen from the air to the roots and change it into ammonia, which is one of several important compounds required for healthy plant growth.
Bacteria also play a role in recycling. They have the ability to decompose waste in the environment by breaking it down into nutrients that are useful to soil (also known as composting).
Harmful Bacteria: Pathogenic bacteria - those that are harmful - cause disease. They have the ability to cause disease by invading human tissue or producing toxic substances that can alter normal body functions. (See Pathogen for a list of the 12 Most Unwanted Bacteria that cause foodborne illness.)
Diseases Caused by Pathogenic Bacteria Include: Foodborne illness, tuberculosis, cholera, bacterial meningitis, Legionnaire's disease, rheumatic fever, typhoid, tetanus, pneumonia, strep throat, stomach ulcers, tooth decay, and skin infections.
Bacteria typically have one of three distinct shapes: cocci (round), bacilli (rod-shaped), or spirilla (spiral). Bacterial cells differ from other cells in that they do not have a well-defined nucleus enclosing their genetic material. Instead, bacteria have a nucleoid, which is a circular loop of double-stranded helical DNA that carries the genes.
> Bacteriophage (also known as Bacterial Virus or Phage)
How It Works: Thousands of varieties of phage exist, each of which may infect only one type or a few types of bacteria. During infection, a phage attaches to a bacterium and injects its genetic material into the cell. The phage takes over the metabolic machinery of the bacteria and produces new phage particles, which cause the bacteria to lyse (break open). This process releases many new phage, which seek out other bacteria to invade and repeat the cycle.
Phage Uses: Soon after making their independent discoveries of phages in the early 1900s, scientists Frederick Twort and Felix d'Herelle tried to use phages in treating human bacterial diseases, such as the bubonic plague and cholera. However, phage therapy was not successful. After the discovery of antibiotics in the 1940s, phage therapy was virtually abandoned. But with the rise of drug-resistant bacteria in the 1990s, the therapeutic potential of phages is receiving renewed attention.
>"Best If Used By" Date
>Binary Fission (see Bacteria)
> Binomial Nomenclature
In binomial nomenclature, the names of bacteria have a first (the genus) and last (species) name. For example for the bacterium, Escherichia coli, Escherichia is the genus and coli is the species. The first letter of genera (plural of genus) names are always capitalized, while species names receive a lower-case first letter. Since names are always in Latin, the names are italicized, like all foreign terms.
>Biotechnology (also known as Food Engineering or Genetic Engineering)
Food Safety Implication: Biotechnology is used to improve the quality and quantity of food.
How It Works: To change a plant's traits, scientists use a gun-like instrument to insert 1, 2, or 3 genes into the plant to give it new, advantageous characteristics. For animal production, scientists can select the traits they want and "genetically engineer" or introduce those genes into the animals.
Some Advantages of Biotechnology: