Bacteria are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit the air, soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria play a vital role in many stages of the nutrient cycle by recycling nutrients and the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition
Quick Answer
Plain English Explanation
In real life, bacteria are both helpful and harmful. They live on your skin, in your intestines, and in your home. Some help you digest food and boost immunity; others cause infections like strep throat or food poisoning. Understanding how to control bad bacteria while supporting good ones is key to staying healthy and maintaining a clean environment.
Step-by-step guide
Wash fresh vegetables thoroughly and slice into uniform pieces
Pack tightly into a sterilized glass jar, leaving 1–2 inches at the top
Pour saltwater brine (1 tablespoon salt per 1 cup water) over the veggies
Place a fermentation weight and lid on the jar, allowing gas to escape
Step-by-step guide
Clear the surface and wipe away visible debris
Spray with a diluted bleach solution (1 tablespoon bleach per gallon of water)
Let sit for at least 1 minute before wiping clean
Rinse with clean water if the surface will contact food again
Bacteria multiply rapidly in moist, warm environments with protein-rich foods like meat, dairy, and leftovers. Poor refrigeration or improper storage creates ideal conditions for contamination.
Making yogurt and kimchi through lactic acid fermentation
Producing antibiotics like penicillin in labs
Composting organic waste with beneficial microbes
Supporting digestive health via probiotics in supplements and foods
Cleaning wastewater using bacteria that break down pollutants
No, most bacteria are harmless or beneficial. Your gut contains trillions of good bacteria that aid digestion and protect against harmful microbes.
Wikipedia, 2026