Contamination is the unintended introduction of foreign organisms, chemicals, or particulate matter into a culture, sample, environment or product that alters its composition and can compromise results or safety.
Explanation
In laboratory and industrial settings contamination describes the presence of substances or organisms that are not meant to be there. It can occur when media, reagents or equipment are not adequately sterilized or handled, when aseptic technique breaks down, or when environmental organisms are introduced from air, surfaces or personnel. In microbiology, contamination of blood cultures can lead to false-positive results where organisms not present in the bloodstream grow and mislead clinicians. In food and pharmaceutical production, microbial contaminants can spoil products or pose safety risks. Chemical contamination, such as heavy metals or solvents, may compromise water or drug purity. Preventing contamination requires clean work areas, proper sterilization of glassware and tools, use of laminar flow hoods, and careful handling to minimize airborne exposure. Technologists detect contamination by observing turbidity, unexpected colonies or precipitates, shifts in pH or color, or by testing for specific contaminants. Once detected, the contaminated sample is usually discarded because removing unwanted contaminants without altering the sample is difficult.
Practical Examples and Facts
- Skin flora introduced during venipuncture can contaminate blood cultures and produce false‑positive results, leading to unnecessary antibiotic treatment.
- Improperly cooked meat contaminated with Salmonella or Listeria can cause foodborne illness outbreaks.
- Mycoplasma contamination in mammalian cell lines often goes unnoticed but alters gene expression and metabolism.
- Chemical contamination of drinking water with industrial solvents or heavy metals requires filtration and monitoring to protect public health.
Contamination undermines the reliability of experimental results, threatens product quality and can impact patient safety. Maintaining aseptic technique, sterilizing materials and monitoring for signs of contamination are critical in microbiology, food production and manufacturing.
Related Terms: Contaminated Culture, Sterilization, Culture, Cross‑contamination, Cleanroom