Contamination of Food Items by Other Living Organisms Is Known As?
Biological contamination. It is the presence of harmful living organisms—bacteria, viruses, parasites, and fungi—in food. This is the correct choice over physical or chemical contamination, which involve objects or substances rather than living organisms.
The answer
Contamination of food by other living organisms is called biological contamination. It refers to the presence of harmful microorganisms and other living things—bacteria, viruses, parasites, and fungi (molds and yeasts)—in or on food. Because these organisms are alive, they can grow, multiply, and produce toxins, which makes biological contamination the leading cause of foodborne illness. Examples include Salmonella on raw poultry, E. coli in undercooked beef, Norovirus spread by an infected food handler, and Listeria in deli meats.
The key word in the question is living. Only biological contamination involves organisms that are alive, which is exactly what separates it from the other contamination types.
Why the other options are wrong
Food safety recognizes three main hazard types, plus cross-contamination as a mechanism. Ruling out the distractors:
- Physical contamination — non-living objects getting into food: glass shards, metal fragments, bits of bone, hair, jewelry, or plastic. These can injure a diner but are not living organisms.
- Chemical contamination — harmful substances like cleaning agents, sanitizers, pesticides, or toxic metals leaching from equipment. Again, chemicals are not alive.
- "Physical contamination" listed twice (a common trick option) — still refers to objects, not organisms, so it is incorrect for the same reason.
Only biological contamination fits the definition of contamination by other living organisms.
Comparing the contamination types
Understanding the differences is what most short answers leave out. Biological hazards grow and spread, so temperature control and hygiene stop them. Chemical hazards are prevented by storing chemicals away from food and rinsing surfaces. Physical hazards are prevented by inspection and keeping foreign objects out of the prep area. Each type demands a different control strategy, which is why identifying the type correctly matters.
Preventing biological contamination
Because these organisms are alive and multiply, control focuses on limiting their growth and spread:
- Cook foods to safe internal temperatures to kill pathogens.
- Hold foods out of the temperature danger zone (41°F–135°F / 5°C–57°C).
- Practice good personal hygiene—handwashing, no working while ill—to stop viruses and bacteria from handlers.
- Prevent cross-contamination by separating raw and ready-to-eat foods and using clean, sanitized surfaces and utensils.
Cross-contamination—transferring pathogens from one surface or food to another—is a common route for biological contamination, for example cutting vegetables on a board just used for raw chicken.
The bigger picture
Biological contamination is the most frequent and most dangerous of the three hazard types because living organisms reproduce quickly under the right conditions. Recognizing that "living organisms" points specifically to biological hazards—and knowing how they differ from chemical and physical hazards—lets food handlers apply the right prevention method and keep food safe.
| Biological | Harmful living organisms | Salmonella, E. coli, Norovirus, Listeria, mold | Raw foods, sick handlers, pests |
| Chemical | Harmful non-living substances | Cleaners, sanitizers, pesticides, toxic metals | Improper storage, equipment |
| Physical | Non-living foreign objects | Glass, metal, bone, hair, plastic | Poor handling, damaged tools |
Frequently asked
What are the four types of food contamination?
Food safety commonly recognizes biological, chemical, and physical contamination as the three hazard types, with cross-contamination as a mechanism that spreads them. Some texts list four categories by adding cross-contamination or allergens as a separate concern alongside the three main hazards.
What is the difference between biological and chemical contamination?
Biological contamination involves living organisms—bacteria, viruses, parasites, and fungi—that grow and multiply in food. Chemical contamination involves non-living harmful substances like cleaners, pesticides, or toxic metals. The distinction matters because each requires different prevention methods.
What are examples of biological contaminants?
Examples include bacteria such as Salmonella, E. coli, and Listeria; viruses like Norovirus and Hepatitis A; parasites such as Giardia and Trichinella; and fungi including molds and yeasts. These living organisms cause the majority of foodborne illnesses.
How can biological contamination be prevented?
Prevent it by cooking foods to safe internal temperatures, keeping food out of the temperature danger zone, practicing good personal hygiene and handwashing, excluding sick workers, and avoiding cross-contamination between raw and ready-to-eat foods using clean, sanitized surfaces.
What is cross-contamination?
Cross-contamination is the transfer of harmful organisms from one food, surface, or utensil to another—such as using a cutting board for raw chicken and then vegetables without cleaning. It is a common route for biological contamination and is prevented by separation and sanitizing.