Contributing Factor Definitions

At a glance

Review technical definitions for the 30 contributing factors for foodborne illness outbreaks, organized around the three types of contributing factors (contamination, proliferation, and survival). Staff from CDC, the Food and Drug Administration (FDA), and state health departments helped revise these contributing factors to show how foodborne illness outbreaks evolve.

Three types of contributing factors: contamination, proliferation, and survival.

Old definitions

Note‎

Participants in our National Environmental Assessment Reporting System (NEARS) started using these revised contributing factor definitions as of January 1, 2022, for outbreaks occurring in 2022 or later. The 2009-2021 definitions are still available for reporting outbreaks that started before 2022.

Contamination

Contamination contributing factors are factors that introduce or otherwise permit contamination of food. These factors relate to how the etiologic agent got onto or into the food.

Food worker standing at a counter with food on it.

Contamination Contributing Factors

Review definitions for contamination contributing factors to outbreaks.

Proliferation

For bacterial and fungal outbreaks only.

Proliferation contributing factors are factors that allow proliferation of etiologic agents. These factors relate to how the pathogen was able to increase in numbers and/or produce toxic products before the food was ingested.

Plate of sliced deli meat on a counter with a clock in the background.

Proliferation Contributing Factors

Review definitions for proliferation contributing factors to outbreaks.

Survival

For bacterial, viral, parasitic, or fungal outbreaks only.

Survival factors are factors that allow pathogens to survive or that fail to inactivate the contaminant. These factors relate to processes that should have killed or reduced the pathogen population to below an infectious dose but did not because of one of these factors.

Hamburger patty on a grill with a thermometer in the meat.

Survival Contributing Factors

Review definitions for survival contributing factors to outbreaks.
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Content Source:
National Center for Environmental Health