Cross-contamination

Adair P Hoover
Home & Garden Information Center

Cross-contamination Adair P. Hoover,©2015 HGIC, Clemson ExtensionCross-contamination, a common food safety term, occurs when harmful pathogens are transferred from one food to another during food preparation and cooking.

Cross-contamination can be particularly harmful when foodborne pathogens are transferred to a food that is not going to be cooked before it is served. A classic example is when a cutting board, that has been used to cut raw chicken, is then used to prepare fresh lettuce without being cleaned and sanitized in between.  The end result is that any harmful bacteria on the raw chicken will transfer on to the lettuce. If the lettuce is then served uncooked there will be no opportunity to kill the harmful pathogens. Ultimately, contaminated lettuce will be served and could make everyone who eats it sick. 

For another example of cross-contamination and a couple of minutes of entertainment, check out the following Clemson Extension video:  https://www.youtube.com/watch?v=QgErL3DvIy8

Avoiding cross-contamination is an important step in food safety. Keeping the following tips in mind when preparing food can help you to prevent a very unpleasant and possibly dangerous situation of your own:

  • Wash hands and all food preparation surfaces with soap and water before and after touching raw meat, poultry or fish. Bacteria on raw meat, fish or poultry can contaminate other foods such as bread or lettuce that will not be cooked.
  • Clean all cutting boards, knives, utensils and counter tops with warm, soapy water before food preparation begins.
  • Use one cutting board for raw meat, poultry or seafood, and a different cutting board for ready-to-eat foods, such as fresh fruits and vegetables, cheese and bread.
  • Sanitize cutting boards that have been in contact with raw meat, poultry or seafood. To sanitize, put the board in a solution of 1 tablespoon liquid chlorine bleach in a gallon of warm (not hot) water and leave for several minutes. Plastic cutting boards can also be sanitized in a dishwasher using the wash and dry cycle.
  • To sanitize kitchen counters, first wash with hot, soapy water. Then use 1 tablespoon unscented chlorine bleach in 1 gallon of water (or ¾ teaspoon in one quart of water) and spread on the counter. Let sit for several minutes and dry with paper towels.
  • Sanitize a non-metal kitchen sponge by heating it, while still wet, in a microwave oven for 1 to 1½ minutes. Avoid burns by allowing the sponge to cool before using it.
  • Use paper towels to clean up raw meat, poultry and seafood spills on kitchen counters and other surfaces. Wash kitchen cloths and towels that have been in contact with raw meat juices in the hot cycle of the washing machine and dry in the dryer before reusing them.

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