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United States Department of Agriculture

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Water Hardness Plays a Role in Removing Bacteria from Chicken Skin / July 23, 2009 / News from the USDA Agricultural Research Service

Photo: Campylobacter cells. Link to photo information
Reducing water's hardness may increase its ability to rinse bacteria like Campylobacter from chicken during processing, according to new ARS research. Click the image for more information about it.


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Water Hardness Plays a Role in Removing Bacteria from Chicken Skin

By Sharon Durham
July 23, 2009

Reducing water hardness may increase its ability to remove bacteria from broiler chicken skin, according to Agricultural Research Service (ARS) scientists in Athens, Ga.  Water hardness varies in different geographical locations, but most water tested in the United States has some degree of hardness. 

“Hard” water has higher concentrations of dissolved minerals, such as calcium and magnesium.  Water is softened by removing these minerals, either mechanically or chemically. 

Microbiologist Arthur Hinton, Jr., and chemist Ronald Holser of the ARS Richard B. Russell Research Center in Athens conducted studies comparing the ability of very hard, moderately hard, and “soft” water to rinse away bacteria like Campylobacter, Staphylococcus and Pseudomonas from the skin of broiler chicken carcasses.

Very hard water was prepared by dissolving calcium chloride and magnesium chloride in distilled water, and moderately hard water was prepared by diluting one part very hard water with one part soft water.  Potassium citrate was used to reduce water hardness.

After five rinses in each water type, soft water removed up to 37 percent more bacteria from the chicken skin than did the other two water types.

Campylobacter bacteria are found in the intestinal tract of birds and can contaminate the bird’s carcass during processing. Staphylococcus is normally found on the skin of the birds, and Pseudomonas is a type of spoilage bacteria that can be found in processing water.

Processing water used in commercial poultry processing facilities can play a major role in the quality of poultry meat produced at the facility.  The pH, ammonia concentration, level of microbial contamination and hardness of water used in scald tanks, washers and chiller tanks are factors that may influence the ability of sanitizing procedures to remove microorganisms from carcasses during processing. 

Hinton’s and Holser’s studies indicate water hardness may be one of the characteristics of processing water that should be monitored by poultry processors.  By controlling water hardness, poultry processors may be able to improve the ability of processing water to remove bacteria from the skin of processed poultry.

This research was published recently in the International Journal of Poultry Science.

ARS is the principal intramural scientific research agency of the U.S. Department of Agriculture.
Last Modified: 7/23/2009