Food & Nutrition
Antimicrobial Properties of Copper May Aid in Food Safety
By American Society for Microbiology
Jun 15, 2006, 17:58

A new study suggests that the use of cast copper alloys during food processing may help prevent cross-contamination of E. coli better than stainless steel say researchers from the University of Southampton, United Kingdom and Copper Development Association Inc., New York. Their findings appear in the June 2006 issue of the journal Applied and Environmental Microbiology.

Escherichia coli O157 is one of the most serious food-borne pathogens worldwide causing physical effects ranging from diarrhea to hemorrhagic colitis. Cattle is a major reservoir of E. coli O157, therefore outbreaks are primarily associated with consumption of undercooked ground beef. Cross-contamination of infected meat with points of contact during processing makes it extremely difficult to maintain. Currently, stainless steel has been the metal of choice for food preparation, however, studies have shown that even with consistent cleaning and sanitation procedures bacteria can remain viable.

In the study cast copper alloys (a mixture of metals containing varying degrees of copper) and stainless steel were exposed to E. coli, some mixed with beef juice, some without, and incubated at either 22 degrees Celsius or 4 degrees Celsius for up to six hours. Results showed that three copper alloys not exposed to beef juice completely killed E. coli when stored at 22 degrees Celsius and only the alloys containing high quantities of copper (85% or more) significantly reduced E. coli at 4 degrees Celsius. With beef juice, alloys consisting of 93% or more copper greatly reduced E. coli at 4 degrees Celsius, while only one alloy (containing 95% copper) completely killed the bacterium at 22 degrees. No significant reduction in cell numbers was reported for stainless steel.

"These results clearly demonstrate the antimicrobial properties of cast copper alloys with regard to E. coli O157, and consequently these alloys have the potential to aid in food safety," say the researchers.

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