Experts find better way to scrub milking hardware

University Park, Pa. -- Researchers at Penn State have devised a novel way to clean and disinfect milking equipment, using little more than salt water. The new method could be a safer and cheaper alternative to conventional cleaning systems.

"Concentrated chemicals used in the conventional cleaning are stored on the farm and on contact, they can cause serious burns in the eyes and on skin," says Ali Demirci, associate professor of agricultural and biological engineering. And, he says the chemicals are also expensive.

Most farms across the United States use some form of mechanized system to milk cows. The set-up basically comprises a rubber-lined suction cup that milks the cow and transfers the milk to a central refrigerating tank, through a series of pipes.

At day's end, the whole system is cleaned in a four-step process: first the pipes are rinsed with warm water to remove the milk. Then they are flushed with a chlorinated detergent at high temperature to remove soils such as fat and protein deposits, and then with a weak acid to neutralize the detergent and remove mineral deposits.

Finally, the pipes have to be sanitized with an EPA-registered sanitizing agent before they can be used again.

Demirci and his colleagues tried to clean the milk pipes using electrolyzed oxidizing water, as other researchers had shown its effectiveness in cleaning fresh produce, eggs, etc.

Electrolyzed oxidizing water is created when electric current flowing through two electrodes – immersed in a weak salt solution and separated by a membrane – produces an alkaline and an acidic solution.

It is not as expensive as the detergents, and can be made with just a little bit of salt and water," says Demirci, whose findings are published in the December 2005 issue of Transactions of the American Society of Agricultural Engineers.

To test how the new cleaning agent measured up to conventional detergent, the researchers flushed warm milk laden with bacteria down a series of pipes set up to mimic the system on a farm, and they compared the cleaning power of both in turns.

Results showed that in between 7.5 to 10 minutes, the electrolyzed oxidizing water was as effective in removing organic matter from the pipes, as conventional treatments.

"It is not harmful to the skin, and much cheaper. The alkaline detergent and acidic rinse in conventional systems of cleaning can be replaced with this water," says Demirci.

Other researchers include Stephen P. Walker, graduate student; Robert E. Graves, professor in the Department of Agricultural and Biological Engineering; Stephen B. Spencer, professor emeritus in the Department of Dairy and Animal Science; and Robert F. Roberts, associate professor in the Department of Food Science, all at Penn State.

The U.S. Department of Agriculture funded this project.