WOOSTER, Ohio - The effects of nutrition and waste management on microbial pathogens found in manure may help to control their spread from the environment to humans.
Ohio State University and North Carolina State University researchers have received a four-year, $2.4 million United States Department of Agriculture (USDA) grant to study which zoonotic organisms are present in manure and in what amounts, and what happens to them when animal diets are changed or when the manure is subjected to various waste management treatments. Zoonotic organisms are those that can spread infection from animals to humans.
"Through different waste management technologies and the effects of certain nutrients, we want to see whether or not the pathogens survive," said Mo Saif, head of the Food Animal Health Research Program at the Ohio Agricultural Research and Development Center (OARDC) in Wooster, OH. "There are some feed ingredients that might have an inhibitory effect on pathogens. We also want to determine which management procedures work best in eliminating those pathogens." Animal manure, used as a natural fertilizer on fields and organic crops, is just one way that food-borne pathogens are spread in the environment. Food-borne illnesses are considered to be the most serious food safety problem in the United States.
According to the most recent data published by the Centers for Disease Control, food-borne diseases can potentially cause an estimated 325,000 serious illnesses resulting in hospitalizations, 76 million cases of gastrointestinal illnesses, and 5,000 deaths each year. Some of the more common food-borne pathogens include enteric viruses, E. coli, cryptosporidium, salmonella, brucella, listeria, clostridium, cyclospora, and chlamdiya - all of which can potentially be found in manure.
"Because of the concerns with food safety and the use of animal manure on agricultural land, we are basically going to study every food-borne pathogen in manure to see if there is a risk associated with public health," said Qijing Zhang, an Ohio State animal scientist and one of the project collaborators. More than 150 pathogens can cause zoonotic infections. "We'll then find the most effective technique to kill the pathogens." Farmers and organic gardeners who use manure to fertilize their crops are recommended to compost their manure before application, since the high temperature (at least 130 degrees Fahrenheit) that is generated over several weeks kills any pathogens that may be present.
"Many people are pushing for the composting technique," said Zhang. "I would say that there is pretty solid scientific data out there that points to the significance of treating animal manure before applying it to the land." Other Ohio State researchers involved in the project include Linda Saif, Ken Theil, Warren Dick, Fred Michel and Lucy Ward, all of whom work on the OARDC campus.