Researchers at the U.S. Department of Agriculture are conducting promising research looking at the role citrus byproducts could play in reducing pathogens in cattle. 

And, luckily, cows seem to really like orange peels. 


“Who knew? Those thick, sharp-tasting orange peels that people would never dream of eating are ‘snack heaven’ for cows,” reported the latest issue of Agriculture Research magazine, published by the USDA Agricultural Research Service. “Not only does the cow get good roughage and vitamins, but it also gets an antimicrobial boost from the peel’s essential oils.”

Turns out orange peel contains “d-limonene,” a naturally occurring compound that is used in many cleaning products as an antimicrobial agent.

Several natural plant compounds have shown promise as antibacterials in a variety of applications. Research has shown citrus essential oils, for example, can kill Staphylococcus aureus, Pseudomonas, Salmonella, and Escherichia coli.

USDA researchers have been exploring the food safety potential of citrus byproducts since 1999, according to ARS.

The team consists of ARS microbiologist Todd R. Callaway and animal scientist Tom S. Edrington, with the Food and Feed Safety Research Unit in College Station, TX, ARS animal scientist and research leader Jeffery Carroll with the Livestock Issues Research Unit in Lubbock, TX as well as John Arthington at the University of Florida in Ona. 

“While foodborne pathogens are found in the gut of food animals, non-antibiotic methods to reduce such pathogens in the live animal are important to improving food safety,” says Callaway.

The most recent research looked at how feeding processed orange peel pellets would impact pathogen counts. 

Researchers found a 10-fold reduction in Salmonella and E. coli O157:H7 in the animals’ intestinal contents. Callaway received a grant from the National Cattlemen’s Beef Association (Beef Checkoff funds) to help fund the work. 

These studies were accepted for publication in 2011 in the Journal of Food Protection and Foodborne Pathogens and Disease. 

“When approaching preharvest food safety, we take a ‘multiple-hurdle’ approach,” said Callaway. “These studies have the potential to lead to one more in a series of hurdles set up to prevent spread of foodborne pathogens.” 


Photo Courtesy USDA Agriculture Research Service