Scientists from the University of Arkansas and Colorado State University are investigating the use of orange oil as an E. coli inhibitor on the chilled carcasses of cattle.

In a May 2012 Journal of Food Science article, researchers say that a 1% solution of cold pressed terpeneless Valencia orange oil at the chilling stage of the carcass could be an additional step to reduce pathogens.

Orange oil is already used in some livestock and household preparations for pest control. Commercial pesticide companies derive the oil from the orange through extraction, steam distillation or as a by-product of orange juice production. The orange oil poses no danger to humans, pets or livestock and therefore is attractive as a potential mitigator of E. coli and other pathogens.

The National Cattlemen’s Beef Association has been involved with scientists studying orange oil as a pathogen reducer since 2009.

Citrus pulp as a feed
Not only may orange oil be effective applied to the chilled carcass, but a USDA-Agricultural Research Services report says they may beneficial in the feed of live animals as well. It says citrus essential oils have been part of the human diet for hundreds of years, and their effects on bacterial growth and survival are well studied. Citrus oils have been known to kill Staphylococcus aureus, Pseudomonas, Salmonella, and Escherichia coli. 

The ARS study describes feeding orange pulp to cattle to reduce enteric pathogens. It says initial laboratory results published in 2005 indicated that citrus products included in ruminant rations decreased pregastric gut and lower-gut populations of E. coli O157:H7 and a variant of S. enterica, S. Typhimurium, without causing a significant change in fermentation end products.