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Reduction of Foodborne Pathogens on Cattle During Loading through Control of Dust Generation—Salmonella

Investigators
Miller, Mark
Institutions
Texas Tech University
Start date
2007
End date
2008
Objective
Previous research has demonstrated that pathogen loads carried on the hides of cattle increase from the time they leave a feedlot to the time they arrive at a harvest facility. The cause of this increase is not fully understood. Initially, it was hypothesized that cross-contamination was occurring while cattle were on trucks and that the increase in pathogens might be due to the cleanliness of the trucks. A 2004 research project indicated that the cleanliness of the truck did not necessarily impact pathogen loads on hides during transport. During the course of this research, the investigators observed that a cloud of dust was generated at every load-out. It was hypothesized that this air-borne particulate matter that is essentially pulverized fecal material may be at least partially responsible for the increase in pathogen prevalence. A subsequent research project supported that assumption. Exposure to the air-borne particulate matter generated from the surface of loading pens significantly increased the prevalence and quantity of E. coli O157 and Salmonella recovered from cattle hides.

Feedlot load-out areas may be a critical control point in reducing pathogen loads on beef carcasses. Control measures should be investigated to prevent increases in pathogen loads and ultimately to reduce pathogen loads on carcasses and in ground beef.

This research project was designed to determine if preventing dust generation would result in a decrease in Salmonella pathogen numbers by comparing results from a clean concrete load-out area in a feedlot versus a dirt loading area with no dust control measures.

More information
Findings: The researchers found no changes in the total population or total number of animals that tested positive for Salmonella before or after loading or between the clean and dirty load-out areas. On average, 80 percent of the animals at all sampling locations tested positive for Salmonella.

Samples collected from the pen floors in both the clean and dirty load-out areas were 100 percent positive for Salmonella. Very little of the Salmonella appeared to be transferred to the air. In the clean load-out area, no Salmonella was detected in the air samples, while in the dirty area 15 percent of the air samples tested positive for Salmonella.

The high initial Salmonella incidence on the hides of the cattle meant that the small amounts that appeared to be transferred to the air did not have significant impacts on the pathogen status of the animals.

For complete projects details, view the Project Summary.

Funding Source
Nat'l. Cattlemen's Beef Assoc.
Project number
BC-2007-3
Categories
Salmonella
Prevention and Control
Bacterial Pathogens
Escherichia coli