Making sure cattle are properly cared for before they are sent for processing, as well as how they are transported, can help reduce the spread of dangerous foodborne bacteria during beef processing, according to a review by University of Georgia researchers.
Led by Todd Callaway, professor in the Department of Animal and Dairy Science and courtesy faculty in the UGA Center for Food Safety, the researchers examined the different ways farmers can reduce harmful E. coli bacteria and other related Shiga toxin-producing E. coli (STEC) in cattle before the animals are harvested and processed.
The project, generously supported by the National Cattlemen’s Beef Association, examined harmful foodborne pathogens that are naturally found in the digestive tract of beef and dairy cattle. These pathogens cause severe illnesses in humans.
Callaway’s review investigates intervention strategies across the entire production chain, emphasizing management practices that slow the spread of the pathogen within the herd.
Intervention strategies for bacterial spread
Key interventions include managing the animal’s environment and diet. The housing pen is a major factor in transmission, as vehicles like manure, soil and contaminated urine stimulate bacterial growth.
Solutions involve using bedding materials such as sand and cleaning the pens to slow the spread. Management of animal density (crowding) and segregation is also critical, particularly with calves, which are more susceptible to STEC colonization and shed the bacteria more often than adults. In addition to housing, hygienic transport practices, including cleaning trailer surfaces and reducing trip distances to lessen animal stress, decrease the spread of contamination.
Feed and water management
Effective control of STEC in cattle begins with routine management of the animal’s gut environment. Water hygiene is a critical factor, as contaminated troughs are a major vector for pathogen spread, with up to 25% of farm water samples containing E. coli O157:H7. Increasing the frequency of trough cleaning is predicted to significantly increase the death rate of the bacteria.
Live animal treatments
Strategies for controlling Shiga toxin-producing E. coli (STEC) in live cattle focus on internal elimination and inhibition, with vaccination s one of the most effective tools, targeting bacterial proteins to significantly reduce fecal shedding rates. Other methods involve administering products through feed or water to manipulate the gut microbiome.
Hide washing also can reduce surface contamination just before processing, as the animal’s hide is the main source of carcass contamination.
Researchers must be careful when attempting to eliminate STEC from the gut microbiome, as removing one type of bacteria might create an empty ecological niche that a potentially more dangerous bacteria could occupy, Callaway noted.
Improving cross-system management
The analysis concludes that no single solution exists; instead, a multiple-hurdle approach — coordinating efforts across environmental, dietary and direct animal treatments — is key to successful control.
The project was generously supported by the National Cattlemen’s Beef Association. “This analysis brings together all the threads of science in one place that producers can use to make decisions,” he said. “Keeping this scientific knowledge accessible to non-scientists is critical to finding real-world solutions.”