Cattle hides are more likely to be contaminated with E. coli at the feedlot than at the slaughterhouse and transport and lairage do not increase the number or isolation rate of E. coli O157 according to a recent study.

The study, conducted by Australian researchers and published in Foodborne Pathogens and Disease, conflicts with previous studies that have found transport and lairage can lead to increased levels of E. coli on cattle hides.

Understanding exactly where hides pick up E. coli in the beef production chain is important because the most common cause of carcass contamination is cross-contamination with hides during slaughter and processing.

Research regarding hide contamination is also critical in understanding how E. coli spreads between animals as there is often a greater prevalence of the pathogen on hides than in cattle feces.

“Understanding more about how carcasses and cattle become infected with E. coli O157 during production is vital for developing effective control measures,” notes the study, which found that 31 percent of cattle hides were contaminated at the feedlot and four percent were infected at the slaughterhouse.

A 2006 study by the U.S. Department of Agriculture’s (USDA’s) Agricultural Research Service, found a sharp increase in the frequency of E. coli O157 on hides from transport and lairage.

According to the USDA study, “Effective preharvest interventions to remove E. coli O157:H7 from the gut and hides of cattle may be negated by the time they entered the processing plant.”

Both the USDA and the Australian research team suggest further research is needed to better understand the mechanism of contamination during transport and lairage to help food safety regulators design better antimicrobial interventions.