PHILADELPHIA – The Pew Charitable Trust recently renewed its call for on-farm exposure-reduction strategies to be part of a comprehensive strategy to tackle foodborne illnesses.

In its “Opportunities to Improve Food Safety from Farm to Fork” issue brief, Pew focuses on probiotics and vaccines as on-farm interventions the organization found to be most effective at reducing livestock exposure to foodborne pathogens such as Salmonella and E. coli.

“A comprehensive approach to meat and poultry safety must begin at the farm level, because harmful bacteria often originate there and then enter the slaughterhouse with food animals,” Pew said in its issue brief. “Although certain interventions and handling practices during and after slaughter can reduce contamination risks, these measures are much more effective when farms and feedlots minimize contamination in their herds and flocks.”

Based on its research, Pew found that probiotics given at birth or hatching can help prevent pathogens from colonizing an animal’s lower intestinal tract. Vaccines also were cited by Pew as an effective on-farm intervention strategy to reduce livestock exposure to pathogens.

“Commercial E. coli O157:H7 vaccines have been demonstrated to significantly reduce fecal shedding in cattle,” Pew said. “One commercially available cattle vaccine was found to reduce the concentration of E. coli O157:H7 in fecal samples by 98 percent in large field trials with more than 2,500 cattle. Additionally, a mathematical model estimated that giving all cattle a vaccine that reduces fecal shedding by 50 percent could prevent up to 83 percent of human foodborne infections.”

Other interventions that show promise, Pew said, include sodium chlorate, which the US Dept. of Agriculture defines as a non-selective contact herbicide used as a spot treatment for perennial weeds. However, scientists studying the efficacy of adding sodium chlorate to the water or feed of livestock have found that, in low doses, sodium chlorate kills Salmonella typhimurium and E. coli O157:H7.

Pew noted that, “…more studies are needed on commercial farms, and sodium chlorate has not been approved for use in the United States.”