October 28, 2014

Salmonella can also contaminate beef, says US disease control agency

So it's not just poultry that can be contaminated with salmonella. Even beef can, according to the US Centers for Disease Control and Prevention (CDCP).

The CDCP said salmonela caused 23% of all outbreaks attributed to beef from 2009 to 2013. In 2012, 46 people in nine states were infected by salmonella enteritidis in outbreaks attributed to ground beef, while in late 2012 to early 2013, 22 people in six states were infected by salmonella typhimurium.

Guy Loneragan, a veterinary epidemiologist and professor of food safety and public health at Texas Tech University, told a recent beef safety conference that lymph nodes were a significant source of salmonella in cattle.

"What we have found is that, in certain times of the year and in certain regions of the country, it's not uncommon to recover salmonella from some of the peripheral lymph nodes" in cattle, he said.

Loneragan, who is part of a research group working on the issue, said that in one study, the team found Salmonella among the lymph nodes within carcasses, and the lymph nodes may open up a different avenue for salmonella to contaminate ground beef.

Loneragan made a presentation at the conference about the development of a model for producing salmonella-positive lymph nodes and incorporating them into a beef-grinding process.

He said the model helps scientists understand the distribution of Salmonella in ground beef when it comes from lymph nodes rather than the animal's hide, which is the usual source.

He explained that understanding distribution is important for risk assessment and for developing interventions for process control.

Animal interventions may include vaccines or certain feeding approaches, and in-plant interventions may include treatment of trim before grinding, Loneragan said.