Study finds most ground beef contains bacteria that can cause illness

Posted at 6:36 PM, Sep 10, 2015
and last updated 2015-09-10 18:36:50-04

Every time you eat a burger, you could be getting a side of bacteria with it. Most packages of ground beef in the grocery store contain at least one type of bacteria that could make you sick, according to a survey by Consumer Reports.

Researchers looked at 300 samples of ground beef from grocery stores in 26 cities across the United States. They included a range of leanness and cuts, from sirloin to chuck. About 40% of the packages bore labels stating they were “organic” or that the cows had been grass-fed or had not been given antibiotics.

The Consumer Reports team looked for five types of bacteria that have been found on beef, including E. coli O157, a strain that causes bloody diarrhea and abdominal pain and has been linked with the highest number of outbreaks of foodborne illnesses from beef.

What did they find?

Although the researchers did not detect E. coli O157, they did find at least one type of bacteria in every sample they tested. Most of the conventional or non-organic beef (82%) had more than one type of bacteria, as did a high proportion of the sustainable beef (58%), which the authors defined as coming from cows that were grass-fed or raised without antibiotics.

The bacteria the researchers found were concerning, including Clostridium perfringens and Staphylococcus aureus, both of which can cause diarrhea, cramps and other symptoms of food poisoning. Among the conventional samples, 19% and 55% were contaminated with these bacteria, respectively, whereas 18% and 27% of the sustainable samples were.

“Ground beef, like all meats, leads to a serious number of foodborne illnesses each year,” said Urvashi Rangan, executive director of the Food Safety and Sustainability Center at Consumer Reports and lead investigator of the report. “We think consumers should buy better beef (such as sustainable labels) and handle it more safely.”

What about E. coli?

Although it was not detected in this study, E. coli O157 is probably lurking in a small percentage of ground beef samples sold in grocery stores, Rangan said. And that low prevalence could add up to a lot of food poisoning given the amount of beef consumed in the United States, she added. The average American eats about 50 pounds of ground beef a year, according to the Consumer Reports article.

The study also found that nearly every sample of ground beef, both conventional and sustainably raised, had enterococcus bacteria, which can cause urinary tract infections associated with handling ground meat, Rangan said. The high prevalence of enterococcus suggests that a lot of fecal contamination happens during slaughter.

Some of the samples (18% of conventional and 9% of sustainable) harbored multi-drug resistant bacteria, so-called superbugs that are resistant to at least three types of antibiotics that are important as human medicines.

Findings are ‘definitely concerning’

The prevalence of microbes among ground beef samples in the study was surprising and “definitely concerning,” said Melinda Wilkins, the director of Michigan State University’s Online Master of Science in Food Safety Program, who was not involved in the analysis. “I think it should be a wake-up call.”

One of the biggest sources of contamination is probably the way that cattle are raised on feedlots, Wilkins said. Although grass-fed cows spend their whole lives in a pasture, most cattle produced in the United States live the end of their lives in concentrated feedlots. This can make it easier for bacteria to spread between cows, and also stresses the animals, making it harder for them to fight infections, Wilkins said.

Remember safe-handling procedures

It’s a great idea to buy organic meat, if possible, Wilkins said. However, she added, people should be careful when handling and cooking organic meat, just as they should with non-organic meat. That means keeping the meat cold, washing your hands and cleaning surfaces that touched the raw meat.

And although most people don’t want to use a food thermometer, it is important to help ensure that the inside of burgers is cooked to 160 degrees Fahrenheit in order to kill bacteria, she added.

“Just assume for safety purposes that (beef) could be contaminated and use all the food safety practices, but hopefully it is not contaminated,” Wilkins said.

These steps are especially important for the elderly, young children, and others who are more likely to have serious outcomes from foodborne illnesses, such as organ failure, she added.