An investigation into dangerous bacteria found in ground beef products suggests sustainably-sourced meat may be healthier for consumers and better for the environment.
Researchers from Consumer Reports bought about 485 pounds of ground beef in 26 different cities from about 100 different stores over a three-week period and had the samples tested for five different bacteria, as well as for levels of antibiotic-resistance.
Some of the pathogens they looked for are indicators of filth and fecal contamination, while others are associated with beef-related illnesses, says Urvashi Rangan, the Director of Consumer Safety and Sustainability Group for Consumer Reports.
The researchers also wanted information about other organisms that aren't typically looked for on beef, but have a relation to food-borne illness — E. coli and Staphylococcus aureus, for example. In addition, they wanted to know if pathogen levels and antibiotic-resistance levels were different in conventionally produced beef than in more sustainably produced beef.
“We were able to find some pretty significant differences between those two groups when it came to certain bacteria levels, as well as how likely those bacteria were to be resistant to multiple antibiotics,” Rangan says.
Salmonella, for example, was found on about two percent of the conventional beef, Rangan says, but no salmonella was found on the sustainable samples. About 55 percent of conventional samples had Staphylococcus aureus, compared to 27 percent of sustainable samples.
Salmonella is a fairly potent pathogen, Rangan says. Like E. coli 0157, it doesn’t take much of it to make a person sick. On the other hand, humans can ingest some amount of the toxin from Staphylococcus aureus without becoming ill.
All of the pathogens they looked at can be quite serious, however, Rangan says, and they can all lead to serious health effects. E. coli 0157 probably has the most severe consequences: there are more deaths per incident of exposure with E. coli than with other pathogens.
The good news, Rangan says, is that they didn't find any E. coli 0157 or the shiga toxin-producing E. coli’s that are often associated with food borne illness on any of the beef samples. But they did find something else interesting.
“When you're looking at E. coli, you're also looking for the whole family of them,” Rangan explains. “We found a big difference between our conventional sample pool when it came to general E. coli levels — about 60 percent in our conventional samples versus about 40 percent in our sustainable sample pool.”
They found similar results in the antibiotic-resistance tests. “Eighteen percent of the bacteria we found on conventional beef were resistant to three or more antibiotic classes that are important in treating human infections,” Rangan says. “[In] the sustainable pool, only nine percent were resistant to three or more antibiotics.”
Even more interesting, Rangan says, when they extracted the results for grass-fed animals, only six percent of the bacteria on those samples had bacteria resistant to three or more antibiotic classes. This is significant, Rangan says, because it appears to confirm the results of other scientific studies.
“Researchers think that because of the natural diet, because the animals are not fed grain — which can create an acidic environment in the stomach which is very conducive to E. coli formation — grass-fed animals actually shed less E. coli in their manure. So these more sustainable systems can actually produce less E. coli even in the final product itself,” Rangan says.
All of the pathogens found in ground beef originate in manure, Rangan reminds us, so keeping beef safe is all about manure management, from the farm through processing and everything else down the line.
But if the most sustainably produced grass raised beef still has a six percent chance of having antibiotic-resistant bacteria on it, how prudent is it to eat ground beef at all?
“All raw meat will have bacteria. It is the nature of it,” Rangan says. “For us, it's about looking at illness rates that occur every year, compared to [the beef that’s] out there on the market and seeing if there are differences that will teach us how to make the system safer.”
We already know more sustainable production systems are better for the environment and better for the animals, Rangan says. Now we know they actually produce safer meat.
“More sustainable systems internalize the costs of environmental pollution. They make sure that it’s not occurring. They manage manure,” she says.
Fundamentally, the results of the study address the question of why antibiotics continue to be used in beef production on a daily basis.
“The fact that you see some resistance in some of the sustainable samples may be related to how persistent antibiotic resistance is in the environment,” she says. “So this is really about stopping the practices that are making the situation much worse than it needs to be.”