Food safety study is encouraging for beef

Mar 9, 2012

The media hype over dangerous bacterial contamination of beef and animal ag breeding “superbugs” may be just that: hype.

A newly-released FDA study shows some encouraging trends in food safety and the battle against antibioticresistant bacteria. Not only does retail ground beef show lower contamination rates than poultry in many cases, but many of the bacterial contaminations found in beef are less resistant to antibiotics than those found in poultry.

Since 2002, the Center for Veterinary Medicine has conducted annual studies on the prevalence of foodborne bacteria in retail meat cases. The study is called the National Antimicrobial Resistance Monitoring System (NARMS). Keeping track of the bacteria’s resistances to common antibiotics and resistance trends over time is the primary concern.

NARMS follows salmonella, campylobacter, enterococcus and E. coli in retail chicken breasts, ground turkey, ground beef and pork chops.

Researchers in 11 states collected 10 samples of each meat type every month from a variety of retail grocery stores. The raw meat samples were stored in usual consumer refrigeration settings and cultured for contamination within four days of purchase. The culturing process tried to mimic unsafe handling practices that consumers might engage in, such as allowing raw meat to come to room temperature for over a day.

The NARMS 2010 findings for beef are encouraging. Positive cases of salmonella in ground beef were almost nonexistent at 0.5 percent of samples. This is compared to the 15.3 percent found in ground turkey, a common substitute for lean ground beef. Campylobacter, one of the bacteria NARMS looks for, hasn’t been studied in beef since 2008 due to its low incidence in prior years.

Of the other two bacteria, NARMS 2010 found a high incidence (90.2 percent positive) of enterococcus in ground beef samples. The bacterium is a natural part of both human and animal intestinal bacteria, but can cause serious infections in open wounds and in those with suppressed immune systems. Enterococci variations are of medical and food safety interest because of their natural antibiotic resistance and their widespread nature.

Despite the prevalence of enterococcus in ground beef samples, its resistance to streptogramins—a class of antibiotics effective in treating some of the most antibiotic-resistant bacteria—has decreased significantly. In 2002 when NARMS began, 46.2 percent of discovered enterococcus contaminations were resistant to streptogramins. In 2010, only 2.3 percent of enterococcus contaminations were resistant.

Enterococcus resistances to other antibiotics remained fairly steady and low in most cases, and decreasing in others. Resistance to lincosamides—a range of broad spectrum antibiotics used to treat a range of infections in humans—has increased to 94.7 percent. This is up from 91.9 percent in 2002, and the low of 78.8 percent in 2006.

Even though E. coli in retail meat is a popular scare tactic used against beef, NARMS 2010 shows poultry is the largest harbor for the bacterium. Only 58.5 percent of ground beef samples returned positive for E. coli, as compared to 77.6 percent in chicken breast and 80.2 percent in ground turkey.

Antibiotic-resistance in E. coli varied based on the antibiotic. Some resistances had increased, some decreased and some stayed steady. For the most part, changes in resistances up or down were minimal.

The notable exception is E. coli’s resistance to tetracyclines—another branch of antibiotics widely used to treat infections in humans. E. coli resistance to this important antibiotic has decreased since 2002. When NARMS began, there was a 30.9 percent resistance to tetracycline noted in discovered E. coli samples. The 2010 report shows resistance in only 22.7 percent of samples.

These trends are encouraging and fly in the face of popular “wisdom” which seems convinced superbugs are growing in every corner. The good work of the beef industry, coupled with the common sense of consumers who properly handle and cook their meat, will hopefully see these diminishing trends continue. — Kerry Halladay, WLJ Editor