Health alert: almost all hamburger meat contains harmful bacteria

On Monday, a report on bacterial contamination in ground beef by Consumer Reports showed that all 300 packages of ground beef it tested contained E. coli or other bacteria consistent with fecal contamination.

Approximately 10 to 20 percent of these samples, which were purchased across the country, were contaminated with other types of bacteria that can cause illness in addition to fecal bacteria.

More than 40 percent of the samples contained staph aureus. In addition, 20 percent contained C. perfringens, the bacteria that causes almost one million cases food poisoning every year.

The investigation found that ground beef from grass-fed cattle or antibiotic-free beef contained less bacteria than beef made from animals that were given antibiotics and fattened on feedlots.

The majority of the 4.6 billion pounds of beef bought by Americans every year is produced conventionally.

Twice as many samples of conventional beef, or beef from animals that were given antibiotics, tested positive for "superbugs," bacteria resistant to multiple antibiotics, than antibiotic-free beef. In total, 18 percent of conventional beef tested positive for such superbugs.

However, the U.S. Department of Agriculture assured NBC News that none of the E. coli found by Consumer Reports was the same variety that causes outbreaks of severe illness.

Food safety experts suggest that people cook beef to 160 degrees in order to kill all bacteria that can potentially cause illness. It is also important to keep raw meat away from other foods to prevent possible contamination.

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