The following is excerpted from The Beef Report produced by Consumer Reports’ Food Safety and Sustainability Center. The full report can be found here.
The danger of superbugs
Foodborne illness caused by drug-resistant bacteria, such as the antibiotic-resistant strains of salmonella that have caused beef-related outbreaks in recent years, are also a major cause for concern. Infections caused by drug-resistant bacteria can be more difficult to treat and are a major public health problem.
In fact, the CDC (Centers for Disease Control and Prevention) estimates that each year more than 23,000 people die as a result of an infection caused by antibiotic-resistant bacteria. Despite the importance and prevalence of that problem, the government does not have requirements related to antibiotic-resistant bacteria in any meat product.
Two of the most important bacteria responsible for outbreaks attributed to ground beef are toxin-producing E. coli and salmonella.
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Shiga toxin-producing E. coli
Although most cases of foodborne illness are simple cases of vomiting and diarrhea that resolve after a day or so, some bacteria found in ground beef, such as Shiga toxin-producing E. coli (STEC) can be very dangerous. STEC produces Shiga toxin and can cause severe illness that can last five to seven days and even be so severe that infections require hospital treatment.
Additionally, some people can be left with a life-threatening condition called hemolytic uremic syndrome, which damages the kidneys. STECs are also concerning because they can cause those serious infections at relatively low infectious doses. The STECs can live in the cattle’s gut and are often found on hides, but they cause disease only in humans, not in the cattle.
Recent data published by the CDC show that incidence of illness caused by E. coli 0157:H7 in the U.S. decreased in 2014 to 0.92 cases per 100,000 people, compared with the incidences measured in 2006 to 2008 or 2011 to 2013; the incidence of infections caused by non-0157:H7 STECs and other pathogens did not decrease and remained higher than target rates defined in the government’s Healthy People 2020 goals.
Since 1994, the USDA has considered E. coli 0157:H7 in ground beef to be an adulterant, and in 2012, it added six of the most common non-0157:H7 E. coli STECs (the “Big 6”) to the list of adulterants.
That means that if those bacteria are found during processing in ground beef or in intact beef destined to become ground beef, the product cannot be sold unless it is to be further processed (cooked). Controls for those toxic STEC E. coli are included as part of Hazard Analysis & Critical Control Points (HACCP) at processing plants, and if any are detected, the product is considered adulterated and must be discarded, and the plant must report the result to FSIS.
FSIS does not actually require plants to do regular testing for E. coli 0157:H7 or other pathogens that may cause severe food poisoning, but only for generic E. coli. Generic E. coli is considered by FSIS to be a measure of fecal contamination and a measure of the effectiveness of sanitation in plants, yet there is no performance standard for generic E. coli.
Consumer Reports believes there should be performance standards for filth indicator organisms such as generic E. coli, as well as required tests for STECs. FSIS conducts its own testing for E. coli 0157:H7 and other STECs in beef at processing plants, but there are important limitations, including the frequency and prior notice of inspection to establishments regarding sampling, which could allow plants to temporarily alter procedures.
Interestingly, there are a number of factors related to the way cattle are raised that may affect their levels of generic E. coli and E. coli 0157:H7 within and shed from their intestines. For example, cattle eating grain-based diets appear to shed higher levels of generic E. coli than forage-fed animals. Studies of 0157:H7-specific shedding are suggestive of the same, although there are mixed results. Stress and feedlot confinement also foster poor hygiene practices that can increase contamination.
Although the reported prevalence of salmonella is low, the morbidity and mortality caused by foodborne illness from salmonella is significant, and drug resistance is particularly concerning because outbreak strains found in beef have been resistant to several important clinical antibiotics, including first-line agents prescribed to treat salmonella and other infections. Among the recent, large multi-state outbreaks that have been caused by salmonella-contaminated ground beef, the strain responsible for the 2011 outbreak was notable for its resistance to multiple antibiotics, including amoxicillin/clavulanic acid, ampicillin, ceftriaxone, cefoxitin, kanamycin, streptomycin, sulfisoxazole, and tetracycline. Ceftriaxone is an example of a recommended antibiotic prescribed for salmonella infections in humans, and strains resistant to those agents would be more difficult to treat, even in the hospital. FSIS has a performance standard of 7.5 per cent for salmonella in ground beef.