A lesser-known foodborne pathogen, Yersinia enterocolitica can cause fever, abdominal pain and diarrhea, lasting one to three weeks, according to the Centers for Disease Control and Prevention. There is approximately one confirmed infection per 100,000 people reported each year, but since these cases are severely under-reported, CDC estimates there are actually around 100,000 infections in the United States annually.
Consumer Reports tested 198 samples and found that while the vast majority were positive for Yersinia, only 3 to 7 percent were positive for the more common foodborne pathogens Salmonella, Staphylococcus aureus or Listeria monocytogenes.
According to the report, several of the isolates found were resistant to one or more antibiotics: 6 of the 8 Salmonella samples, 13 of the 14 Staphylococcus samples and 121 of the 132 Yersinia samples. The study also found MRSA on one sample.
The group points to the widespread use of antibiotics in agriculture as a key contributor to the resistance problem.
The report cites Robert Lawrence, a doctor who serves as director of the Center for a Liveable Future at the Johns Hopkins Bloomberg School of Public Health: “When you give low-dose antibiotics for growth promotion or for prophylaxis of infection, you end up killing off the susceptible bacteria, whether they’re E. coli, Salmonella, Campylobacter or other bacteria. And you continue to select for those bacteria that, through spontaneous mutations or transfer of genes from other resistant bacteria, allow them to be resistant to antibiotics.”
Rep. Louise Slaughter (D-NY), a vocal critic of agriculture’s use of antibiotics, reacted to the study on Tuesday calling the results “simply terrifying.”
“It’s getting harder and harder for the food processing industry and the FDA to ignore the fact that the overuse of antibiotics in animals is threatening public health,” said the congresswoman in a statement. “Their half-measures and voluntary guidelines are no longer enough – we must act swiftly to reverse this public health crisis.”
USDA affirms safety of pork products
The USDA responded to questions about the study by pointing out that the low levels of Salmonella and other common pathogens found by Consumer Reports show that pork processors are meeting federal food safety requirements.
“The findings reported in the article affirm that companies are meeting the established guidelines for protecting the public’s health,” said a USDA spokesperson, on background. “USDA will remain vigilant against emerging and evolving threats to the safety of America’s supply of meat, poultry and processed egg products, and we will continue to work with the industry to ensure companies are following food safety procedures in addition to looking for new ways to strengthen the protection of public health.”
The USDA’s Food Safety and Inspection Service does not test for Yersinia in its periodic baseline studies, which give the agency data on the prevalence of pathogens in different meat products. Since Consumer Reports found “very low” Salmonella contamination levels, the agency says, this indicates that the pork industry is adequately controlling pathogens.
FSIS also points out that last year 100 percent of pork processing establishments tested by the agency met the agency’s 2011 performance standards for Salmonella.
“FSIS selected Salmonella as the target organism for its pathogen reduction performance standards due, in part, to its high resistance to lethality treatments such as cooking. Eliminating Salmonella in a ready-to-eat pork product results in a product that also is safe from other pathogens, such as Yersinia.”
“Raw pork products are expected to be cooked sufficiently to destroy any pathogens of public health concern, including Salmonella and Yersinia,” added the agency.
There are a number of precautions consumers can take to avoid exposure to Yersinia. CDC recommends avoiding raw or undercooked pork, consuming only pasteurized dairy products, and washing hands when preparing food, after contact with animals and after handling raw meat.
Raw chitterlings, or pig intestines, are seen as a particular risk. CDC recommends cleaning hands and fingernails thoroughly with soap and water before touching infants or their toys, bottles or pacifiers after handling chitterlings.
Study finds traces of veterinary drug
The study also tested 240 additional samples of pork and found that 20 percent contained traces of ractopamine, a controversial beta-agonist drug widely used in pork production to boost feed efficiency and leanness.
Each sample that tested positive had concentrations at less than 5 parts per billion (ppb), which is below the U.S. Food and Drug Administration’s safety standard for pork muscle meat (50 ppb) and the recently adopted Codex Alimentarius Commission standard (10 ppb).
The drug, marketed to pork producers as Paylean, has been at the heart of recent trade controversies with the European Union, Taiwan and China, which each ban the drug and ask that U.S. meat imports are from pigs not fed ractopamine.
Citing incomplete safety data, Consumers Union, the policy and advocacy arm of Consumer Reports, has pressed for a ban on the drug.
A report published by nbcnews.com last year found that ractopamine had sparked more adverse drug experience reports for pigs than any other drug. According to FDA documents, the adverse reports complained that pigs suffered hyperactivity, trembling, broken limbs, inability to walk and death. FDA says such data do not establish that the drug caused the health problems, but the agency asked the drugmaker to add a warning label to the product in 2002.
PM Update: In response to questions about why the agency did not test for Yersinia in its 2011 baseline assessment after planning to do so, a USDA spokesperson told Food Safety News: “FSIS did consider testing for Yersinia in the more recent Market Hog Microbiological Baseline Survey, but concluded that available testing methods were not reliable for detecting pathogenic serotypes and genotypes of [Yersinia]. Instead, the baseline study focused resources on determining Salmonella prevalence and levels on market hog carcasses because it is widely accepted that Salmonella is more resistant to heat compared to [Yersinia] and lethality temperatures for Salmonella should effectively eliminate [Yersinia] in pork or other food products.”
This story has been updated.