Could it have been the irrigation water? Or a heavy rain storm? How could cantaloupes become contaminated with Listeria to cause the outbreak that, as of Thursday, had sickened at least 76 people and claimed 14 lives in 18 states?
As the number of deaths and illnesses linked to tainted Colorado-grown cantaloupes continues to grow, so does speculation about what caused the contamination at Jensen Farms.
The U.S. Food and Drug Administration has said only that it found Listeria on melons, and on unspecified equipment in the production area of the packing operation in eastern Colorado. FDA investigators are working with state health authorities to determine what happened, and say they’ll use that information to find ways to prevent it from happening again.
But since 1990, cantaloupes have been the culprit in at least 36 outbreaks. This one is unusual only because it is the first attributed to Listeria, which has such a high mortality rate, relative to other foodborne pathogens. What’s not surprising is that cantaloupe, once again, is a source of foodborne illness.
Roy Costa, president of Environ Health Associates and a registered sanitarian, says that in the case of Jensen Farms, one theory may be that the bacteria was introduced into the packing plant via incoming produce.
“Given the wide spread of cases over time, this points to pre-harvest contamination as opposed to post-harvest contamination,” he wrote on his Food Safety & Environmental Health Blog.
Costa asks if the problem could have been contaminated irrigation water, given that the Arkansas River, the source of water for this melon-growing region, has been low due to drought, “and the access of the water source to all sorts of animal vectors is a very likely exposure pathway for Listeria monocytogenes.”
In an article in Food Safety News in March, Costa explained that because the cantaloupe’s rough skin can trap and hold bacteria, there are hazard points at every step of the supply chain, from growing, harvesting, packing, storage, transport, distribution and processing, to the consumer’s final cut into the fleshy fruit.
The FDA’s draft guidance on cantaloupes spells out the many ways cantaloupes can become contaminated.
For example, heavy rains can splash Listeria-containing soil onto cantaloupes in the field, where they also can come into contact with wildlife feces, which can carry Listeria or pathogens like Salmonella. Workers hand-turning melons can introduce pathogens and rind punctures from mechanical damage can be entry points for harmful bacteria.
Leaving culled melons in the field from prior harvests may attract wildlife and insects and result in soil contamination. So-called ground spots, where cantaloupes come in contact with soil, typically have significantly greater microbial populations that other parts of the rind.
Once harvested, cantaloupes are also susceptible to contamination in the packinghouse. The FDA guidance notes that soaking, spraying and icing cantaloupes to cool them can spread bacteria.
But the FDA’s recommended pathogen-prevention measures remain voluntary. Earlier this week, Caroline Smith DeWaal, food safety director of the Center for Science in the Public Interest, called the current outbreak “an urgent reminder that consumers are waiting for the FDA to release guidelines and regulations” to help keep pathogens out of produce.
She said the FDA should move rapidly to release the new guidelines and regulations, currently due for release in January 2012 and January 2013, respectively, and said Congress should fully fund the FDA to implement the Food Safety Modernization Act, to ensure that outbreaks like this stop breaking records.
Already the country’s deadliest foodborne illness incident in more than a decade, the cantaloupe Listeria outbreak toll count will likely continue through October, because people who ate contaminated melon last week may not get sick for some time. On Thursday, New Mexico confirmed a fifth death and Arkansas reported an illness.
Meanwhile, public health officials are still trying to track where all the recalled cantaloupes went. An earlier report that some of the cantaloupes were exported was incorrect.
And not all the cantaloupes were sold in stores. On Thursday, the Idaho Department of Health and Welfare, which has confirmed one outbreak-related illness, said 43,000 pounds of cantaloupes shipped from Jensen Farms to a company in Aberdeen, Idaho, were too ripe, so the melons were donated to the public between Aug. 28 and Sept. 2.
Among the surprising aspects of the E. coli O104:H4 outbreak that ravaged Germany this spring were the neurological side effects that caused some patients severe panic attacks, seizures and speech or motor impairment.
But fears that some of these outbreak victims might suffer permanent brain injury may be allayed, and there’s also preliminary evidence that some patients with severe kidney damage might not need long-term dialysis.
Those were some of the conclusions shared during Germany’s first clinical symposium on the outbreak, held Sept. 9 in Berlin and summarized online Thursday by Eurosurveillance.
The German Society of Nephrology had invited health experts and microbiologists to share what they’ve learned so far about the outbreak, linked to fenugreek sprouts, that killed 50 and sickened 4,321, including 852 who developed the kidney-damaging complication called hemolytic uremic syndrome, or HUS.
Neurologist Karin Weissenborn of Hannover Medical School, described her experiences with 43 patients – 42 who developed hemolytic uremic syndrome (HUS) and cognitive problems.Most, but not all of the patients, showed “a complete remission of neurological signs within weeks.”
Fourteen HUS patients, assessed with severe kidney damage and treated at Hamburg-Expender University, all recovered better than expected and none will need regular dialysis, according to researcher Udo Helmchen, who said initial histopathological ratings may have been misleading.
In other symposium highlights:
– Helge Karch, Munster University Clinic, said the Shiga toxin E. coli O104:H4 strain was first isolated in Germany 10 years ago, from a child with HUS. Though not identical to the 2011 outbreak strain, it showed similar features. But why the outbreak strain was so aggressive and spread so rapidly remains an open question. – Winifried Kern, University of Freiburg, said that based on the experience in Germany, antibiotics still cannot be generally recommended for enterohemorrhagic E. coli infections.
– Rolf Stahl, Hamburg-Eppendorf University Clinic, explained his rationale for the off-license use of Eculizumab (monoclonal antibody therapy, marketed as Soliris) for patients who weren’t responding to standard treatment options, such as plasma exchange therapy. But Stahl did not present results from the analysis of patients’ outcomes, leaving open the question as to whether Eculizumab was effective or not. (Last week, Soliris was approved for limited use in treating atypical HUS by the U.S. Food and Drug Administration.)
– The continued lack of evidence regarding the best treatment options for E. coli infections remains a concern, although some clinicians cited the benefits of using immunoabsorption for patients who went on to experience neurologic symptoms about 5 to 12 days after the onset of gastrointestinal symptoms.
– So far the E coli O104:H4 strain doesn’t appear to have become established as an endemic strain in Germany.
As big as the outbreak was, the illnesses were nevertheless mostly confined to one country. The experts at the symposium expressed an urgent need to share clinical data and experiences “to prepare for a similar event that might be more widespread.”
When it comes to ensuring that food enters the market carrying as few pathogens and insects as possible, the large majority of health, governmental and scholarly authorities seem to agree — food irradiation is an effective final safety measure.
In the face of the country’s worst outbreak of foodborne illness in more than 10 years, and after the devastating European E. coli epidemic this spring, interest in irradiation — a heat-free procedure that kills microorganisms in food through gamma, x-ray or electronic energy — continues to rise.
But while the Food and Drug Administration (FDA) has been approving new types of irradiated food for sale since the 1960s, few food processors have taken the leap to irradiating their products, leaving consumers little opportunity to get familiar with the treatment. At the same time, producers see irradiation as a big risk when consumer acceptance appears so shaky.
As a result, irradiation has fallen into a technological limbo, largely supported by the scientific community while going almost completely ignored by its intended end users. Whether through its additional costs, the misperception of it producing off-tastes or the general association of the word “radiation” with nuclear reactors and glowing skin, irradiation remains a niche treatment, used extensively on spices but nearly absent from meat and produce sections.
Irradiation proponents see lack of education as the main obstacle in the way of greater public acceptance, saying that too few consumers understand the technology and the level of safety it adds to meat and fresh produce.
“I think that more consumers would choose irradiated foods if they fully understood the process and the results so that they were comfortable with it,” said Joseph Sebranek, Ph.D., agriculture and life sciences professor at Iowa State University. “Part of the problem is that even though there is a lot of publicity about the need to improve food safety, the vast majority of consumers believe our food to already be very safe, and I think that they — subconsciously perhaps — don’t see a need for another process for safety.”
As a safety measure, irradiation occurs at the end of the production chain, with packaged food or ready-to-ship produce treated with precise doses of radiation. The process does not use any heat, but produces an effect similar to cooking: Good doses kill at least 99.99 percent of microorganisms in the food without producing the “off-flavor” associated with imprecise doses.
Sebranek argued that irradiation could have prevented Europe’s deadly E. coli outbreak and other outbreaks linked to fresh produce, because the treatment eliminates pathogens from fruits and vegetables while keeping their textures and chemistry intact.
And unlike chemical washes, irradiation kills organisms within the product, not just on the outside.
But the use of irradiation as a last-line-of-defense bothers others, such as Carol Tucker-Foreman, director of the Consumer Federation of America’s Food Policy Institute and coiner of the phrase, “Irradiated poop won’t make you sick, but it’s still poop.”
Tucker-Foreman said she and other irradiation opponents question the necessity of the technology when food makers should focus on improving sanitation standards at the beginning of the production chain. Many opponents use the “Band-aid” argument, suggesting irradiation offers the chance to zap away mistakes at the end of the chain instead of ensuring food starts safe and stays that way.
Those in the irradiation industry call that claim unfair.
Harlan Clemmons is the president of Sadex, a Sioux City, IA food irradiation facility and one of two companies in the United States to specialize in irradiating beef and other meat products. He said that his company requires all processors to manufacture food under a scientifically validated and verified Hazard Analysis & Critical Control Points (HACCP) plan and that foods not appearing to meet that criteria or failing to provide the proof in paperwork are not treated at their facility.
Sebranek, Tucker-Foreman and Clemmons all agree that no one will likely see more irradiated foods in marketplaces until customers start demanding them. The debate rests on whether or not they will, and whether or not the required label, the Radura will turn them away.
“I believe there’s 10 to 15 percent of the public who will never buy irradiated food and 10 to 15 percent of the public who will always buy it if available,” Clemmons said. “The rest don’t understand what irradiation is, and if provided the information, I believe the American consumer would accept it in most cases.”
Clemmons said that two-thirds of the foods Sadex irradiates are for pets, with beef and some produce rounding out the remaining third. He also cited a number of commonly used products that are sterilized with irradiation before human contact: Bandages, eye contact solution, cotton balls, diapers, all varieties of medical equipment.
“Be realistic: You wouldn’t think twice about using any of those products,” Clemmons said.
Currently, irradiated beef accounts for less than one-tenth of one percent of the beef market. Not only does poor public perception factor into the low availability, but the simple lack of infrastructure makes it a big logistical hurdle: For a processor to even have the option of selling irradiated beef, they need to send it either through Sadex in Iowa or the other facility in Florida, adding shipping costs onto the treatment’s price tag.
Tucker-Foreman said that irradiation has too many downsides to ever capture a large share of the market, and that the scientific community’s focus on irradiation is potentially taking valuable attention away from other improvements to the food system.
“The food industry has the option to use irradiation right now if they want to,” she said. “The fact is they’re not using it right now, and not just because they have to label it, but because it costs more and if you don’t do it with great precision, you get meat that doesn’t taste very good.”
After more than a decade in the irradiation business, Clemmons said he has seen a constant, gradual increase each year in the amount of irradiated beef Americans eat. Until it becomes more sought-out, however, he said he will not see it making dramatic leaps in availability.
“When I look at the big picture, we’re talking about prevention,” he said. “We want to reduce recalls. We have people getting sick, dying, getting debilitating diseases from foodborne pathogens that irradiation can help prevent. I don’t want to call it the silver bullet, but it is a bullet in the arsenal of available interventions.”
A new trade association has been mooted, but the current ‘big 5′ trade associations say there is no need. But what do you think?
A new trade association has been mooted, but the current ‘big 5′ trade associations say there is no need. But what do you think?
Japanese probiotic pioneer Yakult is now selling more than 118,000 bottles of its signature probiotic drink a day in the US (based on average sales Jan-June 2011) compared with 110,000 in mid-2010 and 90,000 in 2009.
