Romaine Riddle: Why the Toxic Outbreak Eludes Food Investigators

 

Scientists checking out a toxic strain of E. coli that has raced across 25 states, sickening 121 people and killing one, are ready to identify the overall source because of the Yuma, Ariz., growing region.

But because the outbreak enters its second month, they still cannot find the contamination itself — it might be lurking within the area’s fields, water sources, harvesting equipment, processing plants, or distribution centers.

Federal officials predict that the outbreak, linked to romaine lettuce, will continue for several weeks.

It is the most important American E. coli flare-up since 2006 when tainted spinach sickened 199 people across 26 states. the present outbreak, and particularly obstacles to tracing it, underscore vulnerabilities within the monitoring of fresh produce.

“This is an era of massive data and technology — we need to really be ready to determine which farm a bag of lettuce came from,” said Sarah Sorscher, deputy director of regulatory affairs at the middle for Science within the Public Interest, a consumer group.

Complicating the investigation is that the incontrovertible fact that the romaine can come from a spread of farms and be commingled at points along with the availability chain.

A federal law enacted seven years ago was intended to stop such outbreaks — or a minimum of to shut them down swiftly.

But the rollout has been slowed by wrangling over compliance costs and details, and therefore the challenge of coaching tens of thousands of farmers and facility operators. Standards might not take full effect for years.

As a result, regulations developed to safeguard fresh produce delivered to colleges, restaurants, and grocery aisles nationwide aren't yet enforced with inspections.

For now, however, most farms do continue with federal recommendations referred to as good agricultural practices, or GAP, submitting to voluntary audits that check whether the produce is grown and packed to attenuate risk.

In 2010 Congress passed the Food Safety Modernization Act, authorizing the Food and Drug Administration to figure up comprehensive safety regulations.

The F.D.A. largely finalized the standards in 2015, prodded by a consumer lawsuit to stick to deadlines.

But the primary inspections of the most important farms don’t begin until next year.

Standards for farmers to watch water supplies are still being fine-tuned, and are scheduled piecemeal through 2024.

Virulent strains of E. coli do emerge, but a minimum of in beef, they will be neutralized by cooking.

And beef products, identified by bar codes and lot numbers, are easier to trace than produce.

But leafy greens are usually eaten raw, heightening the likelihood that a dangerous strain just like the latest one — Shiga toxin-producing E. coli O157: H7, which has caused renal failure in some patients — will infect the buyer.

Unlike products like flour, lettuce’s time period are short: Opportunities to check the offending crop range from limited to nil.

And because detailed reporting requirements to trace produce from field to supermarket haven't yet been hammered out, fine-tracing the source of contamination is exceedingly difficult.

Dirt Detectives

The initial alerts during this latest outbreak came from New Jersey.

On April 2, New Jersey Health Department investigators contacted officials at the Centers for Disease Control and Prevention. They were seeing a cluster of patients with E. coli infections.

“The initiative in any of those large outbreaks is to know we have a drag,” said Matthew Wise, deputy chief for outbreak response within the C.D.C.’s division of foodborne, waterborne, and environmental diseases.

Within days, more states called in, having identified a standard DNA fingerprint of the bacteria among their patients. The states uploaded their DNA reports to the C.D.C.’s database. On April 4, the C.D.C. contacted the F.D.A., which searches for contaminated products.

By April 5, the database indicated a multistate outbreak, and by subsequent day, C.D.C. researchers were working up a consistent questionnaire for state doctors to interview patients. They quickly zeroed in on leafy greens.

“Leafy green outbreaks are difficult to unravel,” said Dr. Wise, an epidemiologist.

“A lot of times people don’t even know what sort of lettuce they’ve eaten.” Realizing it had been mostly eaten in restaurants was a big clue, he added.

“Maybe it had been coming in big bags of prechopped lettuce.”

Between the 2 agencies and state partners, a battalion of several hundred investigators threw themselves into the hunt.

Ultimately, the complete measure of the outbreak won't be known. Usually, only the sickest patients seek medical help.

The C.D.C. estimates that for each case reported to the authorities, 20 to 30 more people fall ill from an equivalent strain; about 128,000 Americans are hospitalized and three,000 die annually from foodborne illnesses.

In a nationwide outreach to clinicians, C.D.C. officials have emphasized that Shiga toxin illnesses shouldn't be treated with antibiotics.

By April 13, the C.D.C. announced that 35 people from 11 states had become ill from an equivalent strain of E. coli, now linked to romaine lettuce from the Yuma region of Arizona.

F.D.A. investigators traced the sickness among a cluster of eight inmates at an Alaska prison back to whole-head romaine that had been harvested from Harrison Farms, within the Yuma area.

But they might not link other cases to an equivalent farm.

Harrison Farms may be a member of the Arizona Leafy Greens Marketing Agreement, a corporation of producers whose practices meet or exceed requirements established through the Food Safety Modernization Act, said Teressa Lopez, a spokeswoman for the group.

But it seems that romaine isn't romaine.

It is often processed and distributed in some ways — chopped, cored, sold as hearts, or maybe mixed with other greens in salad bags. The more processes, the more convoluted the trail.

The many patients who became ill after eating romaine at restaurants had not consumed the whole-head product.

Dr. Stephen Ostroff, the deputy commissioner for foods and medicine at the F.D.A., compared so-called traceback efforts to finding common points of intersection among flight paths on an airline magazine’s map.

Step by step, investigators work backward from each known point of contact for a patient, sifting through menu items, individual recollections, bills of lading, distribution sites, chopping and bagging facilities, locations where lettuce is cooled, trucks, and fields.

It is rarely linear. Finding a needle during a haystack may be a no-brainer compared with finding the source of the Shiga toxin-producing E. coli making its way around the country.

Officials say the bacteria almost certainly originated within the fecal material of an animal.