For the second time this year, romaine lettuce is being blamed for a large outbreak of illness caused by pathogenic forms of the bacteria Escherichia coli, or E. coli.  The latest multi-state alert was released by the CDC on November 26, warning of an outbreak originating in the north and central coastal regions of California, likely with a Watsonville epi-center.

The first outbreak of 2018 was this spring.  It proved fatal, causing more than 210 known cases across 32 states.  Five people were killed.  The Centers for Disease Control traced the pathogenic E. coli strain to an irrigation canal in Yuma, Arizona.

A thoughtful article published by Reveal’s Center for Investigative Reporting earlier this fall took a closer look at what might seem like an obvious question — why don’t we test the water that is used to irrigate fresh produce for harmful pathogens like E. coli O157?

It turns out that for many outbreaks, the science is clear — contaminated irrigation water is often the cause of fresh produce, food-borne illness outbreaks.  Irrigation-water canals run for miles through both cropland, grazing, and forested areas, as well as towns and cities.

Water than winds up in irrigation canals sometimes also falls on and then flows through land treated with unfinished, low-quality compost, or raw manure that can be loaded with potentially deadly pathogens.

Irrigation canals are magnets for frogs, birds, wild hogs, deer, mice, dogs, and many other critters, all of which can add their own bacterial and pathogen load into the water, and/or move bacteria and pathogens from other critters, including humans, into irrigation water. Carrion birds, in particular, are the Uber of pathogen flow across the landscape.

Bacteria and other pathogens from beef and dairy cattle operations pose the gravest risks when large concentrations of animals (e.g. a CAFO- concentrated animal feeding operation) are located within miles of fresh produce fields. One of the circuitous, complex ways that deadly bacteria can get into food became clear from the investigation of a tragic, food-poisoning episode in 2006 involving organic spinach at an Earthbound Farms field in California that left three people dead and hundreds ill.

Most of the land on the Paicines Ranch, which is about 50 mile northeast of Monterey, was used to graze cattle. A small portion of the 2,000-plus acre ranch was devoted to a series of blocks of organic spinach. Bacteria that started out in manure patties from the ranch’s grassfed beef cattle dried out during the unusually hot and dry August in 2006.

Then, over just one or a few days, a combination of animal traffic and ATVs pulverized some of the dried manure, and it became airborne. Wind blew it across recently-irrigated spinach. The manure-laden dust landed on still-wet spinach leaves, and stuck. The combination of heat, moisture, and nutrients over the next few days triggered rapid, and then massive bacterial growth.

Unfortunately, these huge bacterial loads in parts of the spinach blocks coincided with the harvest schedule. Load after load of the spinach was harvested and trucked to the processing plant.

The carefully managed, usually effective, triple-rinse system in the processing plant was simply overwhelmed by the load of bacteria. As a result, thousands of pounds of E. coli O157-contaminated spinach went into bags and plastic clamshells during a couple of shifts, and then moved across the country.

The system still, almost, worked. The vast majority of human illnesses were caused by spinach consumed near or beyond its “best used by” date. There was some evidence that the cold-chain had been broken on many truckloads shipped east of the Mississippi because of the high cost of diesel that summer, which made running refrigerator units 24-7 more expensive.

There were relatively few illnesses among people eating the spinach in the western U.S., where most was likely sold and consumed within 1 week of processing, or at most 2 weeks.

This 2006 spinach contamination episode tanked the national spinach market for months. It was among the sparks that led Congress to pass, finally, the Food Safety Modernization Act (FSMA) in 2010.  This legislation mandated FDA to develop and put into effect expansive, complex new rules to (hopefully) prevent similar outbreaks in the future.

New rules have been drafted and gone through closely followed rulemaking. Farmers are implementing new, preventive measures. Industry has upped its game across the board, and Earthbound Farm pioneered, and then imposed on itself the most sophisticated “test and hold” until safe fresh leafy green program in the world.

Solid progress, but in the 12 years since the 2006 spinach episode, and the eight years since passage of FSMA, the underlying threat has grown markedly more immediate and there has regrettably been some slippage in food-safety discipline and investments. And then _hit happens.

Many farmers felt the new FSMA rules were too onerous and expensive, and FDA officials appointed by the Trump administration agreed.  The agency decided to take a step back, and work on new set of “requirements that are less burdensome while protecting public health.”

The FDA hired an ex-produce industry lobbyist to work with growers on a new version of the rules.  Under the FDA’s updated timeline, testing of irrigation water won’t start until 2022, and then only annual testing of surface water irrigation sources will be required.

It’s hard to imagine, and indeed total folly, that one test annually will be enough to prevent future outbreaks. In the regions of California and Arizona where most of America’s fresh salad greens are grown, many growers already participate in voluntary food safety programs that require monthly sampling of irrigation water. Even with this frequent testing schedule, outbreaks still occur.

One food safety expert from the University of California, Davis quoted in the Reveal article calls FDA’s lack of action after the two serious outbreaks this year “mystifying…I can’t think of a reason to justify waiting four to six to eight years to get started.”

Plus, risk-based interventions are supposed to drive FSMA implementation. Irrigation water flowing through or near CAFOs is the epitome of high risk. It should be tested after every runoff event, if there is any chance the water will be applied to fresh produce down the line.

And remember, irrigation return flows constitute a runoff event and can carry bacteria from one irrigated field or pasture into the canals, just as an unusual rainstorm in the desert can move pathogens from feedlots or grazing lands into irrigation water sources.

Romaine is an important, readily and widely available, affordable source of needed vitamins, minerals, and antioxidants, and can bring a salad to life. But these outbreaks threaten to drive Romaine off our plates.

It’s time to confront what the science is clearly pointing to — livestock, especially stressed out cattle that shed more E. coli O157 than healthy cattle, and fresh produce cannot share the same landscape without extraordinary, preventive measures that go way beyond what FSMA requires.

Dealing with the fresh-produce threats posed by CAFOs is technically possible, and needs to get done. Then, attention must be directed to the more difficult challenge — how to deal with the birds and bees, the frogs, and those wild hogs.

Source:

Elizabeth Shogren and Susie Nielsen, “5 people died from eating lettuce, but Trump’s FDA still won’t make farms test water for bacteria,” Reveal, from The Center for Investigative Reporting, Published on: 09/27/2018, Date Accessed: 11/29/2018.