While scientists are scrambling to pinpoint the cause of the E. coli outbreak linked to bean and seed sprouts in northern Germany, a veteran sprouts system designer believes he has developed the technology that can produce “the perfect sprout.”
As of June 20, the outbreak had killed 40 people and sickened 3,598.
“If this technology had been used in the EU, those people would still be alive. I have no doubt about it,” Lincoln Neal, president of Tennessee-based Quicksilver Automated Systems (www.qasc.com/index.html), told Food Safety News.
According to the company’s website, Quicksilver provides state-of the art purification, propagation and processing systems for the largest sprout companies in North America.
Neal thinks the pathogen that caused the E. coli outbreak in Germany likely came in on the seeds, a conjecture that echoes warnings to sprout growers from the U.S. Food and Drug Administration that seeds are most often the source of most sprout-associated outbreaks.
For that reason, the agency recommends that sprout growers soak the seeds in a strong disinfecting solution, such as 20,000 ppm calcium hypochlorite, before sprouting them.
But Neal, a mechanical systems designer with a focus on disinfection, who describes himself as “a bit of a germophobe,” said soaking the seeds in a strong disinfecting solution at the onset just isn’t enough because the pathogens can lodge themselves into cracks and crevasses in the seeds.
Those cracks and crevasses, which he said in the microscopic world can be as large as the Grand Canyon, can provide safe harbor for the wily pathogens.
To make things more challenging yet, the seeds have a “somewhat oily surface” that can repel water. As a result, the surface tension on the outside of the seed can prevent the disinfectant from going into the cracks and crevasses in the seeds.
Neal compares that situation to the water that pools into droplets on the surface of a freshly waxed car.
He warns that if a sprout grower only disinfects the seeds at the beginning of the sprouting process, pathogens could still be lurking in the seeds, especially since sprout growers typically soak their seeds in disinfectant for only about an hour.
Neal also said that contrary to what some people in the industry assert, bacteria such as E. coli can not only hide in the microscopic cracks but can also get inside the sprouting seeds through those cracks.
Neal believes that the solution to that dilemma is easy enough: Use a method that sanitizes the seeds as they’re sprouting.
“We focus on the first 24 to 36 hours,” he said of his method
According to the company’s information about its Emerald Purifier/Sprouter, the equipment can get rid of embedded pathogens inside the seed shell by repeatedly flushing the inside of the seed hull with disinfectant solution at the moments it “changes, opens, ‘morphs,’ and detaches to release the sprout.
“Bacteria-occupied air cups and pockets are flushed out and disinfected,” says the company literature. “Full automatic wash cycles occur as the seed pops open and the microbes become exposed.”
“We go in when the seed is changing and by doing that we can get into the seed,” Neal said. “The machine persistently and automatically washes the product.”
Neal said that if the pathogens aren’t caught early on in the process, they can get into the sprouts themselves and that no amount of spray misting a disinfectant onto them can reach every square micron of the sprouts.
“Nipping it in the bud early on in the process is essential,” he said, adding that persistent disinfection doesn’t erode the nutritional value of the seeds and “is in full accord with the life process of the sprouts.”
“It doesn’t compromise germination or weaken it,” he said.
Looking at another FDA guideline for producing sprouts that involves testing the spent irrigation water that has flowed over the seeds, Neal sees drawbacks. FDA’s thinking behind that approach is that if there were any pathogens on the seeds themselves, they would multiply under the warm, moist conditions the seeds are sprouted in. If the testing, which typically occurs 48 hours into the sprouting process, reveals the presence of pathogens, then that batch can be thrown away, thus keeping it out of the marketplace.
But Neal said that as valuable as testing is, sprouting is a “hurry-up” sort of industry when it comes to shipping the fresh sprouts out to customers. For that reason, sometimes the sprouts are sent out before the test results of the spent irrigation water come back.
And even if a test-and-hold approach were adopted, Neal said that if the pathogens are deep inside the seed, the water won’t be able to reach them. They could actually be trapped and not be able to get out.
“It’s rare, but it could happen,” he said.
Then, too, Neal said that even with the safeguards many sprout growers are using, including FDA’s guidelines, a sobering fact keeps emerging: “Somehow these pathogens are getting by these sprouters.”
“That’s why I think upfront methods must be incorporated,” he said. “You’ve got to come in again and again and again to get the pathogens out. You have to be persistent — more persistent than the microbes. They’ve got brilliant programming in them to stay alive.”
These pathogens can be virulent. According to the FDA, a single surviving bacterium in a kilogram of seed can be enough to contaminate a whole batch of seeds.
Neal, who says he was called upon by the industry in 1985 to develop a sprout manufacturing package, has focused on modernizing an industry that had previously been more of a “flower-child kind of business.”
Fast forward to the present, and Neal says he’s probably designed more sprouting equipment “than anyone on the planet.”
Back then, immediate questions before him were “How can this problem be solved?” “And where are these pathogens coming from and what’s allowing them to proliferate.”
When evaluating the potential of his equipment to produce the perfect sprout, Neal said there are no “absolutes in microbiology.”
“But if the sprout growers follow our methods and don’t cheat, they can virtually eliminate the pathogens,” he said.
A blast of heat
Sydney Chang, owner of Chang Farm in Masachussetts, has invested many years of his life and many hundreds of thousands of dollars to expand and modernize his sprouting operation.
He started with a 7,200 square foot facility in 1993, added another 6,400 square feet in the late 1990s, and another 31,000 square feet last year.
“Sprouts are popular and healthy food,” he said. “If demand for them wasn’t growing, I wouldn’t be spending the money to do this.”
He relies on a heat pasteurization system widely used in Japan — but “still unique in this country” — that entails dipping the seeds in very hot water.
“It’s a quick kill,” he said, referring to pathogens that cause foodborne illnesses. “The hot water kills them on the surface of the seeds and if they’re under the surface.”
The water temperature the seeds are dipped in reaches 176 degrees, which is above the heat resistance of pathogens such as E. coli, Salmonella and Listeria.
He described the seed pasteurizer, which he
bought from Daisey Machinery
Co. in Japan, as “an expensive piece of equipment.”
“But I want to invest in food safety,” he said.
According to Daisey Machinery, heat pasteurization is a “natural and very effective” way to disinfect the seeds, which allows the seeds to be sanitized without the use of chemicals that could be harmful to the people operating the plant or to the environment.
With worker safety in mind, Chang also soaks the seeds in a chlorinated solution, but not at levels as high as recommended by the FDA. But he pointed out that FDA accepts those lower levels because the seeds have also been “heat pasteurized.”
Chang Farm currently sells several hundred thousands pounds of bean sprouts a week.
Instead of growing different crops of sprouts all in the same room, Chang has nine different sprouting rooms and harvests one room a day, which he says avoids the possibility of cross-contamination.
The growing containers are also steam cleaned after they’re washed.
Worker sanitation is another important part of the food-safety equation, with food-safety reviews held monthly. The farm also has food-safety specialists with advanced degrees on staff.
In addition, the sprouting facility has automatic door sanitizers that spray disinfectants on the floor where equipment and people enter.
“We have a modern state-of-the-art facility,” Chang said. “Everything is designed with sanitation in mind.”
Referring to the investment his farm has made in achieving this, Chang told Gazettenet.com in 2009 that it represents the family’s life savings, and a generous loan from the bank.
“We’ve put all of it in one basket in this business: me, my brother, my father, my mother, my wife. We want to give sprouts a good name. We’re serious about this business.”
What about irradiation?
Greg Henderson, editor and associate publisher of Drovers CattleNetwork, rankles at charges made against livestock production that link it to E. coli contamination of raw vegetables, including sprouts.
He said that while “many pundits seem eager to vilify livestock production, they don’t seem nearly as interested in telling the American public that technology has a solution for much of our E. coli contamination.”
That solution is irradiation and it’s currently underused, Henderson said in a June 13 commentary titled “Want safe food? Technology has a solution.”
Henderson describes irradiation as a process that exposes food to ionizing radiation to kill bacteria such as E. coli, as well as contaminants such as viruses and insects, and points out that it has been approved in 40 countries.
Even so, he said, it has not been widely adopted.
“That’s because of public perception,” he said, referring to fears of what he describes as an “extremely low level of radiation” that appear to be a “greater concern than our fear of E. coli and a host of other contaminants.”
Pointing to the E. coli outbreak in Germany, Henderson said it should spur interest in irradiation.
“Let’s stop pointing fingers and start irradiating our food,” he said.
According to the USDA, combining chlorination and irradiation can be an effective way to kill E. coli and Salmonella on alfalfa sprouts.
In 1999, USDA Agricultural Research Service scientists Donald W. Thayer, Kathleen T. Rajkowski and William F. Fett found that a treatment of irradiation and chlorine solution not only killed both organisms, but extended the shelf life of sprouts from about five days to more than a week.
In the tests, they used the same dose of irradiation as approved for irradiating meat. They also subjected the alfalfa seeds to various levels of chlorinated water.
According to the research results, the best way to eliminate pathogens would be a combination of irradiation and sanitation treatments. That’s because sprouts can be contaminated internally, which would prevent a surface disinfectant from working effectively.
But Quicksilver’s Lincoln Neal told Food Safety News that if the seed is irradiated sufficiently to kill foodborne pathogens, the seed germ (the heart of the seed for germination) almost invariably will be damaged.
“The results are compromised germination and dead seed,” he said. “Dead matter and weakened sprouts are less resistant to pathogens–thus arguably taking the infection issue back to square one.”
He also said that while irradiating finished sprouts can kill pathogens – it also kills and weakens the sprouts–again, decreasing resistance to pathogens that might be introduced during the interim to consumption. And again, arguably back to square one.
“And yes, selling a live food dead would surely tend to squelch the “sizzle” of appeal in the eye of the typical sprouts consumer,” he said.
Although the sprout farm in Lower Saxony state in northern Germany that has been indicated as the source of the E. coli-contaminated bean and seed sprouts is described as an organic farm, Mark Kastel, founder of The Cornucopia Institute, said that the problem in Germany is primarily about sprouts, not organic agriculture.
“People are using the term “organic farm,” Kastel said, “when the real elephant in the room — where the pathogens are originating — is not being discussed.”
He also said that according to recall data, of the 10 sprout recalls in the United States in the past 2.5 years (since April 2009), nine occurred because conventional sprouts tested positive for foodborne pathogens. In other words, 90 percent of the recalls involved conventionally grown sprouts.
German authorities have not yet discovered exactly where the pathogens that contaminated the sprouts from the organic farm linked to the outbreak came from.
Because the potentially fatal forms of E. coli are shed in animal feces, fresh vegetables are generally kept far apart from animals to prevent E. coli contamination.
Although organic and conventional sprouts are generally produced the same way, organic sprouts must be grown from certified organic seeds.
Testing the sprouts
FDA spokesman Douglas Karas said that for most foods, the FDA’s motto is “You can’t test your way to safety.”
He pointed out that having the right practices up front to minimize or prevent contamination are “the best bet” compared to testing the finished product. That’s because testing some of the finished product can give a grower a false sense of security about an entire batch if a piece or package tests negative.
Karas said that’s why the FDA recommends testing the water that has flowed through the entire lot of sprouts because it’s a good indicator of what’s in the sprouts overall, not just in a select sample. In addition, that sort of testing provides results before the product is shipped out, which allows growers to dump out contaminated batches.
Another logistical fact is that testing the sprouts involves smashing them up to release the pathogens. Obviously, if growers were to test all of their finished sprouts, they’d have nothing to send to market.
Once the sprouts are in “market channels,” such as at distribution centers, the USDA’s Microbiological Data Program can test alfalfa and clover sprouts by using a system that involves putting the sprouts in a bag with broth and pummeling them. MDP’s lead microbiologist
Shanker Reddy told Food Safety News that if pathogens are present, the process releases them from the sprouts, and stringent tests can be used to detect and identify them.
The benefit of MDP’s testing is that it can help keep contaminated products out of the marketplace — a far better approach to food safety than trying to track down the source of an outbreak after contaminated sprouts, or other fresh produce — have been bought and eaten.
This testing by MDP has been the basis of many sprout recalls.
As for whether consumers can protect themselves by washing the sprouts they bring them home, FDA researchers have found that if foodborne pathogens such as E. coli and Salmonella are on the finished sprouts, washing them only minimally decreases the amount of contamination.
Eating sprouts: yes or no?
According to the FDA, the United States has received no shipments of sprouts or sprout seeds from Germany and Spain since at least last October.
In response to the recent E. coli outbreak in Germany, the International Sprout Growers Association said in a June 11 press release that it wants to reassure consumers that it appears to be a localized event and one that isn’t affecting consumers worldwide.
The association “highly recommends” that the investigations into finding the source of the outbreak continue.
“By so doing, we can all benefit and further the efforts to make sprouts and all other raw foods the safest they can be,” says the press release.
At the same time, the association recommends that consumers continue to enjoy what it describes as the “the great health benefits, variety and taste of sprouts.”
It invites consumers to learn more about sprouts and their health benefits, as well as recipes featuring sprouts, by going to its website.
In the U.S., the FDA recommends that children, the elderly, pregnant women and people with weakened immune systems not eat any kind of raw sprouts. It also recommends cooking sprouts thoroughly to reduce the risk of illness.