The dead of winter may not be the time when most people's thoughts turn toward the allure of a hamburger on the grill. But from a food safety standpoint, it's probably the safest time there is to eat ground beef.
"The theory is that animals are carrying higher levels of E. coli during the summer months, and sometimes they may overwhelm the systems in place to control pathogen contamination in (processing) plants," says James Marsden, a professor of food safety and security at Kansas State University.
Research has been focusing "on how to level out that curve," says Marsden, also senior science adviser to the North American Meat Processors Association.
So industry and researchers are turning their sights to new technologies being deployed on the farm, the feedlot and at the slaughterhouse to knock E. coli O157:H7 down to winter levels all year round.
There's an unconventional mix at the forefront of this fight: bacteria-eating viruses, a paper-bleaching chemical, vaccines and a kind of yogurt for cattle.
The efforts come at a critical time. E. coli continues to make headlines -- so far this year the U.S. Department of Agriculture has overseen the recall of 40,000 pounds of beef potentially contaminated with O157:H7. The total for last year was about 2.1 million pounds. In the spring, Congress takes up a new bill targeting food safety.
There's clearly a push from the USDA to move the front lines against E. coli and other pathogens to the feedlot and farm. For the past decade, the industry has primarily focused on killing off threatening germs on carcasses, after the cattle have been slaughtered.
"To take the next big step forward on food safety, we need to do more to have fewer pathogens on food animals when they arrive at the slaughterhouse gate," Jerold Mande, USDA deputy undersecretary for food safety, said last month.
The new technologies constitute the first major shift in a decade in the battle against the wily bacteria that first burst into the public's consciousness with the Jack in the Box restaurant outbreaks of 1993 and has since killed hundreds.
None of which means that current steps to eliminate E. coli O157:H7 at the packing plant are any less important, Marsden says. Microbiologically, the biggest "bang for the buck" is cleaning the bacteria off the hide or the carcass to keep it from coming into contact with the meat, he says. Cattle carry O157:H7 in their gut, and it's transferred to hides by fecal contamination.
Commonly used techniques include carcass steam pasteurization, 180-degree water sprays to physically remove and kill bacteria, and vinegar rinses.
These have lowered levels of O157:H7 in beef substantially, says Jim Hodges of the American Meat Institute, a beef and pork producers industry group. "Frankly it's progress that I'm very proud of. Are we satisfied where we are? No. Is there more work to be done? Yes."
The hope is the new techniques will be able to bring O157:H7 levels from April to September down to cooler- weather numbers. Coupled with post-slaughter interventions, that could really help efforts to keep all beef free of E. coli O157:H7, Marsden says.
But making them work will take not just scientific acumen, but also a reconfiguration of how the industry thinks about risk. Many of these technologies must be administered on the farm or the ranch, months and sometimes years before cattle are slaughtered.
That makes it difficult to figure out just who will pay for them. Even the pennies-an-animal they cost can be daunting for ranchers working on razor-thin margins. And yet industry experts agree the farm is where the push to destroy E. coli O157:H7 must go.
A number of possible interventions are in the works. Each, it is hoped, might take down the incidence of E. coli O157:H7 by a factor of 100. Together they could substantially lower the toll inflicted by the disease, which can cause cramps, bloody diarrhea, kidney failure and death. The Centers for Disease Control and Prevention estimates about 73,480 people are infected each year, resulting in 600 deaths.
Vaccines: Gut warfare
Probably the most hopeful are vaccines that lower the amount of O157:H7 in cattle's guts. Two are furthest along, one from a Minnesota company called Epitopix and one by a Canadian company called Bioniche Life Sciences. Epitopix's vaccine has received preliminary approval from the USDA and is being tested in the USA. Bioniche's vaccine was approved in Canada last year and is in the approval process in the USA. In addition, scientists at the USDA's National Animal Disease Center in Ames, Iowa, have developed two more vaccines.
Field trials of the Epitopix vaccine showed that 86% of vaccinated cattle stopped shedding O157:H7 bacteria in their feces. Of those that still were shedding bacteria, there was a 98% reduction in the amount, says Daniel Thomson, a veterinarian and professor of Production Medicine at Kansas State University in Manhattan, Kan., who has studied the effectiveness of vaccine for the company.
The issue for cattlemen will be the costs of the two or three shots necessary to create immunity and the wear and tear on the cattle caused by bringing them in to be vaccinated. Going through the chute that holds them still while they're given the shot, necessary to safeguard workers, can cause some cattle to become agitated.
"You're looking at weight loss on the animal," says Mike Engler, president of Cactus Feeders, a feedlot in Amarillo, Texas, and former chairman of the National Cattlemen's Beef Association beef-safety committee. However, if current field trials show a significant reduction in the bacteria, it might become just "a cost of doing business, paying your dues for helping consumer confidence," he says.
Phages: A spray of bacteria fighters
Cattle walking through a car-wash-like spray of bacteria-eating viruses called phages sounds more science fiction than feedlot, but it's actually in use across the USA. These viruses, harmless to humans, are pronounced like age. Phages are already used in agriculture. For example, there's a phage that is sprayed on tomatoes and peppers to kill a spotting bacteria.
The phage binds to specific receptors on the surface of the E. coli cell, causing it to die, says Joan Todd, with Elanco Animal Health, the Eli Lilly subsidiary that makes the product.
In cattle, a phage that is specific to E. coli O157:H7 is sprayed on the animals one to four hours before they're slaughtered. "They like to have them soak," says Dan Schaefer, director of beef research and development at Cargill in Wichita. Cargill is testing the spray at one of its plants.
The phages used in Finalyse EC have been shown safe for the environment, humans and cattle, they "have no impact on other forms of life or the environment, and because they target specific bacteria, they will naturally break down without a suitable host," Todd says.
Probiotics: 'Exclusion' cultures
Basically these are bacterial cultures much like those in yogurt, given to cattle in their feed. They're called "competitive exclusion" cultures because they out-compete the bad bacteria and exclude them in the animals' guts. Michael Doyle, director of the Center for Food Safety at the University of Georgia in Griffin, spent years investigating them.
They can be persnickety.
One for E. coli O157:H7 "worked really well for a while and then it stopped working for a while," he says. Doses required are often higher than those claimed by the companies that sell them, he says. Currently these aren't approved by USDA or FDA as E. coli reduction methods, so the companies that market them can't make any specific claims for them.
Sodium chlorate: A 'suicide pill'
This chemical is used in part to do environmentally safe paper bleaching. But administered in extremely small amounts, it also plays a deadly trick on E. coli O157:H7 and salmonella.
In the oxygen-free environment of a cow's gut, these bacteria are able to obtain energy from nitrogen. But they can't tell the difference between nitrogen and chlorate, so if there's chlorate present, they try to use that. This turns the chlorate into bleach, killing the bacteria from the inside without harming the animal.
"It's like a suicide pill," says Robin Anderson, a microbiologist for USDA's Agriculture Research Service in College Station, Texas, who began work on the chemical in 1998. Eka Chemicals in Marietta, Ga., is working to license sodium chlorate. It's in the regulatory approval process with FDA.
Grain vs. high-quality hay
Research in Texas, Kansas and Idaho has shown that switching cattle from grain to a more expensive diet of high quality hay before slaughter may lower E. coli O157:H7 rates, though the findings have not always been consistent.
From an epidemiologic standpoint, it's clear that these pre-slaughter interventions lower the E. coli O157:H7 burden in the cattle, says Guy Loneragan, a professor of animal science and expert in O157:H7 in cattle at West Texas A&M University in Canyon, Texas.
The question is whether investing money on the ranch and feedlot will save money at the packing plant.
"Obviously the bottom line is food safety. But it's a question of where is the most appropriate place to invest the money," Loneragan says. "We're not quite sure of the extent of the financial reward and how it should be shared."
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