Each month, the U.S. Department of Agriculture publishes a list calling out chicken processing plants across the country that have failed salmonella testing. Notably absent from its October report: the three Foster Farms plants that have been linked to a virulent outbreak.
Those facilities -- two in Fresno and the company's main plant in Livingston -- easily passed, receiving high marks from federal inspectors for controlling the human pathogen on their young chicken carcasses, according to Daniel Engeljohn, assistant administrator with the USDA's Food Safety and Inspection Service.
But inspectors don't routinely test the chicken for salmonella once it's chopped up into parts, like drumsticks, breasts and thighs, to be packaged and sold. And it's in that secondary processing that food safety regulators speculate the contamination may have spread.
The outbreak has exposed weaknesses in the country's food safety system, which is designed to spot salmonella at one stop in the journey from the typical bird's birth to its perch in the supermarket refrigerator case. And, even as the plants continue operating, neither federal regulators nor Foster Farms officials have publicly pinpointed the cause of the outbreak.
There are no federal rules for how much salmonella is acceptable in chicken parts. Federal regulators say they're developing them. But even if those rules had existed already, it is unlikely they would have caught the problem at the Foster Farms plants.
And if inspectors had raised the alarm before the outbreak of foodborne illness, the best they could have done is pressure the plants to improve their processes. A famous court case involving beef and salmonella found the USDA did not have the authority to close a plant that consistently failed its testing for the human pathogen.
Meanwhile, the rate of salmonella infection in the United States is holding steady with no sign of going down, while Europe has managed to cut its rate dramatically in a five-year period, according to the European Food Safety Authority. That's in part because some European countries test for salmonella at the beginning of the process -- when the chickens are being raised for slaughter.
In the current outbreak traced to the Foster Farms plants, 338 people had been reported infected with seven strains of salmonella Heidelberg as of Oct. 17. Those strains are antibiotic-resistant, which might be contributing to the high rate of hospitalization associated with the outbreak. It has sickened people in 20 states and Puerto Rico, though most of the cases have occurred in California. For every reported illness from salmonella, the Centers for Disease Control and Prevention estimates 29 more cases might remain unreported, putting the likely toll closer to 10,000 infections.
Since January, federal inspectors have documented food safety violations at the three Foster Farms plants, including fecal material on carcasses. But federal food safety officials say those violations are no worse than what you'd see in a typical chicken processing plant.
And those same plants had such a strong record on salmonella that their young chicken carcasses were tested for it by federal inspectors only about once every two years, Engeljohn said.
In the most recent tests, which took place within the year, fewer than 2% of the carcasses tested were tainted with the human pathogen. Under federal rules, no more than 7.5% of broilers tested should show evidence of the bacteria, which underscores that some salmonella is tolerated in chicken meat in the United States.
At these three Foster Farms facilities, something appears to have gone wrong later in the process. Exactly what happened is still unclear. If the company knows what happened, it has not disclosed it.
The federal government does not typically inspect chicken for salmonella once it's been chopped into parts from whole. It did so at these three plants once the outbreak happened, though the rates it discovered were only slightly higher than those found at other plants across the country.
The government estimates 24% of all chicken parts have salmonella at plants nationwide. The Foster Farms plants had between 25% and 27%.
In response to the outbreak in early October, the USDA's Food Safety and Inspection Service threatened to shut down the plants by withdrawing its inspectors, who have to be on-site for the plants to operate. Under pressure, the company said it would implement new processes. The plants stayed open.
One change at the plants: Chicken parts now will be washed with an antimicrobial treatment, according to the USDA. This is done already at another Foster Farms plant in Washington state, where federal inspectors found a much lower rate of salmonella on chicken parts.
"They're treating their parts with an additional antimicrobial treatment, which all of the rest of the industry does not use, which we're encouraging the industry to do," Engeljohn said.
Regulators do not have the authority to mandate that all plants adopt that treatment.
Yet, even if the federal government develops performance standards for salmonella on chicken parts, the USDA is unlikely to shut down facilities that do not meet those standards before people get sick. A pivotal 2001 court case, Supreme Beef Processors v. USDA, found that the agency cannot close a meat processing plant that consistently fails salmonella testing because, in this country, the bacteria is not considered an "adulterant" in meat.
That means it's treated as an unfortunate food safety hazard and a natural constituent of poultry that consumers should cook properly to destroy. Once something is considered an adulterant, like E. coli O157:H7 in ground beef, it cannot legally be sold as food for humans unless it has been inactivated by cooking or some other process.
When a poultry plant fails its salmonella testing, federal inspectors put pressure on the company to improve its processes. Plants that have failed also are tested more often to ensure they're cleaning up. If a facility repeatedly fails these tests, the agency can threaten to withdraw its inspectors to shut it down. But it is unlikely that the USDA will actually do so, or else risk being sued as it was in the Supreme Beef case.
Nine questions and answers about salmonella
An outbreak of an especially strong form of salmonella has sickened hundreds of people in 20 states. But how it happened largely has remained a mystery. Here's what we know about some of the more pressing questions surrounding the outbreak. Have other questions? Email the reporter at firstname.lastname@example.org.
What led to the salmonella outbreak?
It's still unknown. Foster Farms, the company that owns the processing plants linked to the outbreak, hasn't said if it knows. Federal regulators suspect the bacteria spread when whole chickens were cut into parts to be packaged and sold, which is after the point regulators test for salmonella.
Chicken from those plants is still being sold. Why?
It is legal to sell chicken in the United States that has salmonella in it.
Food recalls technically are voluntary, but the U.S. Department of Agriculture has not encouraged Foster Farms to pull chicken from these three California plants out of supermarkets.
"We have to be confident that what we decide to pull out of the market is what we can support in the evidence," said Daniel Engeljohn, assistant administrator with the USDA's Food Safety and Inspection Service.
The company and the government say you should be fine if you properly cook and handle the meat.
So why did so many people get so sick?
The strains of salmonella Heidelberg implicated in the outbreak are especially strong. They are antibiotic-resistant, which means that drugs that normally would be able to kill the bacteria or stop its growth don't work.
Why are these bacteria antibiotic-resistant?
Some livestock are fed antibiotics to make them grow faster and to prevent and treat disease. The bacteria in livestock have responded, leading to an increase in the prevalence of antibiotic-resistant bacteria.
That's bad news for humans who get infected with the bacteria. Antibiotic resistance may contribute to the bacteria's virulence and make it harder to treat infection in humans.
We can see evidence of that toll in the current outbreak; 40 percent of the reported victims have been hospitalized. That is about twice the typical hospitalization rate in a salmonella outbreak.
Why didn't this problem get caught earlier by USDA inspectors?
The food inspection system is designed to flag plants that have especially high amounts of the bacteria in their meat, but testing is infrequent.
The three Foster Farms plants in question had such good records on salmonella that their whole chicken carcasses were tested by federal inspectors about every two years. The results of those tests did not foreshadow any problems. Even subsequent testing after the outbreak started found rates of salmonella on chicken parts in the plants only slightly higher than the typical plant.
While inspectors found some safety violations in the plants, they were not appreciably different from other plants around the country.
"Right now, the evidence we have is that the production process was not out of control," Engeljohn said. "It can be improved, but it was not out of control."
Why didn't the USDA shut down the plants when officials knew about the problems?
On Oct. 7, the agency threatened to shut down the plants by pulling its inspectors but did not actually do so. That's because Foster Farms assured federal inspectors that it was making changes to improve its processes. One change the company has pledged to make is introducing an antimicrobial treatment on chicken parts.
Europe seems to be doing better with salmonella. What are nations there doing that the U.S. isn't?
While the U.S. has made no progress in cutting the incidence of salmonella infections in humans since 1996, the European Union cut its infections by almost half between 2004 and 2009.
Some countries, such as Sweden, have greatly reduced salmonella in chickens sold for food. But they have done so in part by aggressively managing the human pathogen in flocks, killing infected birds by the tens of thousands.
What is the U.S. doing to control salmonella at chicken farms?
In the United States, federal inspectors do not monitor chickens being raised for slaughter for human pathogens such as salmonella Heidelberg. In fact, the USDA's Food Safety and Inspection Service has no jurisdiction over chickens at that stage. It starts looking at the birds when they are brought to the plants to be killed and processed, like the Foster Farms facilities in Central California.
If you eat chicken, how can you protect yourself from salmonella?
To kill the bacteria in raw chicken, it should be cooked to at least 165 degrees, according to Foodsafety.gov.
It sounds counterintuitive, but do not wash your raw chicken. That's a common way that cross-contamination occurs in the home kitchen.
"Anything it touches - your hands, your sink, your counter - treat it like it is contaminated and clean it up afterwards," said Jean Weese, professor of poultry science at Auburn University.
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