The recent listeria outbreak from cantaloupe shows that large-scale occurrences of serious illnesses linked to tainted food have grown more common over the years, partly because much of what we eat takes a long and winding road from farm to fork.
A cantaloupe grown on a Colorado field may make four or five stops before it reaches the dinner table. There's the packing house where it is cleaned and packaged, then the distributor who contracts with retailers to sell the melons in large quantities. A processor may cut or bag the fruit. The retail distribution center is where the melons are sent out to various stores. Finally it's stacked on display at the grocery store.
Imported fruits and vegetables, which make up almost two-thirds of the produce consumed in the United States, have an even longer journey.
"Increasingly with agribusiness you have limited producers of any given food, so a breakdown in a facility or plant or in a large field crop operation exposes thousands because of the way the food is distributed," says Dr. Brian Currie, an infectious disease specialist at Montefiore Medical Center in New York.
The Colorado cantaloupe crop that's linked to 84 illnesses and as many as 17 deaths in 19 states has traveled so far and wide that producer Jensen Farms doesn't even know exactly where their fruit ended up.
The company said last week that it can't provide a list of retailers that sold the tainted fruit because the melons were sold and resold. It named the 28 states where the fruit was shipped, but people in other states have reported getting sick.
A Kansas-based processor that purchased cantaloupes from Jensen, Carol's Cuts, didn't provide a notice to its customers that it had sold the farm's cantaloupes until nine days after the original recall.
"The food chain is very complex," says Sherri McGarry, a senior adviser in the Food and Drug Administration's Office of Foods. "There are many steps, and the more steps there are the harder it can be to link up each step to identify what the common source" of an outbreak is.
Fewer and larger farms and companies dominate food production in the country. That has driven some consumers to seek out farmers markets and locally grown produce. Supermarkets now highlight food grown nearby, while farmers markets have soared in popularity.
But many in the produce industry have come together to try and improve the ability to quickly trace food from field to plate.
This is good business. Large recalls, such as spinach in 2006, peanuts in 2009 and eggs in 2010, tend to depress sales for an entire product industry, even if only one company or grower was responsible for the outbreak.
Recent outbreaks of salmonella in peanuts and eggs, which are ingredients in thousands of foods, have been more widespread and sickened more people than have the tainted cantaloupe.
"There has been a laser focus on improving traceability so any recall can identify the affected product immediately and not have an effect on the rest of the entire category," says Ray Gilmer of United Fresh Produce Association, which represents the country's largest growers.
Gilmer says that larger food companies have no choice but to take food safety very seriously.
"The stakes for a large company to have a food safety incident are huge," he said. "It could destroy their company."
Listeria, a bacteria found in soil and water, often turns up in processed meats because it can contaminate a processing facility and stay there for a long period of time. It's also common in unpasteurized cheeses and unpasteurized milk, though less so produce such as cantaloupe.
The disease can cause fever, muscle aches, gastrointestinal symptoms and even death. One in five people who have listeria can die.
A food safety law passed by Congress last year gives the FDA new power to improve tracing food through the system. Food safety advocates say the law will help make the food network safer by focusing on making every step in the chain safer and making it easier to find the source of outbreaks.
For the first time, larger farms are required to submit plans detailing how they are keeping their produce safe.
Erik Olson, director of food and consumer safety programs for the Pew Health Group, says it is critical that those improvements are made to prevent more, larger outbreaks as the system grows more complex.
"Clearly the food industry has just changed enormously in the last several decades," Olson said. "It would be virtually impossible to sit down and eat a meal and eat food that hasn't come from all over the world."
Centers for Disease Control and Prevention: http://www.cdc.gov/listeria/index.html